TC646VUA [MICROCHIP]
PWM Fan Speed Controller with Auto-Shutdown and FanSense⑩ Technology; PWM风扇速度控制器，自动关闭和FanSense⑩技术
| 型号： | TC646VUA |
| 厂家： | 
MICROCHIP |
| 描述： | PWM Fan Speed Controller with Auto-Shutdown and FanSense⑩ Technology |
| 文件： | 总28页 (文件大小：458K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
TC646
M
PWM Fan Speed Controller with Auto-Shutdown
and FanSense™ Technology
Features
Package Types
• Temperature Proportional Fan Speed for Acoustic
Control and Longer Fan Life
SOIC/PDIP/MSOP
• Efficient PWM Fan Drive
• 3.0V to 5.5V Supply Range:
- Fan Voltage Independent of TC646
Supply Voltage
V
V
V
1
2
3
4
8
7
6
5
IN
DD
C
OUT
F
TC646
V
FAULT
SENSE
AS
GND
- Supports any Fan Voltage
• FanSense™ Fault Detection Circuits Protect
Against Fan Failure and Aid System Testing
General Description
• Shutdown Mode for "Green" Systems
• Supports Low Cost NTC/PTC Thermistors
• Space Saving 8-Pin MSOP Package
• Over-temperature Indication
The TC646 is a switch mode, fan speed controller for
use with brushless DC fans. Temperature proportional
speed control is accomplished using pulse width mod-
ulation (PWM). A thermistor (or other voltage output
temperature sensor) connected to the V input fur-
IN
Applications
• Power Supplies
• Computers
• File Servers
• Portable Computers
• Telecom Equipment
• UPS, Power Amps
• General Purpose Fan Speed Control
nishes the required control voltage of 1.25V to 2.65V
(typical) for 0% to 100% PWM duty cycle. The TC646
automatically suspends fan operation when measured
temperature (V ) is below a user programmed
IN
minimum setting (V ). An integrated Start-up Timer
AS
ensures reliable motor start-up at turn-on, coming out
of shutdown mode, auto-shutdown mode or following a
transient fault.
The TC646 features Microchip Technology's propri-
etary FanSense™ technology for increasing system
reliability. In normal fan operation, a pulse train is
present at SENSE (Pin 5). A missing-pulse detector
monitors this pin during fan operation. A stalled, open,
or unconnected fan causes the TC646 to trigger its
Start-up Timer once. If the fault persists, the FAULT
output goes low and the device is latched in its shut-
down mode. FAULT is also asserted if the PWM
reaches 100% duty cycle, indicating a possible thermal
runaway situation, although the fan continues to run.
See Section 5.0, “Typical Applications”, for more
information and system design guidelines.
Available Tools
• Fan Controller Demonstration Board (TC642DEMO)
• Fan Controller Evaluation Kit (TC642EV)
The TC646 is available in the 8-pin plastic DIP, SOIC
and MSOP packages and is available in the industrial
and extended commercial temperature ranges.
2002 Microchip Technology Inc.
DS21446C-page 1
TC646
Functional Block Diagram
V
IN
+
V
DD
V
OTF
–
OTF
–
+
PWM
Control
Logic
V
OUT
C
F
3 x T
PWM
Timer
Clock
Generator
–
FAULT
Start-up
Timer
V
AS
+
–
SHDN
Missing
Pulse
Detect.
+
+
TC646
V
SHDN
–
SENSE
10kΩ
GND
70mV (typ.)
DS21446C-page 2
2002 Microchip Technology Inc.
TC646
*Stresses above those listed under "Absolute Maximum Rat-
ings" may cause permanent damage to the device. These are
stress ratings only and functional operation of the device at
these or any other conditions above those indicated in the
operation sections of the specifications is not implied. Expo-
sure to absolute maximum rating conditions for extended peri-
ods may affect device reliability.
1.0
ELECTRICAL
CHARACTERISTICS
Absolute Maximum Ratings*
Supply Voltage ......................................................... 6V
Input Voltage, Any Pin..... (GND – 0.3V) to (V +0.3V)
DD
Package Thermal Resistance:
PDIP (R ).............................................125°C/W
θJA
SOIC (R ) ............................................155°C/W
θJA
MSOP (R ) ..........................................200°C/W
θJA
Specified Temperature Range ........... -40°C to +125°C
Storage Temperature Range.............. -65°C to +150°C
DC ELECTRICAL SPECIFICATIONS
Electrical Characteristics: Unless otherwise specified, TMIN ≤ TA ≤ TMAX, VDD = 3.0V to 5.5V
Symbol
VDD
IDD
Parameter
Supply Voltage
Supply Current, Operating
Min
Typ
Max
Units
Test Conditions
3.0
—
—
0.5
5.5
1.0
V
mA Pins 6, 7 Open,
CF = 1 µF, VIN = VC(MAX)
IDD(SHDN)
Supply Current, Shutdown/
Auto-shutdown Mode
—
25
—
—
µA Pins 6, 7 Open;
Note 1
CF =1 µF, VIN = 0.35V
µA Note 1
IIN
VIN, VAS Input Leakage
-1.0
+1.0
VOUT Output
tR
tF
tSHDN
VOUT Rise Time
VOUT Fall Time
Pulse Width(On VIN) to Clear
Fault Mode
—
—
30
—
—
—
50
50
—
µsec IOH = 5 mA, Note 1
µsec IOL = 1 mA, Note 1
µsec VSHDN, VHYST
Specifications,
Note 1
IOL
IOH
Sink Current at VOUT Output
Source Current at VOUT
Output
1.0
5.0
—
—
—
—
mA VOL = 10% of VDD
mA VOH = 80% of VDD
SENSE Input
VTH(SENSE)
SENSE Input Threshold
Voltage with Respect to GND
50
70
90
mV Note 1
FAULT Output
VOL
tMP
tSTARTUP
tDIAG
Output Low Voltage
Missing Pulse Detector Timer
Start-up Timer
—
—
—
—
—
0.3
—
—
—
V
IOL = 2.5 mA
32/F
32/F
3/F
Sec CF = 1.0 µF
Sec CF = 1.0 µF
Sec CF = 1.0 µF
Diagnostic Timer
Note 1: Ensured by design, not tested.
2002 Microchip Technology Inc.
DS21446C-page 3
TC646
DC ELECTRICAL SPECIFICATIONS (CONTINUED)
Electrical Characteristics: Unless otherwise specified, TMIN ≤ TA ≤ TMAX, VDD = 3.0V to 5.5V
Symbol
Parameter
Min
Typ
Max
Units
Test Conditions
VIN, VAS Inputs
VC(MAX),VOTF Voltage at VIN for 100% Duty
Cycle and Overtemp. Fault
2.5
1.3
VC(MAX) ~
VC(SPAN)
2.65
2.8
V
VC(SPAN)
VAS
VC(MAX) - VC(MIN)
Auto-shutdown Threshold
1.4
—
1.5
VC(MAX)
V
V
VSHDN
VREL
Voltage Applied to VIN to
ensure Reset/Shutdown
Voltage Applied to VIN to
Release Reset Mode
—
—
—
VDD x 0.13
—
V
V
VDD x 0.19
VDD = 5V,
See Figure 5-11
VHYST
VHAS
Hysteresis on VSHDN, VREL
Hysteresis on Auto-shutdown
Comparator
—
—
0.01 x VDD
70
—
—
V
mV
Pulse Width Modulator
FOSC
PWM Frequency
26
30
34
Hz CF = 1.0 µF
Note 1: Ensured by design, not tested.
DS21446C-page 4
2002 Microchip Technology Inc.
TC646
2.3
Analog Input (V
)
2.0
PIN DESCRIPTIONS
AS
An external resistor divider connected to the V input
The descriptions of the pins are listed in Table 2-1.
AS
sets the auto-shutdown threshold. Auto-shutdown
occurs when V ≤ V . The fan is automatically
IN
AS
TABLE 2-1:
Pin No. Symbol
PIN FUNCTION TABLE
Description
V Analog Input
IN
restarted when V ≥ (V + V ) (see Section 5.0,
HAS
IN
AS
“Typical Applications”, for more details).
1
2
3
4
5
6
7
8
2.4
Ground (GND)
C
Analog Output
Analog Input
F
GND denotes the ground terminal.
V
AS
GND
Ground Terminal
2.5
Analog Input (SENSE)
SENSE Analog Input
FAULT Digital (Open Collector) Output
Pulses are detected at the SENSE pin as fan rotation
chops the current through a sense resistor (R ).
SENSE
V
Digital Output
OUT
The absence of pulses indicates
a fault (see
V
Power Supply Input
Section 5.0, “Typical Applications”, for more details).
DD
2.1
Analog Input (V )
2.6
Digital Output (FAULT)
IN
The thermistor network (or other temperature sensor)
The FAULT line goes low to indicate a fault condition.
When FAULT goes low due to a fan fault condition, the
device is latched in shutdown mode until deliberately
cleared or until power is cycled. FAULT will also be
asserted when the PWM reaches 100% duty cycle,
indicating that maximum cooling capability has been
reached and a possible over-temperature condition
may occur. This is a non-latching state and the FAULT
output will go high when the PWM duty cycle goes
below 100%.
connects to the V input. A voltage range of 1.25V to
IN
2.65V (typical) on this pin drives an active duty cycle of
0% to 100% on the V
pin. The TC646 enters shut-
OUT
down mode when V ≤ V
. During shutdown, the
SHDN
IN
FAULT output is inactive, and supply current falls to
25 µA (typical). The TC646 exits shutdown mode
when V ≥ V
(see Section 5.0, “Typical
REL
IN
Applications”, for details).
2.2
Analog Output (C )
F
2.7
Digital Output (V
)
OUT
is an active high complimentary output that drives
C is the positive terminal for the PWM ramp generator
F
V
timing capacitor. The recommended C is 1 µF for
F
OUT
30 Hz PWM operation.
the base of an external NPN transistor (via an appropri-
ate base resistor) or the gate of an N-channel MOS-
FET. This output has asymmetrical drive (see
Section 1.0, “Electrical Characteristics”).
2.8
Power Supply Input (V
)
DD
may be independent of the fan’s power supply
V
DD
(see Section 1.0, “Electrical Characteristics”).
2002 Microchip Technology Inc.
DS21446C-page 5
TC646
3.5
FAULT Output
3.0
DETAILED DESCRIPTION
The TC646 detects faults in two ways:
3.1
PWM
First, pulses appearing at SENSE due to the PWM
turning on are blanked, with the remaining pulses being
filtered by a missing pulse detector. If consecutive
pulses are not detected for thirty-two PWM cycles
The PWM circuit consists of a ramp generator and
threshold detector. The frequency of the PWM is
determined by the value of the capacitor connected to
the C input. A frequency of 30 Hz is recommended
F
( 1 Sec if C = 1 µF), the Diagnostic Timer is activated
F
(C = 1 µF). The PWM is also the time base for the
F
and V
is driven high continuously for three PWM
OUT
Start-up Timer (see Section 3.3, “Start-Up Timer”). The
PWM voltage control range is 1.25V to 2.65V (typical)
for 0% to 100% output duty cycle.
cycles ( 100 msec if C = 1 µF). If a pulse is not
F
detected within this window, the Start-up Timer is trig-
gered (see Section 3.3, “Start-up Timer”). This should
clear a transient fault condition. If the missing pulse
detector times out again, the PWM is stopped and
FAULT goes low. When FAULT is activated due to this
condition, the device is latched in shutdown mode and
will remain off indefinitely. Therefore, the TC646 is pre-
vented from attempting to drive a fan under cata-
strophic fault conditions.
3.2
The V
VOUT Output
pin is designed to drive a low cost transistor
OUT
or MOSFET as the low side, power switching element
in the system. Various examples of driver circuits will be
shown throughout this data sheet. This output has
asymmetric complementary drive and is optimized for
driving NPN transistors or N-channel MOSFETs. Since
the system relies on PWM rather than linear control,
the power dissipation in the power switch is kept to a
minimum. Generally, very small devices (TO-92 or SOT
packages) will suffice.
One of two things will restore operation: Cycling power
off and then on again or pulling V below V
and
SHDN
IN
releasing it to a level above V
. When one of these
REL
two conditions is satisfied, the normal start-up cycle is
triggered and operation will resume if the fault has been
cleared.
3.3
Start-Up Timer
The second condition by which the TC646 asserts a
FAULT is when the PWM control voltage applied to V
To ensure reliable fan start-up, the Start-up Timer turns
IN
becomes greater than that needed to drive 100% duty
cycle (see Section 1.0, “Electrical Characteristics”).
This indicates that the fan is at maximum drive and the
potential exists for system overheating. Either heat dis-
sipation in the system has gone beyond the cooling
system’s design limits or some subtle fault exists (such
as fan bearing failure or an airflow obstruction). This
output may be treated as a “System Overheat” warning
and be used to trigger system shutdown or some other
corrective action.
the V
output on for 32 cycles of the PWM whenever
OUT
the fan is started from the off state. This occurs at
power-up and when coming out of shutdown or auto-
shutdown mode. If the PWM frequency is 30 Hz
(C = 1 µF), the resulting start-up time will be approxi-
F
mately one second. If a fan fault is detected, the Diag-
nostic Timer is triggered once, followed by the Start-up
Timer. If the fault persists, the device is shut down (see
Section 3.5, “FAULT Output”).
3.4
SENSE Input
However, in this case, the fan will continue to run even
(FanSense™ Technology)
when FAULT is asserted. If the system is allowed to
continue operation, and the temperature (and thus V )
IN
IN
The SENSE input (Pin 5) is connected to a low value
current sensing resistor in the ground return leg of the
fan circuit. During normal fan operation, commutation
occurs as each pole of the fan is energized. This
causes brief interruptions in the fan current, seen as
pulses across the sense resistor. If the device is not in
auto-shutdown or shutdown mode, and pulses are not
appearing at the SENSE input, a fault exists.
falls, the FAULT output will become inactive when V
< V
.
OTF
3.6
Auto-Shutdown Mode
If the voltage on V becomes less than the voltage on
IN
V
, the fan is automatically shut off (auto-shutdown
AS
mode). The TC646 exits auto-shutdown mode when
the voltage on V becomes higher than the voltage on
IN
The short, rapid change in fan current (high dI/dt)
causes a corresponding dV/dt across the sense
V
by V
(the auto-shutdown Hysteresis Voltage
HAS
AS
(see Figure 3-1)). The Start-up Timer is triggered and
normal operation is resumed upon exiting auto-shut-
down mode. The FAULT output is unconditionally
inactive in auto-shutdown mode.
resistor,
R
.
The waveform on
R
is
SENSE
SENSE
differentiated and converted to a logic-level pulse-train
by C
and the internal signal processing circuitry.
SENSE
The presence and frequency of this pulse-train is a
direct indication of fan operation. See Section 5.0,
“Typical Applications”, for more details.
DS21446C-page 6
2002 Microchip Technology Inc.
TC646
Normal
Operation
TC646
Status
Normal
Operation
Auto-Shutdown
Mode
Shut-
Down
Normal
Operation
HI
2.6V
V
+ V
V
AS
HAS
AS
TEMP.
1.2V
REL
t
RESET
V
IN
V
V
SHDN
LO
GND
Time
FIGURE 3-1:
TC646 Nominal Operation.
If a fan fault has occurred and the device has latched
itself into shutdown mode, performing a reset will not
3.7 Shutdown Mode (Reset)
If an unconditional shutdown and/or device reset is
desired, the TC646 may be placed in shutdown mode
clear the fault unless V > (V + V
). If V is not
IN
IN
AS
HAS
greater than (V + V
) upon exiting shutdown
HAS
AS
by forcing V to a logic low (i.e., V < V ) (see
SHDN
IN
IN
mode, the fan will not be restarted. Consequently, there
is no way to establish that the fan fault has been
cleared. To ensure that a complete reset takes place,
Figure 3-1). In this mode, all functions cease and the
FAULT output is unconditionally inactive. The TC646
should not be shut down unless all heat producing
activity in the system is at a negligible level. The TC646
the user’s circuitry must ensure that V > (V + V )
HAS
IN
AS
when the device is released from shutdown mode. A
recommended algorithm for management of the TC646
by a host microcontroller or other external circuitry is
given in Section 5.0, “Typical Applications”. A small
exits shutdown mode when V becomes greater than
IN
V
, the release voltage.
REL
Entering shutdown mode also performs a complete
device reset. Shutdown mode resets the TC646 into its
power-up state. The Start-up and Fault Timers, and any
current faults, are cleared. FAULT is unconditionally
inactive in shutdown mode. Upon exiting shutdown
amount of hysteresis, typically one percent of V
DD
(50 mV at V = 5.0V), is designed into the V
/
SHDN
DD
V
V
threshold. The levels specified for V
and
SHDN
REL
REL
in Section 1.0, “Electrical Characteristics”,
include this hysteresis plus adequate margin to
account for normal variations in the absolute value of
the threshold and hysteresis.
mode (V > V
), the Start-up Timer will be triggered
IN
REL
and normal operation will resume, assuming no fault
conditions exist and V > V + V
IN
AS
HAS
CAUTION: Shutdown mode is unconditional. That is,
Note: If V < V when the device exits shutdown
IN
AS
the fan will remain off as long as the V pin is being
mode, the fan will not restart as it will be in auto-shut-
down mode.
IN
held low or V < V + V .
HAS
IN
AS
2002 Microchip Technology Inc.
DS21446C-page 7
TC646
4.3
Fan Fault
4.0
SYSTEM BEHAVIOR
Fan fault is an infinite loop wherein the TC646 is
The flowcharts describing the TC646’s behavioral
algorithm are shown in Figure 4-1. They can be
summarized as follows:
latched in shutdown mode. This mode can only be
released by a reset (i.e., V being brought below
IN
HAS
V
, then above (V + V
), or by power-cycling).
SHDN
AS
4.1
Power-Up
(1) While in this state, FAULT is latched on (low) and
the V output is disabled.
OUT
(1) Assuming the device is not being held in auto-shut-
down mode (V > V )..........
(2) A reset sequence applied to the V pin will exit the
IN
AS
IN
loop to Power-up.
(3) End.
(2) Turn V
output on for 32 cycles of the PWM
OUT
clock. This ensures that the fan will start from a
dead stop.
(3) During this Start-up Timer, if a fan pulse is
detected, branch to Normal Operation; if none are
received…
(4) Activate the 32-cycle Start-up Timer one more time
and look for fan pulse; if a fan pulse is detected,
proceed to Normal Operation; if none are
received…
(5) Proceed to Fan Fault.
(6) End.
4.2
Normal Operation
“Normal Operation” is an endless loop which may only
be exited by entering shutdown mode, auto-shutdown
mode or Fan Fault. The loop can be thought of as
executing at the frequency of the oscillator and PWM.
(1) Reset the missing pulse detector.
(2) Is the TC646 in shutdown or auto-shutdown
mode?
If so...
a. V
duty cycle goes to zero.
OUT
b. FAULT is disabled.
c. Exit the loop and wait for V > (V + V ) to
HAS
IN
AS
resume operation.
(3) If an over-temperature fault occurs (V > V
),
OTF
IN
activate FAULT; release FAULT when
V < V
.
IN
OTF
(4) Drive V
to a duty cycle proportional to V on
IN
OUT
a cycle by cycle basis.
(5) If a fan pulse is detected, branch back to the
start of the loop (1).
(6) If the missing pulse detector times out …
(7) Activate the 3-cycle Diagnostic Timer and look
for pulses; if a fan pulse is detected, branch
back to the start of the loop (1); if none are
received…
(8) Activate the 32-cycle Start-up Timer and look for
pulses; if a fan pulse is detected, branch back to
the start of the loop (1); if none are received…
(9) Quit Normal Operation and go to Fan Fault.
(10) End.
DS21446C-page 8
2002 Microchip Technology Inc.
TC646
Normal
Operation
Power-Up
Clear Missing
Pulse Detector
Power-on
Reset
FAULT = 1
Yes
Shutdown
= 0
V
< V
?
SHDN
IN
V
OUT
Yes
Shutdown
= 0
V
< V ?
SHDN
IN
No
V
OUT
No
V
V
REL
>
?
IN
No
V
> V
REL
No
IN
Yes
Yes
Auto
Shutdown
Yes
Power-Up
Auto-
Shutdown
OUT = 0
V
< V
> V
?
AS
IN
Yes
V
= 0
OUT
V
< V ?
AS
IN
V
No
No
V
>
)
HAS
No
IN
+ V
Yes
(V
AS
V
>
No
V
?
OTF
IN
+ V
IN
(V
)
AS
HAS
Yes
No
Hot Start
FAULT = 0
Yes
Hot Start
V
OUT
Proportional
to V
Fire Start-up
Timer
(1 SEC)
IN
Yes
No
No
Fire Start-up
Timer
(1 SEC)
Fan Pulse
Detected?
Fan Pulse
Detected?
M.P.D.
Expired?
Yes
No
Yes
Yes
Fan Pulse
Detected?
Fire
Diagnostic
Timer
(100msec)
No
Normal
Operation
Fan Fault
No
Yes
Fire Start-up
Timer
(1 sec)
Fan Pulse
Detected?
Fan Fault
Yes
Fan Pulse
Detected?
FAULT = 0,
V
= 0
OUT
No
Fan Fault
No
Auto-Shutdown
FAULT = 1
No
Cycling
Power
V
< V
?
IN
SHDN
V
= 0
OUT
Yes
Yes
Yes
No
V
> V
REL
?
V
> (V + V
)?
HAS
IN
IN
AS
No
Yes
Power-Up
FIGURE 4-1:
TC646 Behavioral Algorithm Flowchart.
2002 Microchip Technology Inc.
DS21446C-page 9
TC646
The TC642 demonstration and prototyping board
(TC642DEMO) and the TC642 Evaluation Kit
(TC642EV) provide working examples of TC646 cir-
cuits and prototyping aids. The TC642DEMO is a
printed circuit board optimized for small size and ease
of inclusion into system prototypes. The TC642EV is a
larger board intended for benchtop development and
analysis. At the very least, anyone contemplating a
design using the TC646 should consult the documen-
tation for both TC642EV (DS21403) and TC642DEMO
(DS21401). Figure 5-1 shows the base schematic for
the TC642DEMO.
5.0
TYPICAL APPLICATIONS
Designing with the TC646 involves the following:
(1) The temperature sensor network must be
configured to deliver 1.25V to 2.65V on V for 0%
IN
to 100% of the temperature range to be regulated.
(2) The auto-shutdown temperature must be set
with a voltage divider on V
.
AS
(3) The output drive transistor and associated circuitry
must be selected.
(4) The SENSE network, R
and C
, must
SENSE
SENSE
be designed for maximum efficiency while
delivering adequate signal amplitude.
(5) If shutdown capability is desired, the drive require-
ments of the external signal or circuit must be
considered.
+5V*
C
+12V
B
1µF
NTC
R
1
8
Fan
Q
1
Shutdown**
V
V
DD
IN
C
B
0.01µF
6
R
2
Thermal
Shutdown
FAULT
1
+5V
R
BASE
TC646
7
5
V
R
OUT
3
3
V
C
AS
C
B
0.01µF
SENSE
2
C
SENSE
R
F
4
R
SENSE
C
1µF
GND
4
F
NOTES: *See cautions regarding latch-up considerations in Section 5.0, "Typical Applications".
**Optional. See Section 5.0, "Typical Applications", for details.
FIGURE 5-1:
Typical Application Circuit.
DS21446C-page 10
2002 Microchip Technology Inc.
TC646
EQUATION
5.1
Temperature Sensor Design
V
x R
2
DD
The temperature signal connected to V must output a
IN
= V(T )
1
voltage in the range of 1.25V to 2.65V (typical) for 0%
to 100% of the temperature range of interest. The
circuit in Figure 5-2 illustrates a convenient way to
provide this signal.
R
(T ) + R
1 2
TEMP
V
x R
2
DD
= V(T )
2
R
(T ) + R
2 2
TEMP
V
DD
Where T and T are the chosen temperatures and
1
2
R
is the parallel combination of the thermistor
TEMP
and R .
1
I
DIV
These two equations facilitate solving for the two
unknown variables, R and R . More information about
1
2
thermistors may be obtained from AN679, “Tempera-
ture Sensing Technologies”, and AN685, “Thermistors
In Single Supply Temperature Sensing Circuits”, which
can be downloaded from Microchip’s web site at
www.microchip.com.
RT
R = 100 kΩ
1
1
NTC Thermistor
100 kΩ@25˚C
V
IN
5.2
Auto-Shutdown Temperature
Design
R = 23.2kΩ
2
A voltage divider on V sets the temperature where
AS
the part is automatically shut down if the sensed
FIGURE 5-2:
Temperature Sensing
temperature at V drops below the set temperature at
IN
Circuit.
V
(i.e., V < V ). As with the V input, 1.25V to
IN AS IN
AS
2.65V corresponds to the temperature range of interest
from T to T , respectively. Assuming that the
Figure 5-2 shows a simple temperature dependent
voltage divider circuit. RT is a conventional NTC ther-
1
2
1
temperature sensor network designed above is linearly
mistor, while R and R are standard resistors. The
1
2
related to temperature, the shutdown temperature T
supply voltage, V , is divided between R and the
AS
DD
2
is related to T and T by:
parallel combination of RT and R . For convenience,
2
1
1
1
the parallel combination of RT and R will be referred
1
1
to as R
. The resistance of the thermistor at various
EQUATION
TEMP
temperatures is obtained from the manufacturer’s
specifications. Thermistors are often referred to in
terms of their resistance at 25°C.
V
T
- 1.25V
- T
AS
2.65V - 1.25V
T - T
=
AS
1
2
1
1.4V
Generally, the thermistor shown in Figure 5-2 is a non-
)
V
=
(
( T - T ) + 1.25V
AS 1
linear device with a negative temperature coefficient
AS
T - T
2
1
(also called an NTC thermistor). In Figure 5-2, R is
1
used to linearize the thermistor temperature response
For example, if 1.25V and 2.65V at V corresponds to
IN
and R is used to produce a positive temperature
a temperature range of T = 0°C to T = 125°C, and the
2
1
2
coefficient at the V node. As an added benefit, this
auto-shutdown temperature desired is 25°C, then V
voltage is:
IN
AS
configuration produces an output voltage delta of 1.4V,
which is well within the range of the V
C(SPAN)
specification of the TC646. A 100 kΩ NTC thermistor is
EQUATION
selected for this application in order to keep I
minimum.
at a
DIV
1.4V
V
=
(25 - 0) + 1.25V = 1.53V
AS
(125 - 0)
For the voltage range at V to be equal to 1.25V to
IN
2.65V, the temperature range of this configuration is
0°C to 50°C. If a different temperature range is required
The V voltage may be set using a simple resistor
divider as shown in Figure 5-3.
AS
from this circuit, R should be chosen to equal the
1
resistance value of the thermistor at the center of this
new temperature range. It is suggested that a maxi-
mum temperature range of 50°C be used with this cir-
cuit due to thermistor linearity limitations. With this
change, R is adjusted according to the following
2
equations:
2002 Microchip Technology Inc.
DS21446C-page 11
TC646
5.3
Operations at Low Duty Cycle
V
DD
One boundary condition which may impact the selec-
tion of the minimum fan speed is the irregular activation
of the Diagnostic Timer due to the TC646 “missing” fan
commutation pulses at low speeds. This is a natural
consequence of low PWM duty cycles (typically 25% or
less). Recall that the SENSE function detects commu-
tation of the fan as disturbances in the current through
R
R
1
I
IN
R
. These can only occur when the fan is ener-
I
V
AS
SENSE
DIV
gized (i.e., V
is “on”). At very low duty cycles, the
OUT
V
output is “off” most of the time. The fan may be
OUT
rotating normally, but the commutation events are
occurring during the PWM’s off-time.
2
The phase relationship between the fan’s commutation
and the PWM edges tends to “walk around” as the
system operates. At certain points, the TC646 may fail
to capture a pulse within the 32-cycle missing pulse
detector window. If this happens, the 3-cycle
GND
FIGURE 5-3:
V
CIRCUIT
AS
Per Section 1.0, “Electrical Characteristics”, the leak-
Diagnostic Timer will be activated, the V
output will
OUT
age current at the V pin is no more than 1 µA. It is
AS
be active continuously for three cycles and, if the fan is
operating normally, a pulse will be detected. If all is
well, the system will return to normal operation. There
is no harm in this behavior, but it may be audible to the
user as the fan accelerates briefly when the Diagnostic
conservative to design for a divider current, I , of
DIV
100 µA. If V = 5.0V then…
DD
EQUATION
Timer fires. For this reason, it is recommended that V
be set no lower than 1.8V.
AS
5.0V
–4
I
= 1e A =
, therefore
DIV
R + R
1
2
5.4
FanSense™ Network
(RSENSE and CSENSE
5.0V
1e A
R + R =
= 50,000Ω = 50kΩ
1
2
)
–4
The FanSense network, comprised of R
and
SENSE
C
, allows the TC646 to detect commutation of
SENSE
We can further specify R and R by the condition that
1
2
™
the fan motor (FanSense technology). This network
can be thought of as a differentiator and threshold
the divider voltage is equal to our desired V . This
AS
yields:
detector. The function of R
current into a voltage. C
is to convert the fan
SENSE
SENSE
serves to AC-couple this
EQUATION
voltage signal and provide a ground-referenced input to
the SENSE pin. Designing a proper SENSE network is
V
x R
2
DD
V
=
simply a matter of scaling R
to provide the
AS
SENSE
R + R
necessary amount of gain (i.e., the current-to-voltage
conversion ratio). A 0.1 µF ceramic capacitor is
1
2
recommended for C
. Smaller values require
SENSE
Solving for the relationship between R and R results
1
2
larger sense resistors, and higher value capacitors are
bulkier and more expensive. Using a 0.1 µF capacitor
in:
results in reasonable values for R
. Figure 5-4
SENSE
EQUATION
illustrates a typical SENSE network. Figure 5-5 shows
the waveforms observed using a typical SENSE net-
work.
5 - 1.53
1.53
V
- V
AS
DD
R = R x
= R x
1
2
2
V
AS
In the case of this example, R = (2.27) R .
1
2
Substituting this relationship back into the original
equation yields the resistor values:
R = 15.3 kΩ, and
2
R = 34.7 kΩ
1
In this case, the standard values of 34.8 kΩ and
15.4 kΩ are very close to the calculated values and
would be more than adequate.
DS21446C-page 12
2002 Microchip Technology Inc.
TC646
TABLE 5-1:
Nominal Fan Current (mA)
RSENSE VS. FAN CURRENT
V
DD
R
(Ω)
SENSE
9.1
4.7
3.0
2.4
2.0
1.8
1.5
1.3
1.2
1.0
50
100
150
200
250
300
350
400
450
500
Fan
R
BASE
V
OUT
Q
1
SENSE
C
SENSE
(0.1 µF Typ.)
R
SENSE
5.5
Output Drive Transistor Selection
The TC646 is designed to drive an external transistor
or MOSFET for modulating power to the fan. This is
shown as Q in Figures 5-1, 5-4, 5-6, 5-7, 5-8 and 5-9.
1
GND
The V
pin has a minimum source current of 5 mA
OUT
FIGURE 5-4:
SENSE Network.
and a minimum sink current of 1 mA. Bipolar transistors
or MOSFETs may be used as the power switching
element, as shown in Figure 5-7. When high current
gain is needed to drive larger fans, two transistors may
be used in a Darlington configuration. These circuit
topologies are shown in Figure 5-7: (a) shows a single
NPN transistor used as the switching element; (b)
illustrates the Darlington pair; and (c) shows an N-
channel MOSFET.
Tek Run: 10.0kS/s Sample
[
T
]
One major advantage of the TC646’s PWM control
scheme versus linear speed control is that the power
dissipation in the pass element is kept very low.
Generally, low cost devices in very small packages,
such as TO-92 or SOT, can be used effectively. For
fans with nominal operating currents of no more than
200 mA, a single transistor usually suffices. Above
200 mA, the Darlington or MOSFET solution is
recommended. For the fan sensing function to work
correctly, it is imperative that the pass transistor be fully
saturated when “on”.
Waveform @ Sense Resistor
Waveform @ Sense Pin
GND
1
2
90mV
50mV
GND
T
M5.00ms
Ch1
100mV
142mV
Ch1
Ch2
100mV
FIGURE 5-5:
SENSE Waveforms.
Table 5-2 gives examples of some commonly available
transistors and MOSFETs. This table should be used
as a guide only since there are many transistors and
MOSFETs which will work just as well as those listed.
The critical issues when choosing a device to use as
Table 5-1 lists the recommended values of R
SENSE
based on the nominal operating current of the fan. Note
that the current draw specified by the fan manufacturer
may be a worst-case rating for near-stall conditions and
not the fan’s nominal operating current. The values in
Table 5-1 refer to actual average operating current. If
the fan current falls between two of the values listed,
use the higher resistor value. The end result of employ-
ing Table 5-1 is that the signal developed across the
sense resistor is approximately 450 mV in amplitude.
Q
are: (1) the breakdown voltage (V
or V
(BR)CEO DS
1
(MOSFET)) must be large enough to withstand the
highest voltage applied to the fan (Note: This will occur
when the fan is off); (2) 5 mA of base drive current must
be enough to saturate the transistor when conducting
the full fan current (transistor must have sufficient
gain); (3) the V
voltage must be high enough to suf-
OUT
ficiently drive the gate of the MOSFET to minimize the
R
of the device; (4) rated fan current draw must
DS(on)
be within the transistor's/MOSFET's current handling
capability; and (5) power dissipation must be kept
within the limits of the chosen device.
2002 Microchip Technology Inc.
DS21446C-page 13
TC646
A base-current limiting resistor is required with bipolar
transistors. This is shown in Figure 5-6.
The correct value for this resistor can be determined as
follows:
V
V
V
= V
+ V
+ V
BE R
(SAT) BASE
OH
R
SENSE
x R
V
DD
= I
R
R
FAN
SENSE
SENSE
BASE
= R
x I
BASE
BASE
/ h
FAN FE
I
= I
BASE
V
is specified as 80% of V
in Section 1.0,
is given in the
OH
DD
“Electrical Characteristics”; V
BE
(SAT)
Fan
chosen transistor data sheet. It is now possible to solve
for R
.
BASE
R
BASE
EQUATION
V
= 80% V
DD
OH
Q
1
–
+
BE
+
V
V
- V
- V
R
(SAT) SENSE
R
OH
BE
BASE
R
=
BASE
–
V
I
(SAT)
+
BASE
V
Some applications benefit from the fan being powered
from a negative supply to keep motor noise out of the
positive supply rails. This can be accomplished as
R
R
SENSE
SENSE
–
shown in Figure 5-8. Zener diode D offsets the -12V
1
power supply voltage, holding transistor Q off when
1
GND
V
is low. When V
is high, the voltage at the
OUT
OUT
anode of D increases by V
, causing Q to turn on.
1
1
OUT
FIGURE 5-6:
Circuit For Determining
Operation is otherwise the same as in the case of fan
operation from +12V.
R
.
BASE
V
V
V
DD
DD
DD
Fan
Fan
Fan
R
BASE
R
BASE
V
OUT
Q
1
V
Q
OUT
1
Q
V
1
OUT
Q
2
R
R
SENSE
SENSE
R
SENSE
GND
GND
a) Single Bipolar Transistor
GND
b) Darlington Transistor Pair
c) N-Channel MOSFET
FIGURE 5-7:
Output Drive Transistor Circuit Topologies.
DS21446C-page 14
2002 Microchip Technology Inc.
TC646
+5V
V
DD
R *
2
2.2 kΩ
V
OUT
D
12.0V
1
Fan
Zener
TC646
Q *
1
R *
4
R *
3
10 kΩ
2.2Ω
GND
-12V
NOTE: *Value depends on the specific application and is shown for example only.
FIGURE 5-8:
Power the Fan from a -12V Supply.
TABLE 5-2:
Device
TRANSISTORS AND MOSFETS FOR Q (V = 5V)
1
DD
Max. V
/V
V
/V
Fan Current
(mA)
Suggested
BE(sat) GS
CEO DS
Package
Min. H
FE
(V)
(V)
R
(Ω)
BASE
800
800
301
Note 1
Note 1
Note 1
Note 1
MMBT2222A
MPS2222A
MPS6602
SI2302
MGSF1N02E
SI4410
SOT-23
TO-92
TO-92
SOT-23
SOT-23
SO-8
1.2
1.2
1.2
2.5
2.5
4.5
4.5
50
50
50
NA
NA
NA
NA
40
40
40
20
20
30
60
150
150
500
500
500
1000
500
SI2308
SOT-23
Note 1: A series gate resistor may be used in order to control the MOSFET turn-on and turn-off times.
5.6
Latch-up Considerations
5.7
Power Supply Routing and
Bypassing
As with any CMOS IC, the potential exists for latch-up
if signals are applied to the device which are outside
the power supply range. This is of particular concern
during power-up if the external circuitry (such as the
Noise present on the V and V inputs may cause
IN
AS
erroneous operation of the FAULT output. As a result,
these inputs should be bypassed with a 0.01 µF
capacitor mounted as close to the package as possible.
sensor network, V
divider or shutdown circuit) is
AS
powered by a supply different from that of the TC646.
This is especially true of V , which is usually driven
IN
Care should be taken to ensure that the TC646’s V
from a high impedance source (such as a thermistor).
DD
supply powers up first. If possible, the networks
attached to V and V should connect to the V sup-
In addition, the V
input should be bypassed with a
DD
1 µF capacitor. Grounds should be kept as short as
possible. To keep fan noise off the TC646 ground pin,
individual ground returns for the TC646 and the low
side of the fan current sense resistor should be used.
IN
AS
DD
ply at the same physical location as the IC itself. Even
if the IC and any external networks are powered by the
same supply, physical separation of the connecting
points can result in enough parasitic capacitance and/
or inductance in the power supply connections to delay
one power supply “routing” versus another.
2002 Microchip Technology Inc.
DS21446C-page 15
TC646
Design Example
Step 1. Calculate R and R based on using an NTC
1
2
having a resistance of 10 kΩ at T
(25°C)
MIN
and 4.65 kΩ at T
(45°C) (See Figure 5-9).
MAX
R = 20.5 kΩ
1
R = 3.83 kΩ
2
Step 2. Set auto-shutdown level V = 1.8V.
AS
Limit the divider current to 100 µA from which
R = 33 kΩ
5
R = 18 kΩ
6
Step 3. Design the output circuit.
Maximum fan motor current = 250 mA. Q
1
beta is chosen at 50 from which R = 800 Ω.
7
+5V
+12V
+5V
NTC
10 kΩ
@ 25˚C
C
1 µF
B
R
1
Open-Drain
Device
20.5 kΩ
4
8
Fan
Q
Reset
Shutdown
1
V
V
DD
GND
IN
C
B
0.01 µF
R
2
3.83 kΩ
6
Fan/Thermal
Fault
FAULT
1
(Optional)
R
+5V
7
800Ω
TC646
7
5
V
R
33 kΩ
OUT
5
3
V
C
AS
C
B
SENSE
0.01 µF
2
C
SENSE
0.1 µF
R
6
18 kΩ
F
R
SENSE
2.2Ω
C
1
1 µF
FIGURE 5-9:
Design Example.
With V set at 1.8V, the TC646 enters auto-shutdown
5.8
TC646 as a Microcontroller
Peripheral
AS
when the controller's output code is 000[B]. Output
codes 001[B] to 111[B] operate the fan from roughly
40% to 100% of full speed. An open-drain output from
the processor (I/O0) can be used to reset the TC646
following detection of a fault condition. The FAULT out-
put can be connected to the controller's interrupt input,
or to another I/O pin, for polled operation.
In a system containing a microcontroller or other host
intelligence, the TC646 can be effectively managed as
a CPU peripheral. Routine fan control functions can be
performed by the TC646 without controller intervention.
The microcontroller receives temperature data from
one or more points throughout the system. It calculates
a fan operating speed based on an algorithm specifi-
cally designed for the application at hand. The proces-
sor controls fan speed using complementary port bits
I/O1 through I/O3. Resistors R through R (5% toler-
1
6
ance) form a crude 3-bit DAC that translates the 3-bit
code from the processor's outputs into a 1.6V DC con-
trol signal. A monolithic DAC or digital pot may be used
instead of the circuit shown in Figure 5-10.
DS21446C-page 16
2002 Microchip Technology Inc.
TC646
+12V
+5V
(RESET)
Open-Drain
Outputs
(Optional)
I/O0
+5V
Fan
R
1
110 kΩ
1
2
8
(MSB)
V
C
V
I/O1
I/O2
I/O3
IN
DD
+
C
B
C
R
2
240 kΩ
B
Analog or Digital
Temperature
Data from one or
more Sensors
1 µF
R
800Ω
.01 µF
CMOS
Outputs
9
7
R
3
360 kΩ
F
V
OUT
2N2222A
+
+5V
TC646
1 µF
R
7
33 kΩ
(LSB)
+5V
R
10
10 kΩ
CMOS
R
4
3
6
5
R
V
AS
18 k
5
Ω
FAULT
Microcontroller
C
B
+5V
1.5 kΩ
R
18 kΩ
8
.01 µF
0.1 µF
4
R
6
SENSE
GND
1 kΩ
R
11
2.2Ω
GND
INT
FIGURE 5-10:
TC646 as a Microcontroller Peripheral.
V
vs.Temperature
RELEASE
1.0
0.9
V
= 5.5V
= 5.0V
DD
V
DD
0.8
0.7
V
DD
= 4.0V
0.6
V
= 3.0V
DD
0.5
0.4
0˚C
25˚C
TEMPERATURE
85˚C
FIGURE 5-11:
VRELEASE vs. Temperature.
2002 Microchip Technology Inc.
DS21446C-page 17
TC646
6.0
6.1
PACKAGING INFORMATION
Package Marking Information
8-Lead PDIP (300 mil)
Example:
XXXXXXXX
NNN
TC646VPA
025
YYWW
0215
8-Lead SOIC (150 mil)
Example:
XXXXXXXX
YYWW
TC646VOA
0215
NNN
025
Example:
8-Lead MSOP
TC646E
XXXXXX
YWWNNN
215025
Legend: XX...X Customer specific information*
YY
WW
NNN
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code
Note:
In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line thus limiting the number of available characters
for customer specific information.
*
Standard marking consists of Microchip part number, year code, week code, traceability code (facility
code, mask rev#, and assembly code). For marking beyond this, certain price adders apply. Please check
with your Microchip Sales Office.
DS21446C-page 18
2002 Microchip Technology Inc.
TC646
8-Lead Plastic Dual In-line (P) – 300 mil (PDIP)
E1
D
2
n
1
α
E
A2
A
L
c
A1
β
B1
B
p
eB
Units
Dimension Limits
INCHES*
NOM
MILLIMETERS
MIN
MAX
MIN
NOM
8
MAX
n
p
A
A2
A1
E
E1
D
L
c
B1
B
Number of Pins
Pitch
Top to Seating Plane
Molded Package Thickness
Base to Seating Plane
Shoulder to Shoulder Width
Molded Package Width
Overall Length
Tip to Seating Plane
Lead Thickness
Upper Lead Width
Lower Lead Width
Overall Row Spacing
Mold Draft Angle Top
Mold Draft Angle Bottom
8
.100
.155
.130
2.54
3.94
3.30
.140
.170
.145
3.56
2.92
4.32
3.68
.115
.015
.300
.240
.360
.125
.008
.045
.014
.310
5
0.38
7.62
6.10
9.14
3.18
0.20
1.14
0.36
7.87
5
.313
.250
.373
.130
.012
.058
.018
.370
10
.325
.260
.385
.135
.015
.070
.022
.430
15
7.94
6.35
9.46
3.30
0.29
1.46
0.46
9.40
10
8.26
6.60
9.78
3.43
0.38
1.78
0.56
10.92
15
§
eB
α
β
5
10
15
5
10
15
* Controlling Parameter
§ Significant Characteristic
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MS-001
Drawing No. C04-018
2002 Microchip Technology Inc.
DS21446C-page 19
TC646
8-Lead Plastic Small Outline (SN) – Narrow, 150 mil (SOIC)
E
E1
p
D
2
B
n
1
h
α
45×
c
A2
A
f
β
L
A1
Units
INCHES*
NOM
MILLIMETERS
Dimension Limits
MIN
MAX
MIN
NOM
8
MAX
n
p
A
A2
A1
E
E1
D
h
L
f
Number of Pins
Pitch
Overall Height
8
.050
.061
.056
.007
.237
.154
.193
.015
.025
4
1.27
.053
.069
1.35
1.32
1.55
1.42
0.18
6.02
3.91
4.90
0.38
0.62
4
1.75
Molded Package Thickness
Standoff
.052
.004
.228
.146
.189
.010
.019
0
.061
.010
.244
.157
.197
.020
.030
8
1.55
0.25
6.20
3.99
5.00
0.51
0.76
8
§
0.10
5.79
3.71
4.80
0.25
0.48
0
Overall Width
Molded Package Width
Overall Length
Chamfer Distance
Foot Length
Foot Angle
c
Lead Thickness
Lead Width
.008
.013
0
.009
.017
12
.010
.020
15
0.20
0.33
0
0.23
0.42
12
0.25
0.51
15
B
α
β
Mold Draft Angle Top
Mold Draft Angle Bottom
0
12
15
0
12
15
* Controlling Parameter
§ Significant Characteristic
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not exceed
.010” (0.254mm) per side.
JEDEC Equivalent: MS-012
Drawing No. C04-057
DS21446C-page 20
2002 Microchip Technology Inc.
TC646
8-Lead Plastic Micro Small Outline Package (MS) (MSOP)
E
p
E1
D
2
B
n
1
α
A2
A
c
φ
A1
(F)
L
β
Units
Dimension Limits
INCHES
NOM
MILLIMETERS*
NOM
MIN
MAX
MIN
MAX
8
n
p
Number of Pins
Pitch
8
.026
0.65
Overall Height
Molded Package Thickness
A
A2
A1
E
E1
D
.044
1.18
0.97
0.15
.5.08
3.10
3.10
0.70
1.00
6
.030
.034
.038
.006
.200
.122
.122
.028
.039
0.76
0.05
0.86
Standoff
§
.002
.184
.114
.114
.016
.035
Overall Width
Molded Package Width
Overall Length
Foot Length
Footprint (Reference)
Foot Angle
.193
.118
.118
.022
.037
4.90
3.00
3.00
0.55
0.95
4.67
2.90
2.90
0.40
0.90
L
F
φ
0
6
0
c
Lead Thickness
Lead Width
Mold Draft Angle Top
Mold Draft Angle Bottom
.004
.010
.006
.012
.008
.016
0.10
0.25
0.15
0.30
0.20
0.40
B
α
β
7
7
7
7
*Controlling Parameter
§ Significant Characteristic
Notes:
Dimensions D and E1 do not include mold flash or protrusions. Mold flash or protrusions shall not
exceed. 010" (0.254mm) per side.
Drawing No. C04-111
2002 Microchip Technology Inc.
DS21446C-page 21
TC646
6.2
Taping Form
Component Taping Orientation for 8-Pin MSOP Devices
User Direction of Feed
PIN 1
W
P
Standard Reel Component Orientation
for 713 Suffix Device
Carrier Tape, Number of Components Per Reel and Reel Size
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
8-Pin MSOP
12 mm
8 mm
2500
13 in
Component Taping Orientation for 8-Pin SOIC (Narrow) Devices
User Direction of Feed
PIN 1
W
P
Standard Reel Component Orientation
for 713 Suffix Device
Carrier Tape, Number of Components Per Reel and Reel Size
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
8-Pin SOIC (N)
12 mm
8 mm
2500
13 in
DS21446C-page 22
2002 Microchip Technology Inc.
TC646
ON-LINE SUPPORT
Microchip provides on-line support on the Microchip
World Wide Web site.
SYSTEMS INFORMATION AND
UPGRADE HOT LINE
The Systems Information and Upgrade Line provides
system users a listing of the latest versions of all of
Microchip's development systems software products.
Plus, this line provides information on how customers
can receive the most current upgrade kits.The Hot Line
Numbers are:
1-800-755-2345 for U.S. and most of Canada, and
1-480-792-7302 for the rest of the world.
The web site is used by Microchip as a means to make
files and information easily available to customers. To
view the site, the user must have access to the Internet
®
®
and a web browser, such as Netscape or Microsoft
Internet Explorer. Files are also available for FTP
download from our FTP site.
ConnectingtotheMicrochipInternetWebSite
The Microchip web site is available at the following
URL:
092002
www.microchip.com
The file transfer site is available by using an FTP ser-
vice to connect to:
ftp://ftp.microchip.com
The web site and file transfer site provide a variety of
services. Users may download files for the latest
Development Tools, Data Sheets, Application Notes,
User's Guides, Articles and Sample Programs. A vari-
ety of Microchip specific business information is also
available, including listings of Microchip sales offices,
distributors and factory representatives. Other data
available for consideration is:
• Latest Microchip Press Releases
• Technical Support Section with Frequently Asked
Questions
• Design Tips
• Device Errata
• Job Postings
• Microchip Consultant Program Member Listing
• Links to other useful web sites related to
Microchip Products
• Conferences for products, Development Systems,
technical information and more
• Listing of seminars and events
2002 Microchip Technology Inc.
DS21446C-page23
TC646
READER RESPONSE
It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip prod-
uct. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation
can better serve you, please FAX your comments to the Technical Publications Manager at (480) 792-4150.
Please list the following information, and use this outline to provide us with your comments about this document.
To:
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Reader Response
Total Pages Sent ________
RE:
From:
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Address
City / State / ZIP / Country
Telephone: (_______) _________ - _________
FAX: (______) _________ - _________
Application (optional):
Would you like a reply?
Y
N
Literature Number:
DS21446C
Device:
TC646
Questions:
1. What are the best features of this document?
2. How does this document meet your hardware and software development needs?
3. Do you find the organization of this document easy to follow? If not, why?
4. What additions to the document do you think would enhance the structure and subject?
5. What deletions from the document could be made without affecting the overall usefulness?
6. Is there any incorrect or misleading information (what and where)?
7. How would you improve this document?
DS21446C-page24
2002 Microchip Technology Inc.
TC646
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
PART NO.
Device
X
/XX
Examples:
Temperature Package
Range
a)
b)
c)
d)
TC646VOA: PWM Fan Speed Controller w/
Auto Shutdown and Fault Detection, SOIC
package.
TC646VUA: PWM Fan Speed Controller w/
Auto Shutdown and Fault Detection, MSOP
package.
TC646VPA: PWM Fan Speed Controller w/
Auto Shutdown and Fault Detection, PDIP
package.
TC646EOA713: PWM Fan Speed Controller
w/Auto Shutdown and Fault Detection, SOIC
package, Tape and Reel.
Device:
TC646:
PWM Fan Speed Controller w/Auto Shutdown
and Fault Detection
Temperature Range:
Package:
V
E
=
=
0°C to +85°C
-40°C to +85°C
PA
OA
UA
=
=
=
Plastic DIP (300 mil Body), 8-lead *
Plastic SOIC, (150 mil Body), 8-lead
Plastic Micro Small Outline (MSOP), 8-lead
* PDIP package is only offerred in the V temp range
Sales and Support
Data Sheets
Products supported by a preliminary Data Sheet may have an errata sheet describing minor operational differences and recom-
mended workarounds. To determine if an errata sheet exists for a particular device, please contact one of the following:
1. Your local Microchip sales office
2. The Microchip Corporate Literature Center U.S. FAX: (480) 792-7277
3. The Microchip Worldwide Site (www.microchip.com)
Please specify which device, revision of silicon and Data Sheet (include Literature #) you are using.
New Customer Notification System
Register on our web site (www.microchip.com/cn) to receive the most current information on our products.
2002 Microchip Technology Inc.
DS21446C-page25
TC646
NOTES:
DS21446C-page 26
2002 Microchip Technology Inc.
Information contained in this publication regarding device
applications and the like is intended through suggestion only
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
No representation or warranty is given and no liability is
assumed by Microchip Technology Incorporated with respect
to the accuracy or use of such information, or infringement of
patents or other intellectual property rights arising from such
use or otherwise. Use of Microchip’s products as critical com-
ponents in life support systems is not authorized except with
express written approval by Microchip. No licenses are con-
veyed, implicitly or otherwise, under any intellectual property
rights.
Trademarks
The Microchip name and logo, the Microchip logo, KEELOQ,
MPLAB, PIC, PICmicro, PICSTART and PRO MATE are
registered trademarks of Microchip Technology Incorporated
in the U.S.A. and other countries.
FilterLab, microID, MXDEV, MXLAB, PICMASTER, SEEVAL
and The Embedded Control Solutions Company are
registered trademarks of Microchip Technology Incorporated
in the U.S.A.
dsPIC, dsPICDEM.net, ECONOMONITOR, FanSense,
FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP,
ICEPIC, microPort, Migratable Memory, MPASM, MPLIB,
MPLINK, MPSIM, PICC, PICDEM, PICDEM.net, rfPIC, Select
Mode and Total Endurance are trademarks of Microchip
Technology Incorporated in the U.S.A. and other countries.
Serialized Quick Turn Programming (SQTP) is a service mark
of Microchip Technology Incorporated in the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
© 2002, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
Microchip received QS-9000 quality system
certification for its worldwide headquarters,
design and wafer fabrication facilities in
Chandler and Tempe, Arizona in July 1999
and Mountain View, California in March 2002.
The Company’s quality system processes and
procedures are QS-9000 compliant for its
®
PICmicro 8-bit MCUs, KEELOQ® code hopping
devices, Serial EEPROMs, microperipherals,
non-volatile memory and analog products. In
addition, Microchip’s quality system for the
design and manufacture of development
systems is ISO 9001 certified.
2002 Microchip Technology Inc.
DS21446C - page 27
M
WORLDWIDE SALES AND SERVICE
Japan
AMERICAS
ASIA/PACIFIC
Microchip Technology Japan K.K.
Benex S-1 6F
Corporate Office
Australia
2355 West Chandler Blvd.
Microchip Technology Australia Pty Ltd
Suite 22, 41 Rawson Street
Epping 2121, NSW
3-18-20, Shinyokohama
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Tel: 81-45-471- 6166 Fax: 81-45-471-6122
Chandler, AZ 85224-6199
Tel: 480-792-7200 Fax: 480-792-7277
Technical Support: 480-792-7627
Web Address: http://www.microchip.com
Australia
Tel: 61-2-9868-6733 Fax: 61-2-9868-6755
Korea
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Microchip Technology Consulting (Shanghai)
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#07-02 Prime Centre
Boston
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India
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Microchip Technology Inc.
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Tel: 39-039-65791-1 Fax: 39-039-6899883
United Kingdom
Microchip Ltd.
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Wokingham
Berkshire, England RG41 5TU
Tel: 44 118 921 5869 Fax: 44-118 921-5820
08/01/02
DS21446C-page 28
2002 Microchip Technology Inc.
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