LINER LTC1710C Smbus dual monolithic high side switch Datasheet

LTC1710
SMBus Dual Monolithic
High Side Switch
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FEATURES
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■
■
DESCRIPTION
Two 0.4Ω/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
Built-In Undervoltage Lockout
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APPLICATIONS
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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.
The LTC1710 has one three-state programmable
address pin that allows three different addresses for a total
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.
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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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
5.5V while maintaining the SMBus specified 0.6V VIL and
1.4V VIH input thresholds.
TYPICAL APPLICATION
Switch Voltage Drop
vs Load Current
VCC
2.7V TO 5.5V
SW0D
0V TO VCC
1
10µF
SW0
CLOCK
FROM SMBus
DATA
AD1
(PROGRAMMABLE)
5
6
2
LOAD 1
CHARGE
PUMP
3
7
SW1
SWITCH VOLTAGE DROP (mV)
8
10µF
500
TA = 25°C
400
300
200
VCC = 2.7V
VCC = 3.3V
100
VCC = 5V
LOAD 2
LTC1710
0
4
1710 TA01
0
200
100
300
LOAD CURRENT (mA)
400
1710 TA02
1
LTC1710
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W W
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ABSOLUTE MAXIMUM RATINGS
(Voltages Referred to GND Pin) (Note 1)
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)
Continuous .................................................... 300mA
Pulsed, < 10µs (nonrepetitive) ............................... 1A
Operating Temperature Range
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.
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PACKAGE/ORDER INFORMATION
ORDER PART
NUMBER
TOP VIEW
SW0D
OUT0
AD1
GND
1
2
3
4
8
7
6
5
VCC
OUT1
DATA
CLK
MS8 PACKAGE
8-LEAD PLASTIC MSOP
LTC1710CMS8
MS8 PART MARKING
TJMAX = 110°C, θJA = 150°C/ W
ORDER PART
NUMBER
TOP VIEW
SW0D 1
8
VCC
OUT0 2
7
OUT1
AD1 3
6
DATA
GND 4
5
CLK
LTC1710CS8
LTC1710IS8
S8 PART MARKING
S8 PACKAGE
8-LEAD PLASTIC SO
LTDZ
1710
1710I
TJMAX = 110°C, θJA = 110°C/ W
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
VCC
Operating Supply Voltage Range
IVCC
Supply Current
RDS(ON)
Power Switch On Resistance
TA = 25°C, VCC = SW0D = 5V unless otherwise noted.
CONDITIONS
●
TYP
2.7
MAX
UNITS
5.5
V
Charge Pump Off, AD1 High or Low,
DATA and CLK High
VCC = 5V
VCC = 3.3V
VCC = 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
0.55
0.46
0.40
0.7
0.6
Ω
Ω
Ω
VCC = 2.7V, IOUT = 300mA
VCC = 3.3V, IOUT = 300mA
VCC = 5V, IOUT = 300mA
VUVLO
Undervoltage Lockout
Falling Edge (Note 2)
tPOR
Power-On Reset Delay Time
VCC = 2.7V (Note 3)
VCC = 5.5V
fOSC
Charge Pump Oscillator Frequency
(Note 3)
2
MIN
●
1.5
2.0
2.5
V
300
300
1000
1000
µs
µs
300
kHz
LTC1710
ELECTRICAL CHARACTERISTICS
TA = 25°C, VCC = SW0D = 5V unless otherwise noted.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
tON
Output Turn-On Time
(100Ω/1µF Load)
VCC = 2.7V (From ON (Note 6) to VOUT = 90% VCC)
VCC = 5.5V (From ON (Note 6) to VOUT = 90% VCC)
200
160
µs
µs
tOFF
Output Turn-Off Time
(100Ω/1µF Load)
VCC = 2.7V (From OFF (Note 7) to VOUT = 10% VCC)
VCC = 5.5V (From OFF (Note 7) to VOUT = 10% VCC)
250
250
µs
µs
VIL
DATA/CLK Input Low Voltage
AD1 Input Low Voltage
VCC = 2.7V to 5.5V
VCC = 2.7V to 5.5V
●
●
VIH
DATA/CLK High Voltage
AD1 Input High Voltage
VCC = 2.7V to 5.5V
VCC = 2.7V to 5.5V
●
●
VOL
Data Output Low Voltage
VCC = 2.7V to 5.5V, IPULL-UP = 350µA
●
CIN
Input Capacitance (DATA, CLK, AD1)
IIN
Input Leakage Current (DATA, CLK)
●
±1
µA
Input Leakage Current (AD1)
●
±250
nA
100
kHz
0.6
0.2
V
V
1.4
VCC – 0.2
V
V
0.18
0.4
V
5
pF
SMBus Related Specifications (Note 5)
fSMB
SMBus Operating Frequency
10
tBUF
Bus Free Time Between
Stop and Start
4.7
µs
tSU:STA
Start Condition Setup Time
4.7
µs
tHD:STA
Start Condition Hold Time
4.0
µs
tSU:STO
Stop Condition Setup Time
4.0
µs
tHD: DAT
Data Hold Time
300
ns
tSU:DAT
Data Setup Time
250
ns
tLOW
Clock Low Period
4.7
tHIGH
Clock High Period
4.0
tf
Clock/Data Fall Time
300
ns
tr
Clock/Data Rise Time
1000
ns
IPULL-UP
Current Through External Pull-Up
Resistor on DATA Pin
350
µA
VCC = 2.7V to 5.5V
(Open-Drain Data Pull-Down Current Capacity)
The ● denotes specifications which apply over the full operating
temperature range.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: Approximately 3% hysteresis is provided to ensure stable operation
and eliminate false triggering by minor VCC glitches.
Note 3: Measured from VCC > VUVLO to SMBus ready for DATA input.
100
µs
µs
50
Note 4: The oscillator frequency is not tested directly but is inferred from
turn-on time.
Note 5: SMBus timing specifications are guaranteed but not tested.
Note 6: ON is enabled upon receiving the Stop condition from the SMBus
master.
Note 7: OFF is enabled upon receiving the Stop condition from the SMBus
master.
3
LTC1710
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TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current (IQ)
vs Supply Voltage
Supply Current (IQ)
vs Temperature
Standby Current vs Temperature
50
500
500
TA = 25°C
40
400
30
VCC = 3.3V
VCC = 5V
10
BOTH SW ON
200
SW1 ON
SW0 ON
50
0
TEMPERATURE (°C)
50
0
TEMPERATURE (°C)
IOUT = 300mA
0.6
0.5
400
IPULL-UP = 350µA
0.8
SWITCH RDS(ON) (Ω)
SWITCH RDS(ON) (Ω)
0.8
Data ACK VOL vs Temperature
IOUT = 300mA
0.9
VCC = 2.7V
VCC = 3.3V
VCC = 5V
0.4
0.3
0.4
VCC = 5V
0.3
0.1
100
VCC = 3.3V
0.5
0.1
0
50
TEMPERATURE (°C)
VCC = 2.7V
0.6
0.2
0
– 50
300
0.7
0.2
0
8
1710 G03
Switch RDS(ON) vs Temperature
(MSOP Package)
1.0
0.7
2
4
6
SUPPLY VOLTAGE (V)
0
1710 G02
Switch RDS(ON) vs Temperature
(SO-8 Package)
0.9
SW1 ON
SW0 ON
200
100
1710 G01
1.0
BOTH SW ON
0
0
– 50
100
300
100
100
VCC = 2.7V
0
– 50
300
DATA ACK VOL (mV)
20
SUPPLY CURRENT (µA)
400
SUPPLY CURRENT (µA)
STANDBY CURRENT (µA)
VCC = 5V
200
100
0
20
60
40
TEMPERATURE (°C)
1710 G04
80
100
1710 G05
0
– 50
0
50
TEMPERATURE (°C)
100
1710 G06
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PIN FUNCTIONS
SW0D (Pin 1): Drain Supply of Switch 0. User-programmable from 0V to VCC.
OUT0 (Pin 2): Source Output of Switch 0. Maximum load
of 300mA; controlled by LSB of command byte.
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.
GND (Pin 4): Ground Connection.
CLK (Pin 5): Serial Clock Interface. Must be pulled high to
VCC with external resistor. The pull-up current must be
limited to 350µA.
DATA (Pin 6): Open-Drain Connected Serial Data Interface. Must be pulled high to VCC with external resistor. The
pull-up current must be limited to 350µA.
OUT1 (Pin 7): Source Output of Switch 1. Maximum load
of 300mA; controlled by 2nd LSB of command byte.
VCC (Pin 8): Input Supply Voltage. Operating range from
2.7V to 5.5V.
4
LTC1710
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BLOCK DIAGRA
POWER-ON
RESET
UNDERVOLTAGE
LOCKOUT
VCC 8
VCC
2V
START
AND
STOP
DETECTORS
VCC
ACK
DATA 6
INPUT
BUFFERS
SHIFT
REGISTER
LOGIC
7 OUT1
A
CLK 5
B
OUTPUT
LATCHES
REGULATED
CHARGE
PUMPS
THERMAL
SHUTDOWN
1 SW0D
COUNTER
2 OUT0
ADDRESS
DECODER
AD1 3
GND
ADDRESS
COMPARATOR
4
1710 BD
WU
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TI I G DIAGRA
CLK
tHD:STA
tHIGH
tSU:DAT
tSU:STA
tr
tHD:DAT
tf
tLOW
tSU:STO
DATA
START
STOP
1710 TD
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OPERATIO
SMBus Operation
SMBus is a serial bus interface that uses only two bus lines,
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.
The SMBus specification establishes a set of protocols that
devices on the bus must follow for communications.
The protocol that the LTC1710 uses is the Send Byte Protocol. 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 simultaneously; 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
the bus wake up and prepare to shift in the next byte of data.
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LTC1710
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OPERATIO
The master then sends out the first byte. The first seven
bits of this byte consist of the address of the device that the
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
can only be written to by a master, it will ignore the ensuing
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.
By now all other nonmatching slave devices will have gone
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).
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.
Table 2. Address Pin Truth Table
AD1
GND
VCC /2
VCC
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
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
ADDRESS
1011000
1011001
1011010
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.
5V
6
5
DATA
CLK
VCC
SW0D
8
1
LTC1710
3
4
AD1
OUT0
GND
OUT1
1M
LOAD 1
2
7
LOAD 2
1M
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
(PROGRAMMABLE)
0
(WRITE)
ACK
0
0
0
0
0
0
1
(SW1
ON)
1
(SW0
ON)
ACK
STOP
DATA
ADDRESS BYTE
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COMMAND BYTE
1710 TA03
LTC1710
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OPERATIO
Charge Pump
To fully enhance the internal N-channel power switches,
an internal charge pump is used to boost the gate drive to
a maximum of 6V above VCC. The reason for the maximum
charge pump output voltage limit is to protect the internal
switches from excessive gate overdrive. A feedback network is used to limit the charge pump output once it is 6V
above VCC. To prevent the power switches from turning on
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.
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 simultaneously switched by the same LTC1710.
Power-On Reset and Undervoltage Lockout
The LTC1710 starts up with both gate drives low. An
internal power-on reset (POR) signal inhibits operation
until about 300µs after VCC crosses the undervoltage
lockout threshold (typically 2V). The circuit includes some
hysteresis and delay to avoid nuisance resets. Once operation begins, VCC must drop below the threshold for at least
100µs to trigger another POR sequence.
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.
While some SMBus parts may violate this stringent SMBus
specification by specifying a higher VIH value for a corresponding higher input supply voltage, the LTC1710 meets
and maintains the constant SMBus input threshold specification throughout the entire supply voltage range of 2.7V
to 5.5V.
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
both switches. The thermal shutdown circuit has a threshold of 120°C with a 15°C hysteresis.
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TYPICAL APPLICATIONS
The LTC1710, when used with the LT®1521-3.3, can
switch a regulated 3.3V/300mA supply to a load (Figure 3).
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
5V
10µF
10µF
10µF
8
8
5
FROM SMBus
6
3
PROGRAMMABLE
3.3V
VCC
CLK
OUT1
7
1µF
LTC1710
DATA
SW0D
AD1
OUT0
GND
8
5
1
2
SWITCHED
3.3V
VIN
VOUT
LT1521-3.3
SHDN SENSE
1
5
3.3V
FROM SMBus
2
3
1.5µF
1710 F03
6
VCC
1
SW0D
CLK
OUT0
2
3.3V
LOAD
7
5V
LOAD
LTC1710
DATA
AD1
PROGRAMMABLE
OUT1
GND
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
7
LTC1710
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TYPICAL APPLICATIONS
3.3V
8
5
FROM SMBus
10µF
1
VCC
SW0D
CLK
2
OUT0
LTC1710
6
DATA
3
AD1
+
7
OUT1
100µF
3
4
VIN
SW
GND
PROGRAMMABLE
3.3V
LOAD
1N5817
22µH*
499k
4
SENSE
LT1304-5
1
604k
LBI
SHDN
LBO
GND
7
8
2
5V
200mA
+
100k
2200µF
LBO
5
*SUMIDA CD54-220
SHUTDOWN
1710 F05
Figure 5. Switching Regulator with Low-Battery Detect Using 22µA of Standby Current
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PACKAGE DESCRIPTION
Dimensions in inches (millimeters), unless otherwise noted.
MS8 Package
8-Lead Plastic MSOP
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1660)
(LTC DWG # 05-08-1610)
0.189 – 0.197*
(4.801 – 5.004)
0.118 ± 0.004*
(3.00 ± 0.102)
8
7 6
8
5
0.118 ± 0.004**
(3.00 ± 0.102)
0.192 ± 0.004
(4.88 ± 0.10)
1
2 3
5
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
1
0.034 ± 0.004
(0.86 ± 0.102)
0.010 – 0.020
× 45°
(0.254 – 0.508)
0° – 6° TYP
0.021 ± 0.006
(0.53 ± 0.015)
6
4
0.040 ± 0.006
(1.02 ± 0.15)
0.007
(0.18)
7
SEATING
PLANE 0.012
(0.30)
0.0256
REF
(0.65)
TYP
0.006 ± 0.004
(0.15 ± 0.102)
* 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 INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
0.008 – 0.010
(0.203 – 0.254)
3
4
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0°– 8° TYP
0.016 – 0.050
0.406 – 1.270
MSOP (MS8) 1197
2
0.014 – 0.019
(0.355 – 0.483)
0.050
(1.270)
TYP
*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
SO8 0996
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC1304
Micropower DC/DC Converter
Low-Battery Detector Active in Shutdown
LTC1470/LTC1471 Single and Dual PCMCIA Protected 3.3V/5V VCC Switches
Current Limit
LTC1473
Dual PowerPathTM Switch Matrix
Current Limit with Timer
LTC1623
SMBus Dual High Side Switch Controller
Uses External Switches, Two Three-State Address Pins
PowerPath is a trademark of Linear Technology Corporation.
8
Linear Technology Corporation
1710f LT/TP 0998 4K • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com
 LINEAR TECHNOLOGY CORPORATION 1998
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