LM96000CIMT/NOPB [NSC]

IC 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO24, MO-153AD, TSSOP-24, Power Management Circuit;
LM96000CIMT/NOPB
型号: LM96000CIMT/NOPB
厂家: National Semiconductor    National Semiconductor
描述:

IC 1-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO24, MO-153AD, TSSOP-24, Power Management Circuit

光电二极管
文件: 总32页 (文件大小:367K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
July 23, 2008  
LM96000  
Hardware Monitor with Integrated Fan Control  
Noise filtering of temperature reading for fan control  
General Description  
1.0°C digital temperature sensor resolution  
3 PWM fan speed control outputs  
The LM96000, hardware monitor, has a two wire digital inter-  
face compatible with SMBus 2.0. Using an 8-bit ΣΔ ADC, the  
LM96000 measures:  
Provides high and low PWM frequency ranges  
4 fan tachometer inputs  
– the temperature of two remote diode connected transis-  
tors as well as its own die  
Monitors 5 VID control lines  
24-pin TSSOP package  
– the VCCP, 2.5V, 3.3VSBY, 5.0V, and 12V supplies (in-  
ternal scaling resistors).  
XOR-tree test mode  
To set fan speed, the LM96000 has three PWM outputs that  
are each controlled by one of three temperature zones. High  
and low PWM frequency ranges are supported. The LM96000  
includes a digital filter that can be invoked to smooth temper-  
ature readings for better control of fan speed. The LM96000  
has four tachometer inputs to measure fan speed. Limit and  
status registers for all measured values are included.  
Key Specifications  
Voltage Measurement Accuracy  
±2% FS (max)  
8-bits, 1°C  
Resolution  
Temperature Sensor Accuracy  
±3°C (max)  
Temperature Range  
LM96000 Operational  
Remote Temp Accuracy  
Power Supply Voltage  
Power Supply Current  
0°C to +85°C  
0°C to +125°C  
+3.0V to +3.6V  
0.53 mA  
Features  
2-wire, SMBus 2.0 compliant, serial digital interface  
8-bit ΣΔ ADC  
Monitors VCCP, 2.5V, 3.3 VSBY, 5.0V, and 12V  
motherboard/processor supplies  
Applications  
Monitors 2 remote thermal diodes  
Desktop PC  
Programmable autonomous fan control based on  
temperature readings  
Microprocessor based equipment  
(e.g. Base-stations, Routers, ATMs, Point of Sales)  
Block Diagram  
20084601  
© 2008 National Semiconductor Corporation  
200846  
www.national.com  
Connection Diagram  
24 Pin TSSOP  
20084602  
NS Package MTC24E  
Top View  
LM96000CIMT (61 units per rail), or  
LM96000CIMTX (2500 units per tape and reel)  
Pin Descriptions  
Symbol  
Pin  
Type  
Name and Function/Connection  
SMBDAT  
1
Digital I/O  
(Open-Drain)  
System Management Bus Data. Open-drain output. 5V tolerant,  
SMBus 2.0 compliant.  
SMBus  
SMBCLK  
2
5
Digital Input  
Digital Input  
Digital Input  
Digital Input  
Digital Input  
Digital Input  
POWER  
System Management Bus Clock. Tied to Open-drain output. 5V  
tolerant, SMBus 2.0 compliant.  
VID0  
VID1  
Voltage identification signal from the processor. This value is read in  
the VID0–VID4 Status Register.  
6
Voltage identification signal from the processor. This value is read in  
the VID0–VID4 Status Register.  
Processor  
VID Lines  
VID2  
VID3  
VID4  
3.3V  
7
Voltage identification signal from the processor. This value is read in  
the VID0–VID4 Status Register.  
8
Voltage identification signal from the processor. This value is read in  
the VID0–VID4 Status Register.  
19  
4
Voltage identification signal from the processor. This value is read in  
the VID0–VID4 Status Register.  
+3.3V pin. Can be powered by +3.3V Standby power if monitoring in  
low power states is required. This pin also serves as the analog input  
to monitor the 3.3V supply. This pin should be bypassed with a 0.1µf  
capacitor in parallel with 100pf. A bulk capacitance of approximately  
10µf needs to be in the near vicinity of the LM96000.  
Power  
GND  
5V  
3
GROUND  
Analog Input  
Analog Input  
Analog Input  
Analog Input  
Ground for all analog and digital circuitry.  
Analog input for +5V monitoring.  
20  
21  
22  
23  
12V  
Analog input for +12V monitoring.  
Voltage  
Inputs  
2.5V  
Analog input for +2.5V monitoring.  
VCCP_IN  
Analog input for VCCP (processor voltage) monitoring.  
www.national.com  
2
Symbol  
Pin  
Type  
Name and Function/Connection  
Remote1+  
18  
Remote Thermal Positive input (current source) from the first remote thermal diode.  
Diode Positive  
Input  
Serves as the positive input into the A/D. Connected to THERMDA  
pin of Pentium processor or the base of a diode connected  
MMBT3904 NPN transistor.  
Remote1−  
Remote2+  
Remote2−  
17  
16  
15  
Remote Thermal Negative input (current sink) from the first remote thermal diode.  
Diode Negative Serves as the negative input into the A/D. Connected to THERMDC  
Input  
pin of Pentium processor or the emmiter of a diode connected  
MMBT3904 NPN transistor.  
Remote  
Diodes  
Remote Thermal Positive input (current source) from the first remote thermal diode.  
Diode Positive  
Output  
Serves as the positive input into the A/D. Connected to THERMDA  
pin of Pentium processor or the base of a diode connected  
MMBT3904 NPN transistor.  
Remote Thermal Negative input (current sink) from the first remote thermal diode.  
Diode Negative Serves as the negative input into the A/D. Connected to THERMDC  
Input  
pin of Pentium processor or the emmiter of a diode connected  
MMBT3904 NPN transistor.  
TACH1  
TACH2  
TACH3  
11  
12  
9
Digital Input  
Digital Input  
Digital Input  
Digital Input  
Input for monitoring tachometer output of fan 1.  
Input for monitoring tachometer output of fan 2.  
Input for monitoring tachometer output of fan 3.  
Fan  
Tachometer  
Inputs  
TACH4/Address  
Select  
14  
Input for monitoring tachometer output of fan 4. If in Address Select  
Mode, determines the SMBus address of the LM96000.  
PWM1/xTest Out  
24  
10  
13  
Digital Open-Drain Fan speed control 1. When in XOR tree test mode, functions as XOR  
Output Tree output.  
PWM2  
Digital Open-Drain Fan speed control 2.  
Output  
Fan Control  
PWM3/Address  
Enable  
Digital Open-Drain Fan speed control 3. Pull to ground at power on to enable Address  
Output  
Select Mode (Address Select pin controls SMBus address of the  
device).  
3
www.national.com  
Storage Temperature  
−65°C to +150°C  
Absolute Maximum Ratings (Notes 1, 2)  
If Military/Aerospace specified devices are required,  
please contact the National Semiconductor Sales Office/  
Distributors for availability and specifications.  
Soldering process must comply with National's reflow  
temperature profile specifications. Refer to  
www.national.com/packaging/. (Note 6)  
Supply Voltage, V+  
Voltage on Any Digital Input or  
Output Pin  
−0.5V to 6.0V  
−0.5V to 6.0V  
Operating Ratings (Notes 1, 2)  
LM96000 Operating Temperature  
0°C TA +85°C  
Range  
Voltage on 12V Analog Input  
Voltage on 5V Analog Input  
Voltage on Remote1+, Remote2+,  
Current on Remote1−, Remote2−  
Voltage on Other Analog Inputs  
Input Current on Any Pin (Note 3)  
Package Input Current (Note 3)  
Package Dissipation at TA = 25°C  
ESD Susceptibility (Note 4)  
Human Body Model  
−0.5V to 16V  
−0.5V to 6.66V  
−0.5V to (V+ + 0.05V)  
±1 mA  
Remote Diode Temperature Range  
0°C TD +125°C  
Supply Voltage (3.3V nominal)  
VIN Voltage Range  
+12V VIN  
+3.0V to +3.6V  
−0.05V to 16V  
−0.05V to 6.66V  
3.0V to 4.4V  
−0.5V to 6.0V  
±5 mA  
±20 mA  
See (Note 5)  
+5V VIN  
+3.3V VIN  
VCCP_IN and All Other Inputs  
VID0–VID4  
Typical Supply Current  
−0.05V to (V+ + 0.05V)  
−0.05V to 5.5V  
0.53 mA  
2500V  
250V  
Machine Model  
DC Electrical Characteristics  
The following specifications apply for V+ = 3.0V to 3.6V, and all analog input source impedance RS = 50Ω unless otherwise specified  
in conditions. Boldface limits apply for TA = TJ over TMIN =0°C to TMAX=85°C; all other limits TA =TJ= 25°C. TA is the ambient  
temperature of the LM96000; TJ is the junction temperature of the LM96000; TD is the thermal diode junction temperature.  
Symbol  
Parameter  
Conditions  
Typical  
Limits  
Units  
(Limits)  
(Note 7)  
(Note 8)  
POWER SUPPLY CHARACTERISTICS  
Supply Current (Note 9)  
Converting, Interface and  
Fans Inactive, Peak Current  
1.8  
3.5  
mA (max)  
mA  
Converting, Interface and  
Fans Inactive, Average  
Current  
0.53  
Power-On Reset Threshold Voltage  
1.6  
2.8  
V (min)  
V (max)  
TEMPERATURE TO DIGITAL CONVERTER CHARACTERISTICS  
Resolution  
1
8
°C  
Bits  
Temperature Accuracy (See (Note 10) for Thermal TD=25°C  
Diode Processor Type)  
±2.5  
±3  
°C (max)  
°C (max)  
°C (max)  
°C (max)  
TD=0°C to 100°C  
±1  
±1  
TD=100°C to 125°C  
±4  
Temperature Accuracy using Internal Diode (Note  
11)  
±3  
IDS  
External Diode Current Source  
High Level  
Low Level  
188  
11.75  
16  
280  
µA (max)  
µA  
External Diode Current Ratio  
ANALOG TO DIGITAL CONVERTER CHARACTERISTICS  
TUE  
DNL  
Total Unadjusted Error(Note 12)  
Differential Non-linearity  
±2  
%FS (max)  
LSB  
1
Power Supply Sensitivity  
±1  
%/V  
Total Monitoring Cycle Time (Note 13)  
All Voltage and Temperature  
readings  
182  
200  
ms (max)  
Input Resistance, all analog inputs  
210  
140  
400  
kΩ (min)  
kΩ (max)  
www.national.com  
4
Symbol  
Parameter  
Conditions  
Typical  
Limits  
Units  
(Limits)  
(Note 7)  
(Note 8)  
DIGITAL OUTPUT: PWM1, PWM2, PWM3, XTESTOUT  
IOL  
Logic Low Sink Current  
Logic Low Level  
VOL=0.4V  
8
mA (min)  
V (max)  
VOL  
IOUT = +8 mA  
0.4  
SMBUS OPEN-DRAIN OUTPUT: SMBDAT  
VOL  
IOH  
Logic Low Output Voltage  
High Level Output Current  
IOUT = +4 mA  
VOUT = V+  
0.4V  
10  
V (max)  
0.1  
µA (max)  
SMBUS INPUTS: SMBCLK. SMBDAT  
VIH  
Logic Input High Voltage  
Logic Input Low Voltage  
Logic Input Hysteresis Voltage  
2.1  
0.8  
V (min)  
V (max)  
mV  
VIL  
VHYST  
300  
DIGITAL INPUTS: ALL  
VIH  
VIL  
VTH  
IIH  
Logic Input High Voltage  
2.1  
0.8  
V (min)  
V (max)  
V
Logic Input Low Voltage  
Logic Input Threshold Voltage  
Logic High Input Current  
Logic Low Input Current  
Digital Input Capacitance  
1.5  
0.005  
−0.005  
20  
VIN = V+  
10  
µA (max)  
µA (max)  
pF  
IIL  
VIN = GND  
−10  
CIN  
AC Electrical Characteristics  
The following specifications apply for V+ = 3.0V to 3.6V unless otherwise specified in conditions. Boldface limits apply for TA  
TJ over TMIN =0°C to TMAX=85°C; all other limits TA =TJ= 25°C.  
=
Symbol  
Parameter  
Conditions  
Typical  
Limits  
Units  
(Limits)  
(Note 7)  
(Note 8)  
TACHOMETER ACCURACY  
Fan Count Accuracy  
±10  
% (max)  
(max)  
Fan Full-Scale Count  
65536  
Fan Counter Clock Frequency  
Fan Count Conversion Time  
90  
kHz  
0.7  
1.4  
sec (max)  
FAN PWM OUTPUT  
Frequency Setting Accuracy  
Frequency Range  
±10  
% (max)  
10  
30  
Hz  
kHz  
Duty-Cycle Range  
Low frequency range  
0 to 100  
% (max)  
%
Duty-Cycle Resolution (8-bits)  
Spin-Up Time Interval Range  
0.390625  
100  
4000  
ms  
ms  
Spin-Up Time Interval Accuracy  
±10  
±10  
% (max)  
SPIKE SMOOTHING FILTER  
Time Interval Deviation  
Time Interval Range  
% (max)  
35  
0.8  
sec  
sec  
SMBUS TIMING CHARACTERISTICS  
fSMB  
SMBus Operating Frequency  
10  
100  
kHz (min)  
kHz (max)  
fBUF  
SMBus Free Time Between Stop And  
Start Condition  
4.7  
4.0  
µs (min)  
tHD_STA  
Hold Time After (Repeated) Start  
Condition (after this period, the first clock  
is generated)  
µs (min)  
5
www.national.com  
Symbol  
Parameter  
Conditions  
Typical  
Limits  
Units  
(Limits)  
(Note 7)  
(Note 8)  
tSU:STA  
tSU:STO  
tHD:DAT  
Repeated Start Condition Setup Time  
Stop Condition Setup Time  
Data Output Hold Time  
4.7  
4.0  
µs (min)  
µs (min)  
ns (min)  
ns (max)  
ns (min)  
300  
930  
250  
tSU:DAT  
Data Input Setup Time  
tTIMEOUT  
Data And Clock Low Time To Reset Of  
SMBus Interface Logic(Note 14)  
25  
35  
ms (min)  
ms (max)  
tLOW  
tHIGH  
Clock Low Period  
Clock High Period  
4.7  
µs (min)  
4.0  
50  
µs (min)  
µs (max)  
tF  
Clock/Data Fall Time  
Clock/Data Rise Time  
300  
1000  
500  
ns (max)  
ns (max)  
ms (max)  
tR  
tPOR  
Time from Power-On-Reset to LM96000 V+ > 2.8V  
Reset and Operational  
20084603  
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is  
functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed  
specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test  
conditions.  
Note 2: All voltages are measured with respect to GND, unless otherwise noted.  
Note 3: When the input voltage (VIN) at any pin exceeds the power supplies (VIN < GND or VIN >V+ ), the current at that pin should be limited to 5mA. The 20mA  
maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 5mA to four. Parasitic  
components and/or ESD protection circuitry are shown below for the LM96000's pins. The nominal breakdown voltage the zener is 6.5V. Care should be taken  
not to forward bias the parasitic diode D1 present on pins D+ and D−. Doing so by more that 50 mV may corrupt temperature measurements. SNP stands for  
snap-back device.  
www.national.com  
6
 
 
Pin #  
Pin Name  
SMBDAT  
SMBCLK  
GND  
Circuit  
All Input Circuits  
1
2
3
4
A
B
3.3V  
5
6
7
8
9
VID0  
VID1  
A
VID2  
VID3  
TACH3  
10  
11  
12  
13  
14  
PWM2  
TACH1  
TACH2  
PWM3/AddEnable  
TACH4/AddSel  
15  
16  
17  
18  
19  
REMOTE2−  
REMOTE2+  
REMOTE1−  
REMOTE1+  
VID4  
C
D
C
D
A
20  
21  
22  
23  
24  
5V  
12V  
E
A
2.5V  
VCCP_IN  
PWM1/xTEXTOUT  
Note 4: Human body model, 100pF discharged through a 1.5kΩ resistor. Machine model, 200pF discharged directly into each pin.  
Note 5: Thermal resistance junction-to-ambient when attached to a double-sided printed circuit board with 1 oz. foil is 113 °C/W.  
Note 6: Reflow temperature profiles are different for packages containing lead (Pb) than for those that do not.  
Note 7: Typicals are at TA = 25°C and represent most likely parametric norm.  
Note 8: Limits are guaranteed to National's AOQL (Average Outgoing Quality Level).  
Note 9: The average current can be calculated from the peak current using the following equation:  
Quiescent current will not increase substantially with an SMBus transaction.  
Note 10: The accuracy of the LM96000CIMT is guaranteed when using the thermal diode of Intel Pentium 4 90nm processors or any thermal diode with a non-  
ideality of 1.011 and series resistance of 3.33. When using a 2N3904 type transistor as a thermal diode the error band will be typically shifted by -?°C.  
Note 11: Local temperature accuracy does not include the effects of self-heating. The rise in temperature due to self-heating is the product of the internal power  
dissipation of the LM96000 and the thermal resistance. See (Note 5) for the thermal resistance to be used in the self-heating calculation.  
Note 12: TUE , total unadjusted error, includes ADC gain, offset, linearity and reference errors. TUE is defined as the "actual Vin" to achieve a given code transition  
minus the "theoretical Vin" for the same code. Therefore, a positive error indicates that the input voltage is greater than the theoretical input voltage for a given  
code. If the theoretical input voltage was applied to an LM96000 that has positive error, the LM96000's reading would be less than the theoretical.  
Note 13: This specification is provided only to indicate how often temperature and voltage data is updated. The LM96000 can be read at any time without regard  
to conversion state (and will yield last conversion result).  
Note 14: Holding the SMBDAT and/or SMBCLK lines Low for a time interval greater than tTIMEOUT will reset the LM96000's SMBus state machine, therefore setting  
the SMBDAT pin to a high impedance state.  
7
www.national.com  
 
 
 
 
 
 
 
 
 
 
 
During the first SMBus communication TACH4 and PWM3  
can be used to change the SMBus address of the LM96000  
to 0101101b or 0101100b. LM96000 address selection pro-  
cedure:  
Functional Description  
1.0 SMBUS  
The LM96000 is compatible with devices that are compliant  
to the SMBus 2.0 specification. More information on this bus  
can be found at: http://www.smbus.org/. Compatibility of SM-  
Bus2.0 to other buses is discussed in the SMBus 2.0 speci-  
fication.  
A 10 kpull-down resistor to ground on the PWM3/  
Address Enable pin is required. Upon power up, the  
LM96000 will be placed into Address Enable mode and  
assign itself an SMBus address according to the state of  
the Address Select input. The LM96000 will latch the  
address during the first valid SMBus transaction in which  
the first five bits of the targeted address match those of the  
LM96000 address, 0 1011b. This feature eliminates the  
possibility of a glitch on the SMBus interfering with address  
selection. When the PWM3/Address Enable pin is not  
used to change the SMBus address of the LM96000, it will  
remain in a high state until the first communication with the  
LM96000. After the first SMBus transaction is completed  
PWM3 and TACH4 will return to normal operation.  
1.1 Addressing  
LM96000 is designed to be used primarily in desktop systems  
that require only one monitoring device.  
If only one LM96000 is used on the motherboard, the designer  
should be sure that the PWM3/Address Enable pin is High  
during the first SMBus communication addressing the  
LM96000. PWM3/Address Enable is an open drain I/O pin  
that at power-on defaults to the input state of Address En-  
able. A maximum of 10k pull-up resistance on PWM3/Ad-  
dress Enable is required to assure that the SMBus address  
of the device will be locked at 010 1110b, which is the default  
address of the LM96000.  
Address Enable  
Address Select  
Board Implementation  
SMBus Address  
0
0
1
0
1
X
010 1100b, 2Ch  
010 1101b, 2Dh  
010 1110b, 2Eh  
Pulled to ground through a 10 kresistor  
Pulled to 3.3V or to GND through a 10 kresistor  
Pulled to 3.3V through a 10 kresistor  
In this way, up to three LM96000 devices can exists on an  
SMBus at any time. Multiple LM96000 devices can be used  
to monitor additional processors and temperature zones.  
When using the non-default addresses the TACH4 and  
PWM3 will not function. As shown in the timing diagram the  
Address Enable pin must remain low in order for the latched  
address to remain in effect. If the address enable pin is pulled  
high after the first SMBus communication, then the LM96000  
SMBus address will revert to the default value (2Eh) after the  
first five clocks of next SMBus communication.  
20084604  
Address Latch Enable low during and after first communication  
20084610  
Address Latch Enable high during first communication  
www.national.com  
8
2.0 FAN REGISTER DEVICE SET-UP  
– [6A-6Ch] Set the temperature absolute limits.  
– [64-66h] Set the PWM minimum duty cycle.  
– [6D-6Eh] Set the temperature Hysteresis values.  
The BIOS will follow the following steps to configure the fan  
registers on the LM96000. The registers corresponding to  
each function are listed. All steps may not be necessary if  
default values are acceptable. Regardless of all changes  
made by the BIOS to the fan limit and parameter registers  
during configuration, the LM96000 will continue to operate  
based on default values until the START bit (bit 0), in the  
Ready/Lock/Start/Override register (address 40h), is set.  
Once the fan mode is updated, by setting the START bit to 1,  
the LM96000 will operate using the values that were set by  
the BIOS in the fan control limit and parameter registers  
(adress 5Ch through 6Eh).  
2. [40h] Set bit 0 (START) to update fan control and limit  
register values and start fan control based on these new  
values.  
3. [40h] Set bit 1 (LOCK) to lock the fan limit and parameter  
registers (optional).  
3.0 AUTO FAN CONTROL OPERATING MODE  
The LM96000 includes the circuitry for automatic fan control.  
In Auto Fan Mode, the LM96000 will automatically adjust the  
PWM duty cycle of the PWM outputs. PWM outputs are as-  
signed to a thermal zone based on the fan configuration  
registers. It is possible to have more than one PWM output  
assigned to a thermal zone. For example, PWM outputs 2 and  
3, connected to two chassis fans, may both be controlled by  
thermal zone 2. At any time, the temperature of a zone ex-  
ceeds its absolute limit, all PWM outputs will go to 100% duty  
cycle to provide maximum cooling to the system.  
1. Set limits and parameters (not necessarily in this order):  
– [5F-61h] Set PWM frequencies and auto fan  
control range.  
– [62-63h] Set spike smoothing and min/off.  
– [5C-5Eh] Set the fan spin-up delays.  
– [5C-5Eh] Match each fan with a corresponding  
thermal zone.  
– [67-69h] Set the fan temperature limits.  
9
www.national.com  
4.0 REGISTER SET  
Register Read/ Register  
Address Write Name  
Bit 7 Bit 6 Bit 5 Bit 4  
(MSB)  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
(LSB)  
Default Lock?  
Value  
20h  
21h  
22h  
23h  
24h  
25h  
R
R
R
R
R
R
2.5V  
7
7
7
7
7
7
6
6
6
6
6
6
5
5
5
5
5
5
4
4
4
4
4
4
3
3
3
3
3
3
2
2
2
2
2
2
1
1
1
1
1
1
0
0
0
0
0
0
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
VCCP_IN  
3.3V  
5V  
12V  
Processor (Zone1)  
Temp  
26h  
27h  
28h  
29h  
2Ah  
2Bh  
2Ch  
2Dh  
2Eh  
2Fh  
30h  
R
R
R
R
R
R
R
R
R
R
Internal (Zone2) Temp  
Remote (Zone3) Temp  
Tach1 LSB  
7
7
6
6
5
5
4
4
3
3
2
2
1
0
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
N/A  
1
0
7
6
5
4
3
2
LEVEL1  
LEVEL0  
Tach1 MSB  
15  
7
14  
6
13  
5
12  
4
11  
3
10  
2
9
8
Tach2 LSB  
LEVEL1  
LEVEL0  
Tach2 MSB  
15  
7
14  
6
13  
5
12  
4
11  
3
10  
2
9
8
Tach3 LSB  
LEVEL1  
LEVEL0  
Tach3 MSB  
15  
7
14  
6
13  
5
12  
4
11  
3
10  
2
9
8
Tach4 LSB  
LEVEL1  
LEVEL0  
Tach4 MSB  
15  
7
14  
6
13  
5
12  
4
11  
3
10  
2
9
1
8
0
R/W Fan1 Current PWM  
Duty  
31h  
32h  
R/W Fan2 Current PWM  
Duty  
7
7
7
6
6
6
5
5
5
4
4
4
3
3
3
2
2
1
1
0
0
N/A  
N/A  
R/W Fan3 Current PWM  
Duty  
3Eh  
3Fh  
40h  
R
R
Company ID  
2
1
0
01h  
68h  
00h  
Version/Stepping  
VER3 VER2 VER1 VER0 STP3  
STP2  
STP1  
LOCK  
STP0  
START  
R/W Ready/Lock/Start/  
Override  
RES RES RES RES OVRID READY  
41h  
42h  
R
R
R
Interrupt Status  
Register 1  
ERR ZN3  
ZN2  
ZN1  
5V  
3.3V  
VCCP  
RES  
2.5V  
12V  
00h  
00h  
Interrupt Status  
Register 2  
ERR2 ERR1 FAN4 FAN3 FAN2  
FAN1  
43h  
44h  
45h  
46h  
47h  
48h  
49h  
4Ah  
4Bh  
4Ch  
4Dh  
4Eh  
VID0–4  
RES RES RES VID4 VID3  
VID2  
VID1  
VID0  
N/A  
00h  
FFh  
00h  
FFh  
00h  
FFh  
00h  
FFh  
00h  
FFh  
81h  
R/W 2.5V Low Limit  
R/W 2.5V High Limit  
R/W VCCP Low Limit  
R/W VCCP High Limit  
R/W 3.3V Low Limit  
R/W 3.3V High Limit  
R/W 5V Low Limit  
R/W 5V High Limit  
R/W 12V Low Limit  
R/W 12V High Limit  
7
7
7
7
7
7
7
7
7
7
7
6
6
6
6
6
6
6
6
6
6
6
5
5
5
5
5
5
5
5
5
5
5
4
4
4
4
4
4
4
4
4
4
4
3
3
3
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
R/W Processor (Zone1)  
Low Temp  
4Fh  
50h  
R/W Processor (Zone1)  
High Temp  
7
7
6
6
5
5
4
4
3
3
2
2
1
1
0
0
7Fh  
81h  
R/W Internal (Zone2) Low  
Temp  
www.national.com  
10  
Register Read/ Register  
Address Write Name  
Bit 7 Bit 6 Bit 5 Bit 4  
(MSB)  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
(LSB)  
Default Lock?  
Value  
51h  
52h  
53h  
R/W Internal (Zone2) High  
7
7
7
6
6
6
5
5
5
4
4
4
3
3
3
2
2
2
1
1
1
0
0
0
7Fh  
81h  
7Fh  
Temp  
R/W Remote (Zone3) Low  
Temp  
R/W Remote (Zone3) High  
Temp  
54h  
55h  
56h  
57h  
58h  
59h  
5Ah  
5Bh  
5Ch  
R/W Tach1 Minimum LSB  
R/W Tach1 Minimum MSB  
R/W Tach2 Minimum LSB  
R/W Tach2 Minimum MSB  
R/W Tach3 Minimum LSB  
R/W Tach3 Minimum MSB  
R/W Tach4 Minimum LSB  
R/W Tach4 Minimum MSB  
R/W Fan1 Configuration  
7
15  
7
6
14  
6
5
13  
5
4
12  
4
3
11  
3
2
10  
2
1
0
FFh  
FFh  
FFh  
FFh  
FFh  
FFh  
FFh  
FFh  
9
8
1
0
15  
7
14  
6
13  
5
12  
4
11  
3
10  
2
9
8
1
0
15  
7
14  
6
13  
5
12  
4
11  
3
10  
2
9
8
1
9
0
8
15  
14  
13  
12  
11  
RES  
10  
SPIN2  
ZON2 ZON1 ZON0 INV  
ZON2 ZON1 ZON0 INV  
ZON2 ZON1 ZON0 INV  
SPIN1  
SPIN0  
62h  
5Dh  
5Eh  
5Fh  
R/W Fan2 Configuration  
R/W Fan3 Configuration  
RES  
RES  
SPIN2  
SPIN2  
FRQ2  
SPIN1  
SPIN1  
FRQ1  
SPIN0  
SPIN0  
FRQ0  
62h  
62h  
R/W Fan1 Range/  
Frequency  
RAN3 RAN2 RAN1 RAN0 HLFRQ  
RAN3 RAN2 RAN1 RAN0 HLFRQ  
RAN3 RAN2 RAN1 RAN0 HLFRQ  
C4h  
60h  
61h  
62h  
63h  
R/W Fan2 Range/  
Frequency  
FRQ2  
FRQ2  
ZN1-2  
ZN3-2  
FRQ1  
FRQ1  
ZN1-1  
ZN3-1  
FRQ0  
FRQ0  
ZN1-0  
ZN3-0  
C4h  
R/W Fan3 Range/  
Frequency  
C4h  
R/W Min/Off, Zone1 Spike OFF3 OFF2 OFF1 RES ZN1E  
Smoothing  
00H  
R/W Zone2, Zone3 Spike  
Smoothing  
ZN2E ZN2-2 ZN2-1 ZN2-0 ZN3E  
00h  
64h  
65h  
66h  
67h  
68h  
69h  
6Ah  
R/W Fan1 PWM Minimum  
R/W Fan2 PWM Minimum  
R/W Fan3 PWM Minimum  
R/W Zone1 Fan Temp Limit  
R/W Zone2 Fan Temp Limit  
R/W Zone3 Fan Temp Limit  
7
7
7
7
7
7
7
6
6
6
6
6
6
6
5
5
5
5
5
5
5
4
4
4
4
4
4
4
3
3
3
3
3
3
3
2
2
2
2
2
2
2
1
1
1
1
1
1
1
0
0
0
0
0
0
0
80h  
80h  
80h  
5Ah  
5Ah  
5Ah  
R/W Zone1 Temp Absolute  
Limit  
64h  
6Bh  
6Ch  
6Dh  
R/W Zone2 Temp Absolute  
Limit  
7
7
6
6
5
5
4
4
3
3
2
2
1
1
0
0
64h  
R/W Zone3 Temp Absolute  
Limit  
64h  
R/W Zone1, Zone2  
Hysteresis  
H1-3 H1-2 H1-1 H1-0  
H2-3  
H2-2  
H2-1  
H2-0  
44h  
6Eh  
6Fh  
R/W Zone3 Hysteresis  
H3-3 H3-2 H3-1 H3-0  
RES  
RES  
RES  
RES  
T2-0  
RES  
RES  
T1-1  
RES  
XEN  
T1-0  
40h  
R/W XOR Test Tree Enable RES RES RES RES  
00h  
74h  
75h  
R/W Tach Monitor Mode  
R/W Fan Spin-up Mode  
RES RES T3/4-1 T3/4-0 T2-1  
RES RES RES RES  
00h  
RES PWM3 SU PWM2 SU PWM1 SU  
7h  
Note: Reserved bits will always return 0 when read.  
11  
www.national.com  
4.1 Register 20-24h: Voltage Reading  
Register  
Address  
Read/  
Write  
Register  
Name  
Bit 7  
(MSB)  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
(LSB)  
Default  
Value  
20h  
21h  
22h  
23h  
24h  
R
R
R
R
R
2.5V  
VCCP  
3.3V  
5V  
7
7
7
7
7
6
6
6
6
6
5
5
5
5
5
4
4
4
4
4
3
3
3
3
3
2
2
2
2
2
1
1
1
1
1
0
0
0
0
0
N/A  
N/A  
N/A  
N/A  
N/A  
12V  
The Register Names difine the typical input voltage at which the reading is ¾ full scale or C0h.  
The Voltage Reading registers are updated automatically by the LM96000 at a minimum frequency of 4 Hz. These registers are  
read only — a write to these registers has no effect.  
4.2 Register 25-27h: Temperature Reading  
Register  
Address  
Read/ Register  
Bit 7  
(MSB)  
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0  
Default  
Write  
Name  
(LSB) Value  
25h  
26h  
27h  
R
R
R
Processor (Zone1) Temp  
Internal (Zone2) Temp  
Remote (Zone3) Temp  
7
7
7
6
6
6
5
5
5
4
4
4
3
3
3
2
2
2
1
1
1
0
0
0
N/A  
N/A  
N/A  
The Temperature Reading registers reflect the current temperatures of the internal and remote diodes. Processor (Zone1) Temp  
register reports the temperature measured by the thermal diode connected to the Remote1− and Remote1+ pins, Remote (Zone3)  
Temp register reports the temperature measured by the thermal diode connected to the the Remote2− and Remote2+ pins, and  
the Internal (Zone2) Temp register reports the temperature measured by the internal (junction) temperature sensor. Temperatures  
are represented as 8 bit, 2’s complement, signed numbers, in Celsius, as shown below in Table 1. The Temperature Reading  
register will return a value of 80h if the remote diode pins are not used by the board designer or are not functioning properly. This  
reading will cause the zone limit bit(s) (bits 6 and 4) in the Interrupt Status Register (41h) and the remote diode fault status bit(s)  
(bit 6 or 7) in the Interrupt Status Register 2 (42h) to be set. The Temperature Reading registers are updated automatically by the  
LM96000 at a minimum frequency of 4 Hz. These registers are read only — a write to these registers has no effect.  
TABLE 1. Temperature vs Register Reading  
Temperature  
Reading (Dec)  
Reading (Hex)  
−127°C  
−127  
81h  
.
.
.
.
.
.
.
.
.
−50°C  
−50  
CEh  
.
.
.
.
.
.
.
.
.
0°C  
0
00h  
.
.
.
.
.
.
.
.
.
127°C  
127  
7Fh  
80h  
(SENSOR ERROR)  
www.national.com  
12  
 
4.3 Register 28-2Fh: Fan Tachometer Reading  
Register  
Address  
Read/  
Write  
Register  
Name  
Bit 7  
(MSB)  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
(LSB)  
Default  
Value  
28h  
29h  
R
R
Tach1 LSB  
Tach1 MSB  
7
15  
6
14  
5
13  
4
12  
3
11  
2
10  
LEVEL1  
9
LEVEL0  
8
N/A  
N/A  
2Ah  
2Bh  
R
R
Tach2 LSB  
Tach2 MSB  
7
15  
6
14  
5
13  
4
12  
3
11  
2
10  
LEVEL1  
9
LEVEL0  
8
N/A  
N/A  
2Ch  
2Dh  
R
R
Tach3 LSB  
Tach3 MSB  
7
15  
6
14  
5
13  
4
12  
3
11  
2
10  
LEVEL1  
9
LEVEL0  
8
N/A  
N/A  
2Eh  
2Fh  
R
R
Tach4 LSB  
Tach4 MSB  
7
15  
6
14  
5
13  
4
12  
3
11  
2
10  
LEVEL1  
9
LEVEL0  
8
N/A  
N/A  
The Fan Tachometer Reading registers contain the number of 11.111 µs periods (90 kHz) between full fan revolutions. The results  
are based on the time interval of two tachometer pulses, since most fans produce two tachometer pulses per full revolution. These  
registers will be updated at least once every second.  
The value, for each fan, is represented by a 16-bit unsigned number.  
The Fan Tachometer Reading registers will always return an accurate fan tachometer measurement, even when a fan is disabled  
or non-functional.  
The least two significant bits (LEVEL1 and LEVEL2) of the least significant byte are used to indicate the accuracy level of the  
tachometer reading. The accuracy ranges from most to least accurate. [LEVEL1:LEVEL2]=11indicates a most accurate value,  
[LEVEL1:LEVEL2]=01 indicates the least accurate value and [LEVEL1:LEVEL2]=00 is reserved for future use.  
FF FFh indicates that the fan is not spinning, or that the tachometer input is not connected to a valid signal. These registers are  
read only — a write to these registers has no effect.  
When the LSByte of the LM96000 16-bit register is read, the other byte (MSByte) is latched at the current value until it is read. At  
the end of the MSByte read the Fan Tachometer Reading registers are updated.  
During spin-up, the PWM duty cycle reported is 0%.  
13  
www.national.com  
4.4 Register 30-32h: Current PWM Duty  
Register  
Address  
Read/ Register  
Bit 7  
(MSB)  
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0  
Default  
Write  
R/W  
R/W  
R/W  
Name  
(LSB) Value  
30h  
31h  
32h  
Fan1 Current PWM Duty  
Fan2 Current PWM Duty  
Fan3 Current PWM Duty  
7
7
7
6
6
6
5
5
5
4
4
4
3
3
3
2
2
2
1
1
1
0
0
0
N/A  
N/A  
N/A  
The Current PWM Duty registers store the current duty cycle at each PWM output. At initial power-on, the PWM duty cycle is 100%  
and thus, when read, this register will return FFh. After the Ready/Lock/Start/Override register Start bit is set, this register and the  
PWM signals will be updated based on the algorithm described in the Auto Fan Control Operating Mode section.  
When read, the Current PWM Duty registers return the current PWM duty cycle. These registers are read only unless the fan is in  
manual (test) mode, in which case a write to these registers will directly control the PWM duty cycle for each fan. The PWM duty  
cycle is represented as shown in the following table.  
Current Duty  
0%  
Value (Decimal)  
Value (Hex)  
00h  
0
1
0.3922%  
01h  
.
.
.
.
.
.
.
.
.
25.098%  
64  
40h  
.
.
.
.
.
.
.
.
.
50.196%  
128  
80h  
.
.
.
.
.
.
.
.
.
100%  
255  
FFh  
4.5 Register 3Eh: Company ID  
Register  
Address  
Read/  
Write  
Register  
Name  
Bit 7  
(MSB)  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
(LSB)  
Default  
Value  
3Eh  
R
Company ID  
7
6
5
4
3
2
1
0
01h  
The company ID register contains the company identification number. For National Semiconductor this is 01h. This number is  
assigned by Intel and is a method for uniquely identifying the part manufacturer. This register is read only — a write to this register  
has no effect.  
4.6 Register 3Fh: Version/Stepping  
Register  
Address  
Read/  
Write  
Register  
Name  
Bit 7  
(MSB)  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
(LSB)  
Default  
Value  
3Fh  
R
Version/Stepping  
VER3  
VER2  
VER1  
VER0  
STP3  
STP2  
STP1  
STP0  
68h  
The four least significant bits of the Version/Stepping register [3.0] contain the current stepping of the LM96000 silicon. The four  
most significant bits [7.4] reflect the LM96000 base device number when set to a value of 0110b. For the LM96000, this register  
will read 01101000b (68h). Bit 3 of the stepping field is set to indicate that the LM96000 is a super-set of the LM85 family of products.  
The register is used by application software to identify which device in the hardware monitor family of ASICs has been implemented  
in the given system. Based on this information, software can determine which registers to read from and write to. Further, application  
software may use the current stepping to implement work-arounds for bugs found in a specific silicon stepping.  
This register is read only — a write to this register has no effect.  
www.national.com  
14  
4.7 Register 40h: Ready/Lock/Start/Override  
Register Read/ Register  
Address Write Name  
Bit 7  
(MSB)  
Bit 6 Bit 5 Bit 4 Bit 3  
Bit 2  
Bit 1  
Bit 0  
(LSB)  
Default  
Value  
40h  
R/W  
Ready/Lock/Start/Override  
RES  
RES RES RES OVRID READY LOCK START 00h  
Bit  
Name  
R/W  
Default  
Description  
0
START  
R/W  
0
When software writes a 1 to this bit, the LM96000 fan monitoring and PWM output  
control functions will use the values set in the fan control limit and parameter registers  
(address 5Ch through 6Eh). Before this bit is set, the LM96000 will not update the used  
register values, the default values will remain in effect. Whenever this bit is set to 0, the  
LM96000 fan monitoring and PWM output control functions use the default fan limits  
and parameters, regardless of the current values in the limit and parameter registers  
(5C through 6Eh). The LM96000 will preserve the values currently stored in the limit and  
parameter registers when this bit is set or cleared. This bit is not effected by the state  
of the Lock bit.  
It is expected that all limit and parameter registers will be set by BIOS or application  
software prior to setting this bit.  
1
LOCK  
R/W  
0
0
Setting this bit to 1 locks specified limit and parameter registers. Once this bit is set, limit  
and parameter registers become read only and will remain locked until the device is  
powered off. This register bit becomes read only once it is set.  
2
3
READY  
OVRID  
R
The LM96000 sets this bit automatically after the part is fully powered up, has completed  
the power-up-reset process, and after all A/D converters are properly functioning.  
R/W  
If this bit is set to 1, all PWM outputs will go to 100% duty cycle regardless of whether  
or not the lock bit is set. The OVRID bit has precedence over the disabled mode.  
Therefore, when OVRID is set the PWM will go to 100% even if the PWM is in the  
disabled mode.  
4–7  
Reserved  
R
0
Reserved  
15  
www.national.com  
4.8 Register 41h: Interrupt Status Register 1  
Register  
Address  
Read/  
Write  
Register  
Name  
Bit 7  
(MSB)  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
(LSB)  
Default  
Value  
41h  
R
Interrupt Status 1  
ERR  
ZN3  
ZN2  
ZN1  
5V  
3.3V  
VCCP  
2.5V  
00h  
The Interrupt Status Register 1 bits will be automatically set, by the LM96000, whenever a fault condition is detected. A fault  
condition is detected whenever a measured value is outside the window set by its limit registers. ZN3 and ZN1 bits will be set when  
a diode fault condition, such as a disconect or short, is detected. More than one fault may be indicated in the interrupt register  
when read. This register will hold a set bit(s) until the event is read by software. The contents of this register will be cleared (set to  
0) automatically by the LM96000 after it is read by software, if the fault condition is no longer exists. Once set, the Interrupt Status  
Register 1 bits will remain set until a read event occurs, even if the fault condition no longer exists  
This register is read only — a write to this register has no effect.  
Bit  
Name  
R/W  
Default  
Description  
0
2.5V_Error  
R
0
The LM96000 automatically sets this bit to 1 when the 2.5V input voltage is less  
than or equal to the limit set in the 2.5V Low Limit register or greater than the limit  
set in the 2.5V High Limit register.  
1
2
3
4
VCCP_Error  
3.3V_Error  
5V_Error  
R
R
R
R
0
0
0
0
The LM96000 automatically sets this bit to 1 when the VCCP input voltage is less  
than or equal to the limit set in the VCCP Low Limit register or greater than the limit  
set in the VCCP High Limit register.  
The LM96000 automatically sets this bit to 1 when the 3.3V input voltage is less  
than or equal to the limit set in the 3.3V Low Limit register or greater than the limit  
set in the 3.3V High Limit register.  
The LM96000 automatically sets this bit to 1 when the 5V input voltage is less than  
or equal to the limit set in the 5V Low Limit register or greater than the limit set in  
the 5V High Limit register.  
Zone 1 Limit  
Exceeded  
The LM96000 automatically sets this bit to 1 when the temperature input measured  
by the Remote1− and Remote1+ inputs is less than or equal to the limit set in the  
Processor (Zone1) Low Temp register or more than the limit set in the Processor  
(Zone1) High Temp register. This bit will be set when a diode fault is detected.  
5
6
7
Zone 2 Limit  
Exceeded  
R
R
R
0
0
0
The LM96000 automatically sets this bit to 1 when the temperature input measured  
by the internal temperature sensor is less than or equal to the limit set in the Internal  
(Zone2) Low Temp register or greater than the limit set in the Internal (Zone2) High  
Temp register.  
Zone 3 Limit  
Exceeded  
The LM96000 automatically sets this bit to 1 when the temperature input measured  
by the Remote2− and Remote2+ inputs is less than or equal to the limit set in the  
Internal (Zone2) Low Temp register or greater than the limit set in the Remote  
(Zone3) High Temp register. This bit will be set when a diode fault is detected.  
Error in Status  
Register 2  
If there is a set bit in Status Register 2, this bit will be set to 1.  
www.national.com  
16  
4.9 Register 42h: Interrupt Status Register 2  
Register Read/ Register  
Address Write Name  
Bit 7  
(MSB)  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1 Bit 0  
(LSB) Value  
ERR2 ERR1 FAN4 FAN3 FAN2 FAN1 RES 12V 00h  
Default  
42h  
R
Interrupt Status Register 2  
The Interrupt Status Register 2 bits will be automatically set, by the LM96000, whenever a fault condition is detected. Interrupt  
Status Register 2 identifies faults caused by temperature sensor error, fan speed droping below minimum set by the tachometer  
minimum register, the 12V input voltage going outside the window set by its limit registers. Interrupt Status Register 2 will hold a  
set bit until the event is read by software. The contents of this register will be cleared (set to 0) automatically by the LM96000 after  
it is ready by software, if fault condition no longer exists. Once set, the Interrupt Status Register 2 bits will remain set until a read  
event occurs, even if the fault no longer exists  
This register is read only — a write to this register has no effect.  
Bit  
Name  
R/W  
Default  
Description  
0
+12V_Error  
R
0
The LM96000 automatically sets this bit to 1 when the 12V input voltage either falls  
below the limit set in the 12V Low Limit register or exceeds the limit set in the 12V  
High Limit register.  
1
2
Reserved  
R
R
0
0
Reserved  
Fan1 Stalled  
The LM96000 automatically sets this bit to 1 when the TACH1 input reading is above  
the value set in the Tach1 Minimum MSB and LSB registers.  
3
4
5
6
Fan2 Stalled  
Fan3 Stalled  
Fan4 Stalled  
R
R
R
R
0
0
0
0
The LM96000 automatically sets this bit to 1 when the TACH2 input reading is above  
the value set in the Tach2 Minimum MSB and LSB registers.  
The LM96000 automatically sets this bit to 1 when the TACH3 input reading is above  
the value set in the Tach3 Minimum MSB and LSB registers.  
The LM96000 automatically sets this bit to 1 when the TACH4 input reading is above  
the value set in the Tach4 Minimum MSB and LSB registers.  
Remote Diode 1  
Fault  
The LM96000 automatically sets this bit to 1 when there is either a short or open  
circuit fault on the Remote1+ or Remote1− thermal diode input pins. A diode fault  
will also set bit 4, Diode 1 Zone Limit bit, of Interrupt Status Register 1.  
7
Remote Diode 2  
Fault  
R
0
The LM96000 automatically sets this bit to 1 when there is either a short or open  
circuit fault on the Remote2+ or Remote2− thermal diode input pins. A diode fault  
will also set bit 6, Diode 2 Zone Limit bit, of Interrupt Status Register 1.  
4.10 Register 43h: VID  
Register  
Address  
Read/  
Write  
Register  
Name  
Bit 7  
(MSB)  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
(LSB)  
Default  
Value  
43h  
R
VID0–4  
RES  
RES  
RES  
VID4  
VID3  
VID2  
VID1  
VID0  
The VID register contains the values of LM96000 VID0–VID4 input pins. This register indicates the status of the VID lines that  
interconnect the processor to the Voltage Regulator Module (VRM). Software uses the information in this register to determine the  
voltage that the processor is designed to operate at. With this information, software can then dynamically determine the correct  
values to place in the VCCP Low Limit and VCCP High Limit registers.  
This register is read only — a write to this register has no effect.  
17  
www.national.com  
4.11 Registers 44-4Dh: Voltage Limit Registers  
Register  
Address  
Read/  
Write  
Register  
Name  
Bit 7  
(MSB)  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
(LSB)  
Default  
Value  
44h  
45h  
46h  
47h  
48h  
49h  
4Ah  
4Bh  
4Ch  
4Dh  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
2.5V Low Limit  
2.5V High Limit  
VCCP Low Limit  
VCCP High Limit  
3.3V Low Limit  
3.3V High Limit  
5V Low Limit  
7
7
7
7
7
7
7
7
7
7
6
6
6
6
6
6
6
6
6
6
5
5
5
5
5
5
5
5
5
5
4
4
4
4
4
4
4
4
4
4
3
3
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
00h  
FFh  
00h  
FFh  
00h  
FFh  
00h  
FFh  
00h  
FFh  
5V High Limit  
12V Low Limit  
12V High Limit  
If a voltage input either exceeds the value set in the voltage high limit register or falls below the value set in the voltage low limit  
register, the corresponding bit will be set automatically by the LM96000 in the interrupt status registers (41-42h). Voltages are  
presented in the registers at ¾ full scale for the nominal voltage, meaning that at nominal voltage, each input will be C0h, as shown  
in Table 2.  
Setting the Ready/Lock/Start/Override register Lock bit has no effect on these registers.  
TABLE 2. Voltage Limits vs Register Setting  
Input  
Nominal  
Voltage  
Register Setting at  
Nominal Voltage  
Maximum  
Voltage  
Register Reading at  
Maximum Voltage  
Minimum  
Voltage  
Register Reading at  
Minimum Voltage  
2.5V  
2.5V  
C0h  
C0h  
C0h  
C0h  
C0h  
3.32V  
3.00V  
4.38V  
6.64V  
16.00V  
FFh  
FFh  
FFh  
FFh  
FFh  
0V  
00h  
00h  
AFh  
00h  
00h  
VCCP 2.25V  
0V  
3.3V  
5V  
3.3V  
5.0V  
12.0V  
3.0V  
0V  
12V  
0V  
www.national.com  
18  
 
4.12 Registers 4E-53h: Temperature Limit Registers  
Register  
Address  
Read/  
Write  
Register  
Name  
Bit 7  
(MSB)  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
(LSB)  
Default  
Value  
4Eh  
4Fh  
50h  
51h  
52h  
53h  
R/W  
R/W  
R/W  
R/W  
R/W  
R/W  
Processor (Zone1)  
Low Temp  
7
7
7
7
7
7
6
6
6
6
6
6
5
5
5
5
5
5
4
4
4
4
4
4
3
3
3
3
3
3
2
2
2
2
2
2
1
1
1
1
1
1
0
0
0
0
0
0
81h  
7Fh  
81h  
7Fh  
81h  
7Fh  
Processor (Zone1)  
High Temp  
Processor (Zone2)  
Low Temp  
Processor (Zone2)  
High Temp  
Processor (Zone3)  
Low Temp  
Processor (Zone3)  
High Temp  
If an external temperature input or the internal temperature sensor either exceeds the value set in the corresponding high limit  
register or falls below the value set in the corresponding low limit register, the corresponding bit will be set automatically by the  
LM96000 in the Interrupt Status Register 1 (41h). For example, if the temperature read from the Remote1− and Remote1+ inputs  
exceeds the Processor (Zone1) High Temp register limit setting, Interrupt Status Register 1 ZN1 bit will be set. The temperature  
limits in these registers are represented as 8 bit, 2’s complement, signed numbers in Celsius, as shown below in Table 3.  
Setting the Ready/Lock/Start/Override register Lock bit has no effect on these registers.  
TABLE 3. Temperature Limits vs Register Settings  
Temperature  
Reading (Decimal)  
Reading (Hex)  
−127°C  
−127  
81h  
.
.
.
.
.
.
.
.
.
−50°C  
−50  
CEh  
.
.
.
.
.
.
.
.
.
0°C  
0
00h  
.
.
.
.
.
.
.
.
.
50°C  
50  
32h  
.
.
.
.
.
.
.
.
.
127°C  
127  
7Fh  
19  
www.national.com  
 
4.13 Registers 54-5Bh: Fan Tachometer Low Limit  
Register  
Address  
Read/  
Write  
Register  
Name  
Bit 7  
(MSB)  
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0  
(LSB)  
Default  
Value  
54h  
55h  
R/W  
R/W  
Tach1 Minimum LSB  
Tach1 Minimum MSB  
7
15  
6
14  
5
13  
4
12  
3
11  
2
10  
1
9
0
8
FFh  
FFh  
56h  
57h  
R/W  
R/W  
Tach2 Minimum LSB  
Tach2 Minimum MSB  
7
15  
6
14  
5
13  
4
12  
3
11  
2
10  
1
9
0
8
FFh  
FFh  
58h  
59h  
R/W  
R/W  
Tach3 Minimum LSB  
Tach3 Minimum MSB  
7
15  
6
14  
5
13  
4
12  
3
11  
2
10  
1
9
0
8
FFh  
FFh  
5Ah  
5Bh  
R/W  
R/W  
Tach4 Minimum LSB  
Tach4 Minimum MSB  
7
15  
6
14  
5
13  
4
12  
3
11  
2
10  
1
9
0
8
FFh  
FFh  
The Fan Tachometer Low Limit registers indicate the tachometer reading under which the corresponding bit will be set in the  
Interrupt Status Register 2 register. In Auto Fan Control mode, the fan can run at low speeds, so care should be taken in software  
to ensure that the limit is high enough not to cause sporadic alerts. The fan tachometer will not cause a bit to be set in Interrupt  
Status Register 2 if the current value in Current PWM Duty registers is 00h or if the fan 1 disabled via the Fan Configuration Register.  
Interrupts will never be generated for a fan if its minimum is set to FF FFh.  
Given the insignificance of Bit 0 and Bit 1, these bits could be programmed to remember which fan is which, as follows.  
Fan  
Bit 1  
Bit 0  
CPU  
0
0
1
1
0
1
0
1
Memory  
Chassis Front  
Chassis Rear  
Setting the Ready/Lock/Start/Override register Lock bit has no effect these registers.  
www.national.com  
20  
4.14 Registers 5C-5Eh: Fan Configuration  
Register Read/ Register  
Address Write Name  
Bit 7  
(MSB)  
Bit 6  
Bit 5  
Bit 4 Bit 3 Bit 2  
Bit 1  
Bit 0  
(LSB) Value  
Default Lock?  
5Ch  
5Dh  
5Eh  
R/W  
R/W  
R/W  
Fan1 Configuration  
Fan2 Configuration  
Fan3 Configuration  
ZON2 ZON1 ZON0 INV  
ZON2 ZON1 ZON0 INV  
ZON2 ZON1 ZON0 INV  
RES SPIN2 SPIN1 SPIN0 62h  
RES SPIN2 SPIN1 SPIN0 62h  
RES SPIN2 SPIN1 SPIN0 62h  
This register becomes Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further attempts to write to this  
register shall have no effect. After power up the default value is used whenever the Ready/Lock/Start/Override register Start bit is  
cleared even though modifications to this register are possible.  
Bits [7:5] Zone/Mode  
Bits [7:5] of the Fan Configuration registers associate each fan with a temperature sensor. When in Auto Fan Mode the fan will be  
assigned to a zone, and its PWM duty cycle will be adjusted according to the temperature of that zone. If ‘Hottest’ option is selected  
(101 or 110), the fan will be controlled by the hottest of zones 2 and 3, or of zones 1, 2, and 3. To determine the ‘Hottest’ zone the  
PWM level for each zone is calculated then the the highest PWM value is selected. When in manual control mode, the Current  
PWM duty registers (30h-32h) become Read/Write. It is then possible to control the PWM outputs with software by writing to these  
registers. When the fan is disabled (100) the corresponding PWM output should be driven low (or high, if inverted).  
Zone 1: External Diode 1 (processor)  
Zone 2: Internal Sensor  
Zone 3: External Diode 2  
TABLE 4. Fan Zone Setting  
ZON[2:0]  
000  
Fan Configuration  
Fan on zone 1 auto  
001  
Fan on zone 2 auto  
010  
Fan on zone 3 auto  
011  
Fan always on full  
100  
Fan disabled  
101  
Fan controlled by hottest of zones 2, 3  
Fan controlled by hottest of zones 1, 2, 3  
Fan manually controlled (Test Mode)  
110  
111  
Bit [4] PWM Invert  
Bit [4] inverts the PWM output. If set to 0, 100% duty cycle will yield an output that is always high. If set to 1, 100% duty cycle will  
yield an output that is always low.  
Bit [3] Reserved  
Bits [2:0] Spin Up  
Bits [2:0] specify the ‘spin up’ time for the fan. When a fan is being started from a stationary state, the PWM output is held at 100%  
duty cycle for the time specified in the table below before scaling to a lower speed.  
TABLE 5. Fan Spin-Up Register  
SPIN[2:0]  
000  
Spin Up Time  
0 sec  
001  
100 ms  
010  
250 ms  
011  
400 ms  
100  
700 ms  
101  
1000 ms  
2000 ms  
4000 ms  
110  
111  
21  
www.national.com  
4.15 Registers 5F-61h: Auto Fan Speed Range, PWM Frequency  
Register Read/ Register  
Address Write Name  
Bit 7  
(MSB)  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
(LSB) Value  
Default Lock?  
5Fh  
60h  
61h  
R/W  
R/W  
R/W  
Zone1 Range/Fan1  
Frequency  
RAN3 RAN2 RAN1 RAN0 HLFRQ FRQ2 FRQ1 FRQ0 C4h  
RAN3 RAN2 RAN1 RAN0 HLFRQ FRQ2 FRQ1 FRQ0 C4h  
RAN3 RAN2 RAN1 RAN0 HLFRQ FRQ2 FRQ1 FRQ0 C4h  
Zone2 Range/Fan2  
Frequency  
Zone3 Range/Fan3  
Frequency  
In Auto Fan Mode, when the temperature for a zone is above the Temperature Limit (Registers 67-69h) and below its Absolute  
Temperature Limit (Registers 6A-6Ch), the speed of a fan assigned to that zone is determined as follows.  
When the temperature reaches the Fan Temp Limit for a zone, the PWM output assigned to that zone will be Fan PWM Minimum.  
Between Fan Temp Limit and (Fan Temp Limit + Range), the PWM duty cycle will increase linearly according to the temperature  
as shown in the figure below. The PWM duty cycle will be 100% at (Fan Temp Limit + Range).  
20084606  
FIGURE 1. Fan Activity above Fan Temp Limit  
Example for PWM1 assigned to Zone 1:  
– Zone 1 Fan Temp Limit (Register 67h) is set to 50°C (32h).  
– Range (Register 5Fh) is set to 8°C (6xh).  
– Fan 1 PWM Minimum (Register 64h) is set to 50% (32h).  
In this case, the PWM1 duty cycle will be 50% at 50°C.  
Since (Zone 1 Fan Temp Limit) + (Zone 1 Range) = 50°C + 8°C = 58°C, the fan will run at 100% duty cycle when the temperature  
of the Zone 1 sensor reaches 58°C.  
Since the midpoint of the fan control range is 54°C, and the median duty cycle is 75% (Halfway between the PWM Minimum and  
100%), PWM1 duty cycle would be 75% at 54°C.  
Above (Zone 1 Fan Temp Limit) + (Zone 1 Range), the duty cycle will be 100%.  
PWM frequency bits [3:0]  
The PWM frequency bits [3:0] determine the PWM frequency for the fan.The LM96000 has high and low frequency ranges for the  
PWM outputs, that are controlled by the HLFRQ bit.  
PWM Frequency Selection (Default = 0011 = 30.04 Hz).  
www.national.com  
22  
TABLE 6. Register Setting vs PWM Frequency  
HLFRQ  
Freq [2:0]  
000  
PWM Frequency  
10.01 Hz  
15.02 Hz  
23.14 Hz  
30.04 Hz  
38.16 Hz  
47.06 Hz  
61.38 Hz  
94.12 Hz  
22.5 kHz  
24 kHz  
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
001  
010  
011  
100  
101  
110  
111  
000  
001  
010  
25.7 kHz  
25.7 kHz  
27.7 kHz  
27.7 kHz  
30 kHz  
011  
100  
101  
110  
111  
30 kHz  
Range Selection RAN [3:0]  
RAN [3:0]  
Range (°C)  
0000  
0001  
0010  
0011  
0100  
0101  
0110  
0111  
1000  
1001  
1010  
1011  
1100  
1101  
1110  
1111  
2
2.5  
3.33  
4
5
6.67  
8
10  
13.33  
16  
20  
26.67  
32  
40  
53.33  
80  
This register becomes Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further attempts to write to this  
register shall have no effect. After power up the default value is used whenever the Ready/Lock/Start/Override register Start bit is  
cleared even though modifications to this register are possible.  
4.16 Registers 62, 63h: Min/Off, Spike Smoothing  
Register Read/ Register  
Address Write Name  
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Default Lock?  
(MSB) (LSB) Value  
62h  
63h  
R/W Min/Off, Zone1 Spike Smoothing OFF3 OFF2 OFF1 RES ZN1E ZN1-2 ZN1-1 ZN1-0 00h  
R/W Zone2, Zone3 Spike Smoothing ZN2E ZN2-2 ZN2-1 ZN2-0 ZN3E ZN3-2 ZN3-1 ZN3-0 00h  
The Off/Min Bits [7:5] specify whether the duty cycle will be 0% or Minimum Fan Duty when the measured temperature falls below  
the Temperature LIMIT register setting (see table below). OFF1 applies to fan 1, OFF2 applies to fan 2, and OFF3 applies to fan  
3.  
23  
www.national.com  
If the Remote1 or Remote2 pins are connected to a processor or chipset, instantaneous temperature spikes may be sampled by  
the LM96000. If these spikes are not ignored, the CPU fan (if connected to LM96000) may turn on prematurely and produce  
unpleasant noise. For this reason, any zone that is connected to a chipset or processor should have spike smoothing enabled.  
When spike smoothing is enabled, the temperature reading registers will still reflect the current value of the temperature — not the  
‘smoothed out’ value.  
ZN1E, ZN2E, and ZN3E enable temperature smoothing for zones 1, 2, and 3 respectively.  
ZN1-2, ZN1-1, and ZN1-0 control smoothing time for Zone 1.  
ZN2-2, ZN2-1, and ZN2-0 control smoothing time for Zone 2.  
ZN3-2, ZN3-1, and ZN3-0 control smoothing time for Zone 3.  
These registers become ready only when the Ready/Lock/Start/Override register Lock bit is set. Any further attempts to write to  
these registers shall have no effect.  
20084607  
FIGURE 2. What LM96000 Auto Fan Control Sees With and Without Spike Smoothing  
TABLE 7. Spike Smoothing  
ZN-X[2:0]  
000  
Spike Smoothed Over  
35 seconds  
001  
17.6 seconds  
11.8 seconds  
7.0 seconds  
010  
011  
100  
4.4 seconds  
101  
3.0 seconds  
110  
1.6 seconds  
111  
.8 seconds  
TABLE 8. PWM Output Below Limit Depending on Value of Off/Min  
Off/Min  
PWM Action  
0
1
At 0% duty below LIMIT  
At Min PWM Duty below LIMIT  
www.national.com  
24  
4.17 Registers 64-66h: Minimum PWM Duty Cycle  
Register  
Address  
Read/ Register  
Bit 7  
(MSB)  
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0  
Default Lock?  
Write  
Name  
(LSB) Value  
64h  
65h  
66h  
R/W  
Fan1 PWM Minimum  
7
7
7
6
6
6
5
5
5
4
4
4
3
3
3
2
2
2
1
1
1
0
0
0
80h  
80h  
80h  
R/W  
R/W  
Fan2 PWM Minimum  
Fan3 PWM Minimum  
These registers specify the minimum duty cycle that the PWM will output when the measured temperature reaches the Temperature  
LIMIT register setting.  
This register becomes Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further attempts to write to this  
register shall have no effect. After power up the default value is used whenever the Ready/Lock/Start/Override register Start bit is  
cleared even though modifications to this register are possible.  
TABLE 9. PWM Duty vs Register Setting for PWM Low Frequency Range  
Current Duty  
0%  
Value (Decimal)  
Value (Hex)  
00h  
0
1
0.3922%  
01h  
.
.
.
.
.
.
.
.
.
25.098%  
64  
40h  
.
.
.
.
.
.
.
.
.
50.196%  
128  
80h  
.
.
.
.
.
.
.
.
.
100%  
255  
FF  
PWM Duty Cycle vs Register Setting for PWM High Frequency Range  
22.5KHz PWM Frequency  
24KHz PWM Frequency  
PWM Duty Cycle Value in Decimal  
Level (%)  
Value in Hex  
PWM Duty Cycle Value in Decimal  
Level (%)  
Value in Hex  
0.00  
6.25  
0
0
0
0
0
1 - 15  
01 - 0F  
10 - 1F  
20 - 2F  
30 - 3F  
40 - 4F  
50 - 5F  
60 - 6F  
70 - 7F  
80 - 8F  
90 - 9F  
A0 - AF  
B0 - BF  
C0 - CF  
D0 - DF  
E0 - EF  
F0 - FF  
6.67  
1 - 16  
01 - 10  
11 - 21  
22 - 32  
33 - 43  
44 - 54  
55 - 65  
66 - 76  
77 - 88  
89 - 99  
9A - AA  
AB - BB  
BC - CC  
CD - DD  
DE - EE  
EF - FF  
12.50  
18.75  
25.00  
31.25  
37.50  
43.75  
50.00  
56.25  
62.50  
68.75  
75.00  
81.25  
87.50  
93.75  
100.00  
16 - 31  
13.33  
20.00  
26.67  
33.33  
40.00  
46.67  
53.33  
60.00  
66.67  
73.33  
80.00  
86.67  
93.33  
100.00  
17 - 33  
32 - 47  
34 - 50  
48 - 63  
51 - 67  
64 - 79  
68 - 84  
80 - 95  
85 - 101  
102 - 118  
119 - 136  
137 - 153  
154 - 170  
171 - 187  
188 - 204  
205 - 221  
222 - 238  
239 - 255  
96 - 111  
112 - 127  
128 - 143  
144 - 159  
160 - 175  
176 - 191  
192 - 207  
208 - 223  
224 - 239  
240 - 255  
25  
www.national.com  
25.7KHz PWM Frequency  
27.7KHz PWM Frequency  
PWM Duty Cycle Value in Decimal  
Level (%)  
Value in Hex  
PWM Duty Cycle Value in Decimal  
Level (%)  
Value in Hex  
0
0
0
0
0
0
7.14  
1 - 17  
01 - 11  
12 - 24  
25 - 36  
37 - 48  
49 - 5A  
5B - 6D  
6E - 7F  
80 - 91  
92 - A4  
A5 - B6  
B7 - C8  
C9 - DA  
DB - ED  
EE - FF  
7.69  
1 - 19  
01 - 13  
14 - 26  
27 - 3A  
3B - 4E  
4F - 61  
62 - 75  
76 - 89  
8A - 9D  
9E - B0  
B1 - C4  
C5 - D8  
D9 - EB  
EC - FF  
14.29  
21.43  
28.57  
35.71  
42.86  
50.00  
57.14  
64.29  
71.43  
78.57  
85.71  
92.86  
100.00  
18 - 36  
15.38  
23.08  
30.77  
38.46  
46.15  
53.85  
61.54  
69.23  
76.92  
84.62  
92.31  
100.00  
20 - 38  
37 - 54  
39 - 58  
55 - 72  
59 - 78  
73 - 90  
79 - 97  
91 - 109  
110 - 127  
128 - 145  
146 - 164  
165 - 182  
183 - 200  
201 - 218  
219 - 237  
238 - 255  
98 - 117  
118 - 137  
138 - 157  
158 - 176  
177 - 196  
197 - 216  
217 - 235  
236 - 255  
30KHz PWM Frequency  
PWM Duty Cycle Value in Decimal  
Level (%)  
Value in Hex  
0
0
0
8.33  
1 - 20  
01 - 14  
15 - 2A  
2B - 3F  
40 - 54  
55 - 6A  
6B - 7F  
80 - 94  
95 - AA  
AB - BF  
C0 - D4  
D5 - EA  
EB - FF  
16.67  
25.00  
33.33  
41.67  
50.00  
58.33  
66.67  
75.00  
83.33  
91.67  
100.00  
21 - 42  
43 - 63  
64 - 84  
85 - 106  
107 - 127  
128 - 148  
149 - 170  
171 - 191  
192 - 212  
213 - 234  
235 - 255  
4.18 Registers 67-69h: Temperature Limit  
Register  
Address  
Read/ Register  
Write Name  
Bit 7  
(MSB)  
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0  
Default Lock?  
(LSB) Value  
67h  
68h  
69h  
R/W  
R/W  
R/W  
Zone1 Fan Temp Limit  
7
7
7
6
6
6
5
5
5
4
4
4
3
3
3
2
2
2
1
1
1
0
0
0
5Ah  
5Ah  
5Ah  
Zone2 Fan Temp Limit  
Zone3 Fan Temp Limit  
These are the temperature limits for the individual zones. When the current temperature equals this limit, the fan will be turned on  
if it is not already. When the temperature exceeds this limit, the fan speed will be increased according to the algorithm set forth in  
the Auto Fan Range, PWM Frequency register description. Default = 90°C = 5Ah  
This register becomes Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further attempts to write to this  
register shall have no effect. After power up the default value is used whenever the Ready/Lock/Start/Override register Start bit is  
cleared even though modifications to this register are possible.  
www.national.com  
26  
TABLE 10. Temperature Limit vs Register Setting  
Temperature Reading (Decimal)  
Reading (Hex)  
−127°C  
−127  
81h  
.
.
.
.
.
.
.
.
.
−50°C  
−50  
CEh  
.
.
.
.
.
.
.
.
.
0°C  
0
00h  
.
.
.
.
.
.
.
.
.
50°C  
50  
32h  
.
.
.
.
.
.
.
.
.
127°C  
127  
7Fh  
4.19 Registers 6A-6Ch: Absolute Temperature Limit  
Register Read/  
Address Write  
Register  
Name  
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Default Lock?  
(MSB)  
(LSB) Value  
6Ah  
6Bh  
6Ch  
R/W  
R/W  
R/W  
Zone1 Absolute Temp Limit  
Zone2 Absolute Temp Limit  
Zone3 Absolute Temp Limit  
7
6
6
6
5
5
5
4
4
4
3
3
3
2
2
2
1
1
1
0
0
0
64h  
64h  
64h  
7
7
In the Auto Fan mode, if a zone exceeds the temperature set in the Absolute Temperature Limit register, all of the PWM outputs  
will incresase its duty cycle to 100%. This is a safety feature that attempts to cool the system if there is a potentially catastrophic  
thermal event. If set to 80h (-128°C), the feature is disabled. Default=100°C=64h  
These registers become Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further attempts to write to  
these registers shall have no effect. After power up the default values are used whenever the Ready/Lock/Start/Override register  
Start bit is cleared even though modifications to these registers are possible.  
TABLE 11. Absolute Limit vs Register Setting  
Temperature Reading (Decimal)  
Reading (Hex)  
−127°C  
−127  
81h  
.
.
.
.
.
.
.
.
.
−50°C  
−50  
CEh  
.
.
.
.
.
.
.
.
.
0°C  
0
00h  
.
.
.
.
.
.
.
.
.
50°C  
50  
32h  
.
.
.
.
.
.
.
.
.
127°C  
127  
7Fh  
27  
www.national.com  
4.20 Registers 6D-6Eh: Zone Hysteresis Registers  
Register Read/ Register  
Address Write Name  
Bit 7  
(MSB)  
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0  
Default Lock?  
(LSB) Value  
6Dh  
6Eh  
R/W  
R/W  
Zone1 and Zone2 Hysteresis  
Zone3 Hysteresis  
H1-3  
H1-2 H1-1 H1-0 H2-3 H2-2 H2-1 H2-0  
H3-2 H3-1 H3-0 RES RES RES RES  
44h  
H3-3  
40h  
If the temperature is above Fan Temp Limit, then drops below Fan Temp Limit, the following will occur:  
– The fan will remain on, at Fan PWM Minimum, until the temperature goes a certain amount below Fan Temp Limit.  
– The Hysteresis registers control this amount. See below table for details.  
These registers become Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further attempts to write to  
thses registers shall have no effect. After power up the default value is used whenever the Ready/Lock/Start/Override register Start  
bit is cleared even though modifications to this register are possible.  
TABLE 12. Hysteresis Settings  
Setting  
HYSTERESIS  
0h  
0°C  
.
.
.
.
.
.
5h  
5°C  
.
.
.
.
.
.
Fh  
15°C  
4.21 Register 6Fh: Test Register  
Register  
Address  
Read/  
Write  
Register  
Name  
Bit 7  
(MSB)  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
RES  
Bit 2  
Bit 1  
Bit 0  
(LSB)  
Default  
Value  
6Fh  
R/W  
Test Register  
RES  
RES  
RES  
RES  
RES  
RES  
XEN  
00h  
If the XEN bit is set high, the part will be placed into XOR tree test mode. Clearing the bit (writing a 0 to the XEN bit) brings the  
part out of XOR tree test mode.  
This register becomes Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further attempts to write to this  
registers shall have no effect. After power up the default value is used whenever the Ready/Lock/Start/Override register Start bit  
is cleared even though modifications to this register are possible.  
4.22 Registers 70-7Fh: Vendor Specific Registers  
These registers are for vendor specific features, including test registers. They will not default to a specific value on power up.  
4.22.1 Register 74h: Tachometer Monitor Mode  
Register Read/  
Register  
Name  
Bit 7  
(MSb)  
Bit 6  
Bit 5  
Bit 4  
Bit 3 Bit 2 Bit 1 Bit 0  
(LSb)  
Default Lock?  
Value  
Address  
Write  
74h  
R/W  
Tach Monitor Mode  
RES  
RES T3/4-1 T3/4-0 T2-1 T2-0 T1-1 T1-0  
00h  
Each fan TACH input has 4 possible modes of operation when using the low frequency range for the PWM outputs. Mode 0 is the  
only mode that is available when using the high frequecy range for the PWM outputs. The modes for TACH3 and TACH4 share  
control bits T3/4-[1:0]; TACH2 is controlled by T2-[1:0]; TACH1 is controlled by T1-[1:0]. The result reported in all modes is based  
on 2 pulses per revolution. In order for modes 2 and 3 to function properly it is required that the:  
PWM1 output must control the fan that has it's tachometer output connected to the TACH1 LM96000 input.  
PWM2 output must control the fan that has it's tachometer output connected to the TACH2 LM96000 input.  
PWM3 output must control the fans that have their tachometer outputs connected to the TACH3 or TACH4 LM96000 inputs.  
www.national.com  
28  
Setting (Tn[1:0]) Mode Function  
00  
01  
10  
11  
0
1
2
3
Traditional tach input monitor, false readings when under minimum detctable RPM  
Traditional tach input monitor, FFFFh reading when under minimum detectable RPM  
Most accurate readings, FFFFh reading when under minimum detectable RPM  
Least effect on programmed PWM of Fan, FFFFh reading when under minimum detectable RPM  
Mode 0: This mode uses the conventional method for fan tachometer pulse detection and does not include any circuitry to  
compensate for PWM Fan drive. This mode should be used when PWM drive is not used to power the fan. This  
mode may report a false RPM reading when under minimum detectable RPM as shown in the following table.  
Mode 1: This mode uses the conventional method for fan tach detection. The reading will be FFFFh if it is below minimum  
detectable RPM.  
Mode 2: This mode is optimized for accurate RPM readings and activates circuitry that extends the lower side of the RPM  
reading as shown in the following table.  
Mode 3: This mode minimizes the effect on the RPM setting and activates circuitry that extends the lower side of the RPM  
reading as shown in the following table.  
PWM Frequency  
10.01  
Mode 0 and 1 Minimum RPM  
Mode 2 and 3 Minimum RPM  
841  
210  
315  
420  
420  
420  
420  
420  
420  
15.02  
1262  
1944  
2523  
3205  
3953  
5156  
7906  
23.14  
30.04  
38.16  
47.06  
61.38  
94.12  
This register is not effected when the Ready/Lock/Start/Override register Lock bit is set. After power up the default value is used  
whenever the Ready/Lock/Start/Override register Start bit is cleared even though modifications to this register are possible.  
4.22.2 Register 75h: Fan Spin-up Mode  
Register Read/  
Address Write  
Register  
Name  
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3  
(MSB)  
Bit 2  
Bit 1  
Bit 0  
(LSB)  
Default Lock?  
Value  
75h  
R/W Fan Spin-up Mode  
RES RES RES RES RES PWM3 SU PWM2 SU PWM1 SU  
7h  
The PWM SU bit configures the PWM spin-up mode. If PWM SU is cleared the spin-up time will terminate after time programmed  
by the Fan Configuration register has elapsed. When set to a 1, the spin-up time will terminate early if the TACH reading exceeds  
the Tach Minimum value or after the time programmed by the Fan Configuration register has elapsed, whichever occurs first.  
This register becomes Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further attempts to write to this  
register shall have no effect. After power up the default value is used whenever the Ready/Lock/Start/Override register Start bit is  
cleared even though modifications to this register are possible.  
4.23 Undefined Registers  
Any reads to undefined registers will always return 00h. Writes to undefined registers will have no effect and will not return an error.  
29  
www.national.com  
5.0 XOR TEST MODE  
Since the test mode an XOR tree, the order of the signals in  
the tree is not important. SMBDAT and SMBCLK are not to  
be included in the test tree.  
The LM96000 incorporates a XOR tree test mode. When the  
test mode is enabled by setting the “XEN” bit high in the Test  
Register at address 6Fh via the SMBus, the part will enter  
XOR test mode.  
20084608  
Applications Information  
20084609  
Typical Applications Schematic  
www.national.com  
30  
Physical Dimensions inches (millimeters) unless otherwise noted  
24-Lead Molded TSSOP Package,  
Order Number LM96000CIMT or LM96000CIMTX  
NS Package Number MTC24E  
JEDEC Registration MO-153, Variation AD  
31  
www.national.com  
Notes  
For more National Semiconductor product information and proven design tools, visit the following Web sites at:  
Products  
www.national.com/amplifiers  
Design Support  
Amplifiers  
WEBENCH  
www.national.com/webench  
www.national.com/AU  
Audio  
www.national.com/audio  
www.national.com/timing  
www.national.com/adc  
Analog University  
App Notes  
Clock Conditioners  
Data Converters  
Displays  
www.national.com/appnotes  
www.national.com/contacts  
www.national.com/quality/green  
www.national.com/packaging  
Distributors  
www.national.com/displays  
www.national.com/ethernet  
www.national.com/interface  
www.national.com/lvds  
Green Compliance  
Packaging  
Ethernet  
Interface  
Quality and Reliability www.national.com/quality  
LVDS  
Reference Designs  
Feedback  
www.national.com/refdesigns  
www.national.com/feedback  
Power Management  
Switching Regulators  
LDOs  
www.national.com/power  
www.national.com/switchers  
www.national.com/ldo  
LED Lighting  
PowerWise  
www.national.com/led  
www.national.com/powerwise  
Serial Digital Interface (SDI) www.national.com/sdi  
Temperature Sensors  
Wireless (PLL/VCO)  
www.national.com/tempsensors  
www.national.com/wireless  
THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION  
(“NATIONAL”) PRODUCTS. NATIONAL MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY  
OR COMPLETENESS OF THE CONTENTS OF THIS PUBLICATION AND RESERVES THE RIGHT TO MAKE CHANGES TO  
SPECIFICATIONS AND PRODUCT DESCRIPTIONS AT ANY TIME WITHOUT NOTICE. NO LICENSE, WHETHER EXPRESS,  
IMPLIED, ARISING BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS  
DOCUMENT.  
TESTING AND OTHER QUALITY CONTROLS ARE USED TO THE EXTENT NATIONAL DEEMS NECESSARY TO SUPPORT  
NATIONAL’S PRODUCT WARRANTY. EXCEPT WHERE MANDATED BY GOVERNMENT REQUIREMENTS, TESTING OF ALL  
PARAMETERS OF EACH PRODUCT IS NOT NECESSARILY PERFORMED. NATIONAL ASSUMES NO LIABILITY FOR  
APPLICATIONS ASSISTANCE OR BUYER PRODUCT DESIGN. BUYERS ARE RESPONSIBLE FOR THEIR PRODUCTS AND  
APPLICATIONS USING NATIONAL COMPONENTS. PRIOR TO USING OR DISTRIBUTING ANY PRODUCTS THAT INCLUDE  
NATIONAL COMPONENTS, BUYERS SHOULD PROVIDE ADEQUATE DESIGN, TESTING AND OPERATING SAFEGUARDS.  
EXCEPT AS PROVIDED IN NATIONAL’S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, NATIONAL ASSUMES NO  
LIABILITY WHATSOEVER, AND NATIONAL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO THE SALE  
AND/OR USE OF NATIONAL PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR  
PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY  
RIGHT.  
LIFE SUPPORT POLICY  
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR  
SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL  
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:  
Life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and  
whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected  
to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform  
can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness.  
National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other  
brand or product names may be trademarks or registered trademarks of their respective holders.  
Copyright© 2008 National Semiconductor Corporation  
For the most current product information visit us at www.national.com  
National Semiconductor  
Americas Technical  
Support Center  
Email: support@nsc.com  
Tel: 1-800-272-9959  
National Semiconductor Europe  
Technical Support Center  
Email: europe.support@nsc.com  
German Tel: +49 (0) 180 5010 771  
English Tel: +44 (0) 870 850 4288  
National Semiconductor Asia  
Pacific Technical Support Center  
Email: ap.support@nsc.com  
National Semiconductor Japan  
Technical Support Center  
Email: jpn.feedback@nsc.com  
www.national.com  

相关型号:

LM96000CIMTX

Hardware Monitor with Integrated Fan Control
NSC

LM96000CIMTX/NOPB

硬件监控器,带风扇控制功能和 6 个电源电压监控器 | PW | 24 | 0 to 125
TI

LM96011

Hardware Monitor with Thermal Diode Input and SensorPath⑩ Bus
NSC

LM96063

LM96063 Remote Diode Digital Temperature Sensor with Integrated Fan Control
TI

LM96063C

LM96063 Remote Diode Digital Temperature Sensor with Integrated Fan Control
TI

LM96063CISD/NOPB

具有 1 条远程和本地通道的风扇控制器,具有风扇降噪功能 | DSC | 10 | -40 to 85
TI

LM96063CISDX

Switch/Digital Output Temperature Sensor, DIGITAL TEMP SENSOR-SERIAL, 11BIT(s), 3Cel, SQUARE, SURFACE MOUNT, MO-299WEED-5, LLP-10
TI

LM96063CISDX/NOPB

具有 1 条远程和本地通道的风扇控制器,具有风扇降噪功能 | DSC | 10 | -40 to 85
TI

LM96080

System Hardware Monitor with 2-Wire Serial Interface
NSC

LM96080

1 条本地通道温度传感器,带风扇转速控制功能和电源电压监控器
TI

LM96080CIMT

LM96080 System Hardware Monitor with 2-Wire Serial Interface
TI

LM96080CIMT

IC 1-CHANNEL POWER SUPPLY MANAGEMENT CKT, PDSO24, PLASTIC, TSSOP-24, Power Management Circuit
NSC