LTC1710 [Linear]
SMBus Dual Monolithic High Side Switch; SMBus的双单片高边开关
| 型号： | LTC1710 |
| 厂家： | 
Linear |
| 描述： | SMBus Dual Monolithic High Side Switch |
| 文件： | 总8页 (文件大小：223K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC1710
SMBus Dual Monolithic
High Side Switch
U
FEATURES
DESCRIPTION
The LTC®1710 SMBus dual switch has two built-in 0.4Ω/
300mA switches that are controlled by a 2-wire SMBus
interface. With a low standby current of 14µA (3.3V), the
LTC1710 operates over an input voltage range of 2.7V to
5.5Vwhile maintainingthe SMBus specified0.6V VIL and
1.4V VIH input thresholds.
■
Two 0.4
Ω/300mA N-Channel Switches
■
■
■
■
■
■
■
■
■
Available in MS8 and SO-8 Packages
SMBus and I2C Compatible
0.6V VIL and 1.4V VIH for DATA and CLK
Low Standby Current: 14µA
Separate Drain Connection to SW0
Three Addresses from One Three-State Address Pin
Independent Control of Up to Six Switches
Built-In Power-On Reset Timer
Using the 2-wire interface, CLK and DATA, the LTC1710
follows SMBus’s Send Byte Protocol to independently
control the two 0.4Ω internal N-channel power switches,
which are fully enhanced by onboard charge pumps.
Built-In Undervoltage Lockout
U
The LTC1710 has one three-state programmable
addresspinthatallowsthreedifferentaddressesforatotal
of six available switches on the same bus. The LTC1710
also features a separate user-controlled drain supply
(SW0D) to Switch 0 so that it can be used to control
SMBus peripherials using a different power supply.
APPLICATIONS
■
Handheld Computer Power Management
Computer Peripheral Control
Laptop Computer Power Plane Switching
Portable Equipment Power Control
Industrial Control Systems
ACPI SMBus Interface
■
■
■
■
, LTC and LT are registered trademarks of Linear Technology Corporation.
■
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TYPICAL APPLICATION
Switch Voltage Drop
vs Load Current
V
SW0D
0V TO V
CC
500
2.7V TO 5.5V
CC
T
= 25°C
A
8
1
400
300
200
100
0
10µF
10µF
SW0
5
2
CLOCK
LOAD 1
FROM SMBus
CHARGE
PUMP
6
3
V
CC
= 2.7V
DATA
AD1
V
CC
= 3.3V
7
V
CC
= 5V
SW1
(PROGRAMMABLE)
LOAD 2
LTC1710
200
300
0
100
400
4
1710 TA01
LOAD CURRENT (mA)
1710 TA02
1
LTC1710
W W
U W
ABSOLUTE MAXIMUM RATINGS
(Voltages Referred to GND Pin) (Note 1)
Operating Temperature Range
Input Supply Voltage (VCC).......................... –0.3V to 6V
Input Supply Voltage (VCC) with SW0 Connected
as a Low Side Switch ........................... –0.3V to 3.6V
DATA, CLK (Bus Pins 6, 5)......................... –0.3V to 6V*
AD1 ( Address Pin 3) ....................... –0.3V to VCC + 0.3V
OUT0, OUT1 (Output Pins 2, 7) ................... –0.3V to 6V
SW0D (Switch 0 Drain Pin 1)....................... –0.3V to 6V
OUT0, OUT1 (Output Pins 2, 7)
LTC1710C................................................ 0°C to 70°C
LTC1710I............................................ –40°C to 85°C
Junction Temperature** ...................................... 125°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C
*Supply rails to DATA and CLK are independent of VCC to LTC1710.
**Although the LTC1710 can sustain TJMAX = 125°C without damage, its internal protection
circuitry is set to shut down the switches at TJ = 120°C with 15°C hysteresis.
Continuous .................................................... 300mA
Pulsed, <10µs (nonrepetitive) ............................... 1A
U
W U
PACKAGE/ORDER INFORMATION
ORDER PART
ORDER PART
TOP VIEW
NUMBER
NUMBER
TOP VIEW
SW0D
OUT0
AD1
1
2
3
4
8
7
6
5
V
CC
SW0D
OUT0
AD1
1
2
3
4
8 V
CC
OUT1
DATA
CLK
LTC1710CMS8
LTC1710CS8
LTC1710IS8
7 OUT1
6 DATA
5 CLK
GND
GND
MS8 PACKAGE
8-LEAD PLASTIC MSOP
MS8 PART MARKING
LTDZ
S8 PART MARKING
S8 PACKAGE
8-LEAD PLASTIC SO
TJMAX = 110°C, θJA = 150°C/ W
1710
1710I
TJMAX = 110°C, θJA = 110°C/ W
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
TA = 25°C, VCC = SW0D = 5V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
Operating Supply Voltage Range
Supply Current
●
2.7
5.5
V
CC
I
Charge Pump Off, AD1 High or Low,
DATA and CLK High
VCC
V
CC
V
CC
V
CC
= 5V
= 3.3V
= 2.7V
●
●
●
17
14
11
30
30
30
µA
µA
µA
OUT0 or OUT1 High
(Command Byte XXXXXX01 or XXXXXX10)
Both Outputs High (Command Byte XXXXXX11)
●
●
200
250
300
500
µA
µA
R
Power Switch On Resistance
V
V
V
= 2.7V, I
= 3.3V, I
= 300mA
= 300mA
= 300mA
0.55
0.46
0.40
Ω
Ω
Ω
DS(ON)
CC
CC
CC
OUT
OUT
0.7
0.6
= 5V, I
OUT
V
Undervoltage Lockout
Falling Edge (Note 2)
●
1.5
2.0
2.5
V
UVLO
t
Power-On Reset Delay Time
V
V
= 2.7V (Note 3)
= 5.5V
300
300
1000
1000
µs
µs
POR
CC
CC
f
Charge Pump Oscillator Frequency
(Note 3)
300
kHz
OSC
2
LTC1710
ELECTRICAL CHARACTERISTICS TA = 25°C, VCC = SW0D = 5V unless otherwise noted.
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
t
Output Turn-On Time
(100Ω/1µF Load)
V
V
= 2.7V (From ON (Note 6) to V
= 5.5V (From ON (Note 6) to V
= 90% V
= 90% V
)
CC
200
160
µs
µs
ON
CC
CC
OUT
OUT
)
CC
t
Output Turn-Off Time
(100Ω/1µF Load)
V
V
= 2.7V (From OFF (Note 7) to V
= 5.5V (From OFF (Note 7) to V
= 10% V
= 10% V
)
)
250
250
µs
µs
OFF
CC
CC
OUT
OUT
CC
CC
V
V
DATA/CLK Input Low Voltage
AD1 Input Low Voltage
V
V
= 2.7V to 5.5V
= 2.7V to 5.5V
●
●
0.6
0.2
V
V
IL
CC
CC
DATA/CLK High Voltage
AD1 Input High Voltage
V
V
= 2.7V to 5.5V
= 2.7V to 5.5V
●
●
1.4
V
V
IH
CC
CC
V
– 0.2
CC
V
C
Data Output Low Voltage
V
= 2.7V to 5.5V, I = 350µA
PULL-UP
●
0.18
5
0.4
V
pF
µA
nA
OL
CC
Input Capacitance (DATA, CLK, AD1)
Input Leakage Current (DATA, CLK)
Input Leakage Current (AD1)
IN
I
●
●
±1
IN
±250
SMBus Related Specifications (Note 5)
f
t
SMBus Operating Frequency
10
100
kHz
SMB
BUF
Bus Free Time Between
Stop and Start
4.7
µs
t
t
t
t
t
t
t
t
t
I
Start Condition Setup Time
Start Condition Hold Time
Stop Condition Setup Time
Data Hold Time
4.7
4.0
4.0
300
250
4.7
4.0
µs
µs
µs
ns
ns
µs
µs
ns
ns
µA
SU:STA
HD:STA
SU:STO
HD: DAT
SU:DAT
LOW
Data Setup Time
Clock Low Period
Clock High Period
50
300
1000
350
HIGH
Clock/Data Fall Time
Clock/Data Rise Time
f
r
Current Through External Pull-Up
Resistor on DATA Pin
V
= 2.7V to 5.5V
CC
100
PULL-UP
(Open-Drain Data Pull-Down Current Capacity)
The
●
denotes specifications which apply over the full operating
Note 4: The oscillator frequency is not tested directly but is inferred from
turn-on time.
temperature range.
Note 1: Absolute Maximum Ratings are those values beyond which the life
Note 5: SMBus timing specifications are guaranteed but not tested.
of a device may be impaired.
Note 6: ON is enabled upon receiving the Stop condition from the SMBus
Note 2: Approximately 3% hysteresis is provided to ensure stable operation
master.
and eliminate false triggering by minor V glitches.
CC
Note 7: OFF is enabled upon receiving the Stop condition from the SMBus
Note 3: Measured from V > V
to SMBus ready for DATA input.
master.
CC
UVLO
3
LTC1710
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current (IQ)
vs Supply Voltage
Supply Current (IQ)
Standby Current vs Temperature
vs Temperature
500
400
300
200
100
0
50
40
30
20
10
0
500
400
300
200
100
0
T
= 25°C
A
V
= 5V
CC
BOTH SW ON
BOTH SW ON
SW1 ON
SW1 ON
SW0 ON
V
= 3.3V
CC
V
= 5V
CC
SW0 ON
V
CC
= 2.7V
0
0
2
4
6
8
50
–50
100
50
0
TEMPERATURE (°C)
–50
100
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
1710 G03
1710 G01
1710 G02
Switch RDS(ON) vs Temperature
(SO-8 Package)
Switch RDS(ON) vs Temperature
(MSOP Package)
Data ACK VOL vs Temperature
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
400
300
200
100
0
I
= 300mA
I
= 300mA
OUT
OUT
I
= 350µA
PULL-UP
V
= 2.7V
= 5V
CC
V
CC
= 2.7V
V
CC
= 3.3V
V
= 3.3V
CC
V
CC
V
CC
= 5V
–50
0
50
100
0
20
40
60
80
100
0
50
100
–50
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
1710 G04
1710 G05
1710 G06
U
U
U
PIN FUNCTIONS
SW0D (Pin 1): Drain Supply of Switch 0. User-program-
CLK (Pin 5): Serial Clock Interface. Must be pulled high to
VCC with external resistor. The pull-up current must be
limited to 350µA.
mable from 0V to VCC.
OUT0 (Pin 2): Source Output of Switch 0. Maximum load
of 300mA; controlled by LSB of command byte.
DATA (Pin 6): Open-Drain Connected Serial Data Inter-
face. Must be pulled high to VCC with external resistor. The
pull-up current must be limited to 350µA.
AD1 (Pin 3): Three-State Programmable Address Pin.
Must be connected directly to VCC, GND or VCC/2 (using
two resistors ≤1M). Do not float this pin.
OUT1 (Pin 7): Source Output of Switch 1. Maximum load
of 300mA; controlled by 2nd LSB of command byte.
GND (Pin 4): Ground Connection.
VCC (Pin 8): Input Supply Voltage. Operating range from
2.7V to 5.5V.
4
LTC1710
W
BLOCK DIAGRA
POWER-ON
RESET
UNDERVOLTAGE
LOCKOUT
V
8
CC
V
CC
2V
START
AND
STOP
DETECTORS
V
CC
ACK
DATA
CLK
6
5
SHIFT
REGISTER
INPUT
BUFFERS
LOGIC
7
1
OUT1
A
B
REGULATED
CHARGE
PUMPS
OUTPUT
LATCHES
THERMAL
SHUTDOWN
SW0D
COUNTER
2
4
OUT0
GND
ADDRESS
DECODER
ADDRESS
COMPARATOR
AD1
3
1710 BD
W U
W
TI I G DIAGRA
CLK
t
HIGH
t
t
f
t
r
HD:STA
t
SU:STO
t
LOW
t
t
HD:DAT
t
SU:DAT
SU:STA
DATA
START
STOP
1710 TD
U
OPERATIO
SMBus Operation
The protocol that the LTC1710 uses is the Send Byte Pro-
tocol. In this protocol, the master first sends out a Start
signal by switching the DATA line from high to low while
CLK is high. (Because there may be more than one master
on the same bus, an arbitration process takes place if two
masters attempt to take control of the DATA line simulta-
neously; the first master that outputs a one while the other
master is zero loses the arbitration and becomes a slave
itself.) Upon detecting this Start signal, all slave devices on
thebuswakeupandpreparetoshiftinthenextbyteofdata.
SMBusisaserialbusinterfacethatusesonlytwobuslines,
DATA and CLK, to control low power peripheral devices in
portable equipment. It consists of masters, also known as
hosts, and slave devices. The master of the SMBus is
always the one to initiate communications to the slave
devices by varying the status of the DATA and CLK lines.
TheSMBusspecificationestablishesasetofprotocolsthat
devices on the bus must follow for communications.
5
LTC1710
U
OPERATIO
The master then sends out the first byte. The first seven
bitsofthisbyteconsistoftheaddressofthedevicethatthe
master wishes to communicate with. The last bit indicates
whether the command will be a read (logic one) or write
(logic zero). Because the LTC1710 is a slave device that
canonlybewrittentobyamaster,itwillignoretheensuing
commands of the master if it wants to read from the
LTC1710, even if the address sent by the master matches
that of the LTC1710. After reception of the first byte, the
slave device (LTC1710) with the matching address then
acknowledges the master by pulling the DATA line low
before the next rising clock edge.
executed on the Stop signal despite the fact that valid data
were loaded into their output latches at different times. An
example is shown in Figure 1. If somehow either the Start
or the Stop signal is detected in the middle of a byte, the
slave device (LTC1710) will regard this as an error and
reject all previous data.
Address
The LTC1710 has an address of 10110XX; the five MSBs
are hardwired, but the two LSBs are programmable by the
user with the help of a three-state address pin. Refer to
Table 2 for the pin configurations and their corresponding
addresses.
Bynowallothernonmatchingslavedeviceswillhavegone
back to their original standby states to wait for the next
Start signal. Meanwhile, upon receiving the acknowledge
from the matching slave, the master then sends out the
command byte (see Table 1).
Table 2. Address Pin Truth Table
AD1
GND
ADDRESS
1011000
1011001
1011010
V
/2
CC
V
CC
Table 1. Switch Control Table
COMMAND
Switch 0
Switch 1
XXXXXX00
SW0 Off
SW1 Off
XXXXXX01
SW0 On
SW1 Off
XXXXXX10
SW0 Off
SW1 On
XXXXXX11
SW0 On
SW1 On
To conserve standby current, it is preferable to tie the
address pins to either VCC or GND. If three LTC1710s are
needed, then the address pin can be tied to the third state
of VCC/2 by using two equal value resistors (≤1M), see
Figure 2.
After receiving the command byte, the slave device
(LTC1710) needs to acknowledge the master again by
pulling the DATA line low on the following clock cycle. The
master then ends this Send Byte Protocol by sending the
Stop signal, which is a transition from low to high on the
DATA line while the CLK line is high. Valid data is shifted
into the output latch on the last acknowledge signal; the
output switch will not turn on, however, until the Stop
signal is detected. This double buffering feature of the
output latch allows the user to “daisy-chain” multiple
SMBus devices such that their outputs are synchronously
5V
6
5
8
1
DATA
CLK
V
CC
SW0D
LOAD 1
LOAD 2
LTC1710
1M
1M
3
4
2
7
AD1
GND
OUT0
OUT1
1710 F02
Figure 2. The LTC1710 Programmed with Address 1011001
EXECUTION OF DATA STORED IN
OUTPUT LATCH OF DEVICES WITH
ADDR1, ADDR2 AND ADDR3
START ADDR1 A COMMAND A START ADDR2 A COMMAND A START ADDR3 A COMMAND A STOP
1710 F01
Figure 1. Daisy-Chain Example
Example of Send Byte Protocol to Slave Address 1011000 Turning SW0 and SW1 On
CLK
START
1
0
1
1
0
0
0
0
ACK
0
0
0
0
0
0
1
1
ACK
STOP
(PROGRAMMABLE)
(WRITE)
(SW1 (SW0
ON) ON)
DATA
1710 TA03
ADDRESS BYTE
COMMAND BYTE
6
LTC1710
U
OPERATIO
Charge Pump
until about 300µs after VCC crosses the undervoltage
lockoutthreshold(typically2V). Thecircuitincludessome
hysteresisanddelaytoavoidnuisanceresets.Onceopera-
tion begins, VCC must drop below the threshold for at least
100µs to trigger another POR sequence.
To fully enhance the internal N-channel power switches,
an internal charge pump is used to boost the gate drive to
amaximumof6VaboveVCC. Thereasonforthemaximum
charge pump output voltage limit is to protect the internal
switches from excessive gate overdrive. A feedback net-
work is used to limit the charge pump output once it is 6V
aboveVCC. Topreventthepowerswitchesfromturningon
too fast, an internal current source is placed between the
output of the charge pump and the gate of the power
switch to control the ramp rate.
Input Threshold
Anticipating the trend of lower and lower supply voltages,
the SMBus is specified with a VIH of 1.4V and a VIL of 0.6V.
WhilesomeSMBuspartsmayviolatethisstringentSMBus
specification by specifying a higher VIH value for a corre-
sponding higher input supply voltage, the LTC1710 meets
and maintains the constant SMBus input threshold speci-
ficationthroughouttheentiresupplyvoltagerangeof2.7V
to 5.5V.
Since the charge pumps are driving just the gates of the
internal switches, only a small amount of current is
required. Therefore, all the charge pump capacitors are
integrated onboard. The drain of switch 1 is internally
connected to VCC, however, the drain of switch 0 is user
controlled through Pin 1. In other words, SMBus devices
using different power supply voltages can be simulta-
neously switched by the same LTC1710.
Thermal Shutdown
In the unlikely event that either power switch overheats, a
thermal shutdown circuit, which is placed closely to the
two switches, will activate and turn off the gate drives to
bothswitches. The thermalshutdowncircuithas athresh-
old of 120°C with a 15°C hysteresis.
Power-On Reset and Undervoltage Lockout
The LTC1710 starts up with both gate drives low. An
internal power-on reset (POR) signal inhibits operation
U
TYPICAL APPLICATIONS
The LTC1710, when used with the LT®1521-3.3, can
switcharegulated3.3V/300mAsupplytoaload(Figure3).
Also, with the help of the LT1304-5, the LTC1710 can be
used to make a boost switching regulator with output
disconnect and a low standby current of 22µA (Figure 5).
5V
3.3V
5V
10µF
10µF
10µF
8
1
SW0D
OUT0
8
V
V
CC
CC
5
2
7
5
7
8
5
1
2
3.3V
3.3V
CLK
CLK
OUT1
V
V
OUT
IN
LOAD
1µF
FROM SMBus
LTC1710
DATA
FROM SMBus
LTC1710
LT1521-3.3
SHDN SENSE
6
3
6
3
DATA
1
2
SW0D
OUT0
5V
LOAD
SWITCHED
3.3V
AD1
OUT1
GND
AD1
1.5µF
GND
1710 F03
PROGRAMMABLE
PROGRAMMABLE
4
4
1710 F04
Figure 3. Low Dropout Regulator Switching a 3.3V/300mA Supply
Figure 4. The LTC1710 Switching Two Different Voltage Loads
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
7
LTC1710
TYPICAL APPLICATIONS
U
3.3V
10µF
8
1
SW0D
OUT0
V
CC
CLK
5
2
7
FROM SMBus
LTC1710
DATA
3.3V
LOAD
6
3
1N5817
22µH*
+
AD1
OUT1
GND
100µF
3
4
SW
PROGRAMMABLE
499k
604k
V
IN
4
8
2
5V
200mA
SENSE
+
LT1304-5
LBI
SHDN GND
100k
LBO
1
2200µF
LBO
7
5
*SUMIDA CD54-220
SHUTDOWN
1710 F05
Figure 5. Switching Regulator with Low-Battery Detect Using 22µA of Standby Current
U
PACKAGE DESCRIPTION
Dimensions in inches (millimeters), unless otherwise noted.
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
MS8 Package
8-Lead Plastic MSOP
(LTC DWG # 05-08-1660)
0.189 – 0.197*
(4.801 – 5.004)
0.118 ± 0.004*
(3.00 ± 0.102)
7
5
8
6
8
7
6
5
0.118 ± 0.004**
(3.00 ± 0.102)
0.192 ± 0.004
(4.88 ± 0.10)
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
1
2
3
4
1
2
3
4
0.040 ± 0.006
(1.02 ± 0.15)
0.034 ± 0.004
(0.86 ± 0.102)
0.010 – 0.020
(0.254 – 0.508)
× 45°
0.053 – 0.069
(1.346 – 1.752)
0.007
(0.18)
0° – 6° TYP
0.004 – 0.010
(0.101 – 0.254)
0.008 – 0.010
(0.203 – 0.254)
SEATING
PLANE
0°– 8° TYP
0.012
(0.30)
REF
0.021 ± 0.006
(0.53 ± 0.015)
0.006 ± 0.004
(0.15 ± 0.102)
MSOP (MS8) 1197
0.0256
(0.65)
TYP
0.016 – 0.050
0.406 – 1.270
0.050
(1.270)
TYP
0.014 – 0.019
(0.355 – 0.483)
*
DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH,
PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
SO8 0996
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC1304
Micropower DC/DC Converter
Low-Battery Detector Active in Shutdown
Current Limit
LTC1470/LTC1471 Single and Dual PCMCIA Protected 3.3V/5V V Switches
CC
LTC1473
LTC1623
Dual PowerPathTM Switch Matrix
Current Limit with Timer
SMBus Dual High Side Switch Controller
Uses External Switches, Two Three-State Address Pins
PowerPath is a trademark of Linear Technology Corporation.
1710f LT/TP 0998 4K • PRINTED IN USA
LINEAR TECHNOLOGY CORPORATION 1998
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
8
●
●
(408)432-1900 FAX:(408)434-0507 www.linear-tech.com
相关型号：
LTC1710CS8#PBF
LTC1710 - SMBus Dual High Side Switch; Package: SO; Pins: 8; Temperature Range: 0°C to 70°C
Linear
LTC1710CS8#TR
LTC1710 - SMBus Dual High Side Switch; Package: SO; Pins: 8; Temperature Range: 0°C to 70°C
Linear
LTC1710CS8#TRPBF
LTC1710 - SMBus Dual High Side Switch; Package: SO; Pins: 8; Temperature Range: 0°C to 70°C
Linear
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