Datasheet LTC1710 Datasheet (Linear Technology)

FEATURES

■

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

LTC1710

SMBus Dual Monolithic

High Side Switch

U

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 14µ A (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.
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.

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APPLICATIONS

■

Handheld Computer Power Management

■

Computer Peripheral Control

■

Laptop Computer Power Plane Switching

■

Portable Equipment Power Control

■

Industrial Control Systems

■

ACPI SMBus Interface

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TYPICAL APPLICATION

V

CC

2.7V TO 5.5V

81

SW0

5

CLOCK

FROM SMBus

(PROGRAMMABLE)

DATA

AD1

CHARGE

6

PUMP

3

SW1

LTC1710

SW0D
0V TO V

4

CC

2

7

10µF10µF

LOAD 1

LOAD 2

1710 TA01

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.

, LTC and LT are registered trademarks of Linear Technology Corporation.

Switch Voltage Drop

vs Load Current

500

T

= 25°C

A

400

300

200

100

SWITCH VOLTAGE DROP (mV)

0

100

0

LOAD CURRENT (mA)

200

VCC = 2.7V

V

CC

= 5V

V

CC

300

= 3.3V

400

1710 TA02

1

LTC1710

WW

W

U

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, <10µ s (nonrepetitive) ............................... 1A

U

W

U

PACKAGE/ORDER INFORMATION

ORDER PART

TOP VIEW

SW0D

1

OUT0

2

AD1

3

GND

4

MS8 PACKAGE

8-LEAD PLASTIC MSOP

T

= 110°C, θJA = 150°C/W

JMAX

8
7
6
5

V

CC

OUT1
DATA
CLK



NUMBER

LTC1710CMS8

MS8 PART MARKING

LTDZ

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 T

circuitry is set to shut down the switches at T

TOP VIEW

SW0D

1

OUT0

2

AD1

3

GND

4

= 125°C without damage, its internal protection

JMAX

= 120°C with 15°C hysteresis.

J

ORDER PART

NUMBER

V

8

CC

OUT1

7

DATA

6

CLK

5

LTC1710CS8
LTC1710IS8

S8 PART MARKING

S8 PACKAGE

8-LEAD PLASTIC SO

T

= 110°C, θJA = 110°C/W

JMAX

1710
1710I

Consult factory for Military grade parts.

ELECTRICAL CHARACTERISTICS

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

V

CC

I

VCC

R

DS(ON)

V

UVLO

t

POR

f

OSC

Operating Supply Voltage Range ● 2.7 5.5 V
Supply Current Charge Pump Off, AD1 High or Low,

DATA and CLK High
V

CC

V

CC

V

CC

OUT0 or OUT1 High
(Command Byte XXXXXX01 or XXXXXX10) ● 200 300 µA
Both Outputs High (Command Byte XXXXXX11)

Power Switch On Resistance VCC = 2.7V, I

= 3.3V, I

V

CC

= 5V, I

V

CC

Undervoltage Lockout Falling Edge (Note 2) ● 1.5 2.0 2.5 V
Power-On Reset Delay Time VCC = 2.7V (Note 3) 300 1000 µs

= 5.5V 300 1000 µs

V

CC

Charge Pump Oscillator Frequency 300 kHz
(Note 3)

TA = 25°C, VCC = SW0D = 5V unless otherwise noted.

= 5V ● 17 30 µA
= 3.3V ● 14 30 µA
= 2.7V ● 11 30 µA

● 250 500 µA

= 300mA 0.55 Ω

OUT

= 300mA 0.46 0.7 Ω

OUT

= 300mA 0.40 0.6 Ω

OUT

2

LTC1710

ELECTRICAL CHARACTERISTICS

TA = 25°C, VCC = SW0D = 5V unless otherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS

t

t

V

V

V
C
I

ON

OFF

IL

IH

OL

IN

IN

Output Turn-On Time VCC = 2.7V (From ON (Note 6) to V
(100Ω/1µF Load) V

= 5.5V (From ON (Note 6) to V

CC

Output Turn-Off Time VCC = 2.7V (From OFF (Note 7) to V
(100Ω/1µF Load) V

= 5.5V (From OFF (Note 7) to V

CC

= 90% VCC) 200 µs

OUT

= 90% VCC) 160 µs

OUT

= 10% VCC) 250 µs

OUT

= 10% VCC) 250 µs

OUT

DATA/CLK Input Low Voltage VCC = 2.7V to 5.5V ● 0.6 V
AD1 Input Low Voltage V

= 2.7V to 5.5V ● 0.2 V

CC

DATA/CLK High Voltage VCC = 2.7V to 5.5V ● 1.4 V
AD1 Input High Voltage V

Data Output Low Voltage VCC = 2.7V to 5.5V, I

= 2.7V to 5.5V ● VCC – 0.2 V

CC

= 350µA ● 0.18 0.4 V

PULL-UP

Input Capacitance (DATA, CLK, AD1) 5 pF
Input Leakage Current (DATA, CLK) ● ±1 µA
Input Leakage Current (AD1) ● ±250 nA

SMBus Related Specifications (Note 5)

f

SMB

t

BUF

SMBus Operating Frequency 10 100 kHz
Bus Free Time Between 4.7 µs

Stop and Start

t

SU:STA

t

HD:STA

t

SU:STO

t

HD: DAT

t

SU:DAT

t

LOW

t

HIGH

t

f

t

r

I

PULL-UP

Start Condition Setup Time 4.7 µs
Start Condition Hold Time 4.0 µs
Stop Condition Setup Time 4.0 µs
Data Hold Time 300 ns
Data Setup Time 250 ns
Clock Low Period 4.7 µs
Clock High Period 4.0 50 µs
Clock/Data Fall Time 300 ns
Clock/Data Rise Time 1000 ns
Current Through External Pull-Up VCC = 2.7V to 5.5V 100 350 µA

Resistor on DATA Pin (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 V

Note 3: Measured from V

CC

> V

UVLO

glitches.

CC

to SMBus ready for DATA input.

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

SUPPLY VOLTAGE (V)

0

0

SUPPLY CURRENT (µA)

100

200

300

400

500

24

1710 G03

68

BOTH SW ON

SW1 ON

T

A

= 25°C

SW0 ON

TEMPERATURE (°C)

DATA ACK V

OL

(mV)

200

300

100

1710 G06

100

0

–50

0

50

400

I

PULL-UP

= 350µA

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Standby Current vs Temperature

50

40

30

VCC = 3.3V

STANDBY CURRENT (µA)

20

10

0

–50

Switch R

VCC = 5V

V

= 2.7V

CC

0

TEMPERATURE (°C)

vs Temperature

DS(ON)

(SO-8 Package)

1.0
I

= 300mA

OUT

0.9

0.8

0.7

(Ω)

0.6

DS(ON)

0.5

0.4

0.3

SWITCH R

0.2

0.1

0

–50

VCC = 3.3V

050

TEMPERATURE (°C)

50

VCC = 2.7V

V

Supply Current (IQ)
vs Temperature

500

= 5V

V

CC

400

1710 G01

100

300

200

SUPPLY CURRENT (µA)

100

0

–50

Switch R

BOTH SW ON

SW1 ON

0

TEMPERATURE (°C)

vs Temperature

DS(ON)

SW0 ON

50

100

1710 G02

(MSOP Package)

1.0
I

= 300mA

OUT

0.9

0.8

0.7

(Ω)

0.6

DS(ON)

0.5

= 5V

CC

100

1710 G04

0.4

0.3

SWITCH R

0.2

0.1

0

0

V

= 3.3V

CC

20

40

TEMPERATURE (°C)

60

VCC = 2.7V

= 5V

V

CC

80

100

1710 G05

Supply Current (IQ)
vs Supply Voltage

Data ACK VOL vs Temperature

UUU

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.

4

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.

BLOCK DIAGRA

LTC1710

W

V

DATA

CLK

AD1

CHARGE

PUMPS

POWER-ON

RESET

THERMAL

SHUTDOWN

V

CC

7

OUT1

12SW0D

OUT0

GND

4

1710 BD

UNDERVOLTAGE

LOCKOUT

8

CC

V

CC

START

AND

STOP

DETECTORS

6

INPUT

BUFFERS

5

3

SHIFT

REGISTER

COUNTER

ADDRESS
DECODER

ADDRESS

COMPARATOR

LOGIC

ACK

A

B

2V

OUTPUT

LATCHES

REGULATED

UW W

TI I G DIAGRA

CLK

t

DATA

t

SU:DAT

HIGH

t

t

SU:STA

START STOP

HD:STA

t

t

HD:DAT

r

U

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.

t

f

t

LOW

t

SU:STO

1710 TD

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.

5

LTC1710

5

3

6

4

1

2

1M

5V

8

7

1710 F02

DATA
CLK

AD1

SW0D

OUT0

V

CC

LTC1710

OUT1

GND

LOAD 1

LOAD 2

1M

OPERATIO

U

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).

Table 1. Switch Control Table

COMMAND XXXXXX00 XXXXXX01 XXXXXX10 XXXXXX11

Switch 0 SW0 Off SW0 On SW0 Off SW0 On
Switch 1 SW1 Off SW1 Off SW1 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

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 ADDRESS

GND 1011000

VCC/2 1011001

V

CC

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.

Figure 2. The LTC1710 Programmed with Address 1011001

6

EXECUTION OF DATA STORED IN

START ADDR1 ADDR2COMMAND COMMANDA START STARTA A A A AADDR3 COMMAND

STOP

1710 F01

OUTPUT LATCH OF DEVICES WITH
ADDR1, ADDR2 AND ADDR3

Figure 1. Daisy-Chain Example

Example of Send Byte Protocol to Slave Address 1011000 Turning SW0 and SW1 On

CLK

DATA

(PROGRAMMABLE)

ADDRESS BYTE COMMAND BYTE

(WRITE)

ACK0

1

000000001101START 0

(SW1

ON)

1

(SW0

ON)

ACK

STOP

1710 TA03

OPERATIO

LTC1710

U

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
100µ s 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.

U

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

5V

10µF

8

V

CC

5

CLK

FROM SMBus

PROGRAMMABLE

LTC1710

6

DATA

3

AD1

GND

Figure 3. Low Dropout Regulator Switching a 3.3V/300mA Supply

OUT1

SW0D

OUT0

4

7

1
2

8

V

IN

1µF

LT1521-3.3

5

SHDN

SWITCHED

3.3V

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.

V

OUT

SENSE

1

3.3V

2

1.5µF

1710 F03

used to make a boost switching regulator with output
disconnect and a low standby current of 22µ A (Figure 5).

5V

3.3V

10µF10µF

81

FROM SMBus

PROGRAMMABLE

VCCSW0D

5

CLK

6

DATA

3

AD1

LTC1710

GND

OUT0

OUT1

4

2

7

3.3V

LOAD

5V

LOAD

1710 F04

Figure 4. The LTC1710 Switching Two Different Voltage Loads

7

LTC1710

1

2

3

4

0.150 – 0.157**
(3.810 – 3.988)

8

7

6

5

0.189 – 0.197*
(4.801 – 5.004)

0.228 – 0.244

(5.791 – 6.197)

0.016 – 0.050

0.406 – 1.270

0.010 – 0.020

(0.254 – 0.508)

× 45°

0°– 8° TYP

0.008 – 0.010

(0.203 – 0.254)

SO8 0996

0.053 – 0.069

(1.346 – 1.752)

0.014 – 0.019

(0.355 – 0.483)

0.004 – 0.010

(0.101 – 0.254)

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



*



**

U

TYPICAL APPLICATIONS

3.3V

5

FROM SMBus

PROGRAMMABLE

CLK

6

DATA

3

AD1

Figure 5. Switching Regulator with Low-Battery Detect Using 22µA of Standby Current

PACKAGE DESCRIPTION

MS8 Package

8-Lead Plastic MSOP

(LTC DWG # 05-08-1660)

0.118 ± 0.004*
(3.00 ± 0.102)

2

7

10µF

+

100µF

499k

604k

34

VINSW

LT1304-5

LBI
SHDN

SHUTDOWN

22µH*

SENSE

LBO

GND

57

1N5817

8

100k

21

LBO

*SUMIDA CD54-220

+

81

VCCSW0D

OUT0

LTC1710

OUT1

GND

4

U

Dimensions in inches (millimeters), unless otherwise noted.

S8 Package

8-Lead Plastic Small Outline (Narrow 0.150)

(LTC DWG # 05-08-1610)

8

7

6

5

5V
200mA

2200µF

LOAD

1710 F05

3.3V

0.007
(0.18)

0.021 ± 0.006

(0.53 ± 0.015)

 *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

RELATED PARTS

0° – 6° TYP

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

1630 McCarthy Blvd., Milpitas, CA 95035-7417

[phone] ● FAX: [phone]

SEATING

PLANE

0.192 ± 0.004

(4.88 ± 0.10)

0.040 ± 0.006
(1.02 ± 0.15)

0.012

(0.30)

REF

4

12

3

0.0256
(0.65)



TYP

●

www.linear-tech.com

0.118 ± 0.004**
(3.00 ± 0.102)

0.034 ± 0.004

(0.86 ± 0.102)

0.006 ± 0.004
(0.15 ± 0.102)

MSOP (MS8) 1197

1710f LT/TP 0998 4K • PRINTED IN USA

 LINEAR TECHNOLOGY CORPORATION 1998