Datasheet LTC1155 Datasheet (LINEAR TECHNOLOGY)

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LTC1155

Dual High Side

Micropower MOSFET Driver

EATU

■

Fully Enhances N-Channel Power MOSFETs

■

8µA Standby Current

■

85µA ON Current

■

Short-Circuit Protection

■

Wide Power Supply Range: 4.5V to 18V

■

Controlled Switching ON and OFF Times

■

No External Charge Pump Components

■

Replaces P-Channel High Side MOSFETs

■

Compatible with Standard Logic Families

■

Available in 8-Pin SO Package

PPLICATI

■

Laptop Power Bus Switching

■

SCSI Termination Power Switching

■

Cellular Phone Power Management

■

P-Channel Switch Replacement

■

Relay and Solenoid Drivers

■

Low Frequency Half H-Bridge

■

Motor Speed and Torque Control

U S

DUESCRIPTIO

The LTC®1155 dual high side gate driver allows using low cost N-channel FETs for high side switching applications. An internal charge pump boosts the gate above the positive rail, fully enhancing an N-channel MOSFET with no external components. Micropower operation, with 8µA standby current and 85µA operating current, allows use in virtually all systems with maximum efficiency.

Included on-chip is overcurrent sensing to provide automatic shutdown in case of short circuits. A time delay can be added in series with the current sense to prevent false triggering on high in-rush loads such as capacitors and incandescent lamps.

The LTC1155 operates off of a 4.5V to 18V supply input and safely drives the gates of virtually all FETs. The LTC1155 is well suited for low voltage (battery-powered) applications, particularly where micropower “sleep” operation is required.

The LTC1155 is available in both 8-pin PDIP and 8-pin SO packages.

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

PPLICATITYPICAL

Laptop Computer Power Bus Switch with Short Circuit Protection

VS = 4.5V TO 5.5V

DS2V

IN2

*SURFACE MOUNT

10µF

TTL, CMOS INPUT

DISK

DRIVE

DISPLAY

MAX

5A



SEN

0.02Ω



DLY

100k

*IRLR034

TTL, CMOS INPUT

POWER BUS

SYSTEM



DLY

0.1µF

DS1

LTC1155

IN1

GND

µP

GND



DLY

0.1µF

DLY

100k

*IRLR034



PRINTER,

ETC.

SEN

0.02Ω

5A MAX



1155 TA01

Switch Voltage Drop

0.25

0.20

0.15

0.10

VOLTAGE DROP (V)

0.05

0.00 0

123

OUTPUT CURRENT (A)

1155 TA02

LTC1155

LUTEXI T

WUW

ARB

U G

(Note 1)

Supply Voltage ........................................................ 22V

Input Voltage ...................... (VS +0.3V) to (GND – 0.3V)

Gate Voltage .........................(VS +24V) to (GND – 0.3V)

Current (Any Pin).................................................. 50mA

Storage Temperature Range ................. – 65°C to 150°C

PACKAGE

1

DS1

2

G1

3

GND

IN1

J8 PACKAGE

8-LEAD CERDIP

= 150°C, θJA = 100°C/W (J8)

JMAX

= 100°C, θJA = 130°C/W (N8)

JMAX

TOP VIEW

N8 PACKAGE 8-LEAD PDIP

RDER I FOR ATIO

ORDER PART

8

DS2

7

G2



6

IN2

5



NUMBER

LTC1155CN8 LTC1155CJ8 LTC1155IN8 LTC1155MJ8

Operating Temperature Range

LTC1155C................................................ 0°C to 70°C

LTC1155I........................................... –40°C to 85°C

LTC1155M........................................ – 55°C to 125°C

Lead Temperature Range (Soldering, 10 sec.)...... 300°C

ORDER PART

NUMBER

LTC1155CS8 LTC1155IS8

S8 PART MARKING

1155 1155I

DS1

1

G1

2

GND

3

IN1

S8 PACKAGE

8-LEAD PLASTIC SO

= 100°C, θJA = 150°C/W

JMAX

TOP VIEW

DS2

8

G2

7



6

IN2

LECTRICAL C CHARA TERIST

ICS

The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = 4.5V to 18V, unless otherwise noted.

LTC1155M LTC1155C/LTC1155I

SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS

INH

INL

SEN

GATE-VS

Supply Voltage ● 4.5 18 4.5 18 V Quiescent Current OFF VIN = 0V, VS = 5V (Note 2) 8 20 8 20 µA Quiescent Current ON VS = 5V, VIN = 5V (Note 3) 85 120 85 120 µA Quiescent Current ON VS = 12V, VIN = 5V (Note 3) 180 400 180 400 µA Input High Voltage ● 2.0 2.0 V Input Low Voltage ● 0.8 0.8 V Input Current 0V < VIN < V Input Capacitance 5 5 pF Drain Sense Threshold Voltage 80 100 120 80 100 120 mV

Drain Sense Input Current 0V < V Gate Voltage Above Supply VS = 5V ● 6.0 6.8 9.0 6.0 6.8 9.0 V

= 6V ● 7.5 8.5 15 7.5 8.5 15 V

VS = 12V ● 15 18 25 15 18 25 V

Turn ON Time VS = 5V, C

Time for V Time for V

VS = 12V, C Time for V Time for V

SEN

< V

= 1000pF

GATE

> VS + 2V 50 250 750 50 250 750 µs

GATE

> VS + 5V 200 1100 2000 200 1100 2000 µs

GATE

= 1000pF

GATE

> VS + 5V 50 180 500 50 180 500 µs

GATE

> VS + 10V 120 450 1200 120 450 1200 µs

GATE

● ±1.0 ±1.0 µA

● 75 100 125 75 100 125 mV

±0.1 ±0.1 µA

LTC1155

SUPPLY VOLTAGE (V)

V – V (V)

510 20

1155 TPC03

GATE

SUPPLY VOLTAGE (V)

GATE

(V)

24 10

1155 G06

LECTRICAL C CHARA TERIST

The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VS = 4.5V to 18V, unless otherwise noted.

SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS

OFF

Turn OFF Time VS = 5V, C

Short-Circuit Turn OFF Time VS = 5V, C

ICS

Time for V VS = 12V, C

Time for V

Time for V VS = 12V, C

Time for V

LTC1155M LTC1155C/LTC1155I

= 1000pF

GATE

< 1V 10 36 60 10 36 60 µs

GATE

= 1000pF

GATE

< 1V 10 26 60 10 26 60 µs

GATE

= 1000pF

GATE

< 1V 5 16 30 5 16 30 µs

GATE

= 1000pF

GATE

< 1V 5 16 30 5 16 30 µs

GATE

Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired.

Note 2: Quiescent current OFF is for both channels in OFF condition. Note 3: Quiescent current ON is per driver and is measured independently.

LPER

ATYPICA

Standby Supply Current Supply Current/Side (ON) High Side Gate Voltage

= V

= 0V

IN1

IN2

= 25°C

510 20

SUPPLY VOLTAGE (V)

1155 G01

45 40 35

25 20 15

SUPPLY CURRENT ( A)

5 0

Input Threshold Voltage Drain Sense Threshold Voltage Low Side Gate Voltage

2.4

2.2

2.0

1.8

1.6

1.4

1.2

1.0

0.8

INPUT THRESHOLD VOLTAGE (V)

0.6

0.4 0

OFF

1155 G04

510 20

SUPPLY VOLTAGE (V)

CCHARA TERIST

1000

OR V

IN1

900

= 25°C

800 700

600

500 400 300

SUPPLY CURRENT ( A)

200 100

150 140 130 120 110

100

90 80 70 60

DRAIN SENSE THRESHOLD VOLTAGE (V)

510 20

ICS

= 2V

IN2

SUPPLY VOLTAGE (V)

1155 G02

1155 G05

LTC1155

SUPPLY VOLTAGE (V)

TURN-OFF TIME (µs)

510 20

1155 G09

SEN

= VS –1V

NO EXTERNAL DELAY

GATE

= 1000pF

TIME FOR V

GATE

< 1V

PICA

1000

900 800 700 600

500 400

TURN-ON TIME (µs)

300 200 100

50 45

40 35

30 25 20 15

SUPPLY CURRENT (µA)

5 0

–50

LPER

CCHARA TERIST

ICS

Turn ON Time Turn OFF Time Short-Circuit Turn OFF Delay Time

= 1000pF

GATE

VGS = 5V

= 2V

510 20

SUPPLY VOLTAGE (V)

1155 G07

= 100pF

GATE

TIME FOR V

40 35

25 20

TURN OFF TIME ( s)

15 10

5 0

< 1V

GATE

510 20

SUPPLY VOLTAGE (V)

1155 G08

Standby Supply Current Supply Current Per Side (ON) Input ON Threshold

2.4

2.2

2.0

1.8

1.6

1.4

1.2

1.0

INPUT THRESHOLD (V)

0.8

0.6

0.4 –50

–25 0 25 50

TEMPERATURE (°C)

VS = 5V

VS = 18V

VS = 5V

–25 0 25 50

TEMPERATURE (°C)

75 100 125

1155 G10

1000

900

800 700

600 500 400 300

SUPPLY CURRENT (µA)

200 100

VS = 5V

–50

–25 0 25 50

VS = 12V

75 100 125

TEMPERATURE (°C)

1155 G11

75 100 125

1155 G12

UUU

PIN FUNCTIONS

Input Pin

The LTC1155 logic input is a high impedance CMOS gate and should be grounded when not in use. These input pins have ESD protection diodes to ground and supply and, therefore, should not be forced beyond the power supply rails.

Gate Drive Pin

The gate drive pin is either driven to ground when the switch is turned OFF or driven above the supply rail when the switch is turned ON. This pin is a relatively high impedance when driven above the rail (the equivalent of a

few hundred kΩ). Care should be taken to minimize any loading of this pin by parasitic resistance to ground or supply.

Supply Pin

The supply pin of the LTC1155 serves two vital purposes. The first is obvious: it powers the input, gate drive, regulation and protection circuitry. The second purpose is less obvious: it provides a Kelvin connection to the top of the two drain sense resistors for the internal 100mV reference. The supply pin should be connected directly to the power supply source as close as possible to the top of the two sense resistors.

UUU

PIN FUNCTIONS

LTC1155

The supply pin of the LTC1155 should not be forced below ground as this may result in permanent damage to the device. A 300Ω resistor should be inserted in series with the ground pin if negative supply voltages are anticipated.

Drain Sense Pin

As noted previously, the drain sense pin is compared against the supply pin voltage. If the voltage at this pin is more than 100mV below the supply pin, the input latch will be reset and the MOSFET gate will be quickly discharged. Cycle the input to reset the short-circuit latch and turn the MOSFET back on.

BLOCK

IDAGRA

LOW STANDBY

CURRENT

REGULATOR

ANALOG SECTION

100mV

REFERENCE

COMP

10µs

DELAY

This pin is also a high impedance CMOS gate with ESD protection and, therefore, should not be forced beyond the power supply rails. To defeat the over current protection, short the drain sense to supply.

Some loads, such as large supply capacitors, lamps or motors require high inrush currents. An RC time delay must be added between the sense resistor and the drain sense pin to ensure that the drain sense circuitry does not false trigger during start-up. This time constant can be set from a few microseconds to many seconds. However, very long delays may put the MOSFET in risk of being destroyed by a short-circuit condition (see Applications Information section).

DRAIN SENSE

ANALOG DIGITAL

TTL-TO-CMOS

CONVERTER

GND

VOLTAGE

REGULATORS

ONE

SHOT

OPERATIO

The LTC1155 contains two independent power MOSFET gate drivers and protection circuits (refer to the Block Diagram for details). Each half of the LTC1155 consists of the following functional blocks:

TTL and CMOS Compatible Inputs

Each driver input has been designed to accommodate a wide range of logic families. The input threshold is set at

1.3V with approximately 100mV of hysteresis. A voltage regulator with low standby current provides

continuous bias for the TTL to CMOS converters. The TTL

GATE CHARGE AND DISCHARGE CONTROL LOGIC

INPUT LATCH

OSCILLATOR

AND CHARGE

PUMP

GATE CHARGE

GATE

FAST/SLOW

LOGIC

1155 BD

to CMOS converter output enables the rest of the circuitry. In this way the power consumption is kept to a minimum in the standby mode.

Internal Voltage Regulation

The output of the TTL to CMOS converter drives two regulated supplies which power the low voltage CMOS logic and analog blocks. The regulator outputs are isolated from each other so that the noise generated by the charge pump logic is not coupled into the 100mV reference or the analog comparator.

LTC1155

OPERATIO

Gate Charge Pump

Gate drive for the power MOSFET is produced by an adaptive charge pump circuit that generates a gate voltage substantially higher than the power supply voltage. The charge pump capacitors are included on-chip and, therefore, no external components are required to generate the gate drive.

Drain Current Sense

The LTC1155 is configured to sense the drain current of the power MOSFET in high side applications. An internal 100mV reference is compared to the drop across a sense resistor (typically 0.002Ω to 0.1Ω) in series with the drain

PPLICATI

I FOR ATIO

Protecting the MOSFET

The MOSFET is protected against destruction by removing drive from the gate as soon as an overcurrent condition is detected. Resistive and inductive loads can be protected with no external time delay. Large capacitive or lamp loads, however, require that the overcurrent shutdown function be delayed long enough to start the load but short enough to ensure the safety of the MOSFET.

lead. If the drop across this resistor exceeds the internal 100mV threshold, the input latch is reset and the gate is quickly discharged by a large N-channel transistor.

Controlled Gate Rise and Fall Times

When the input is switched ON and OFF, the gate is charged by the internal charge pump and discharged in a controlled manner. The charge and discharge rates have been set to minimize RFI and EMI emissions in normal operation. If a short circuit or current overload condition is encountered, the gate is discharged very quickly (typically a few microseconds) by a large N-channel transistor.

VS = 5.0V

SEN

0.03Ω

IRLZ34



IN1

LTC1155

GND

DS1

DLY

0.22µF



DLY

270k



Example Calculations

Consider the circuit of Figure 1. A power MOSFET is driven by one side of an LTC1155 to switch a high inrush current load. The drain sense resistor is selected to limit the maximum DC current to 3.3A.

= V

SEN

SEN/ITRIP

= 0.1/3.3A = 0.03Ω

A time delay is introduced between R

and the drain

SEN

sense pin of the LTC1155 which provides sufficient delay to start a high inrush load such as large supply capacitors.

In this example circuit, we have selected the IRLZ34 because of its low R

(0.05Ω with VGS = 5V). The FET

DS(ON )

LOAD

GND

1155 F01

Figure 1. Adding an RC Delay

drops 0.1V at 2A and, therefore, dissipates 200mW in normal operation (no heat sinking required).

If the output is shorted to ground, the current through the FET rises rapidly and is limited by the R

DS(ON)

of the FET, the drain sense resistor and the series resistance between the power supply and the FET. Series resistance in the power supply can be substantial and attributed to many sources including harness wiring, PCB traces, supply capacitor ESR, transformer resistance or battery resistance.

LTC1155

MOSFET CURRENT (1 = SET CURRENT)

0.01

OVERCURRENT SHUTDOWN TIME (1= RC)

0.1

5 10 20 100

1155 F02

250

PPLICATI

I FOR ATIO

For this example, we assume a worst-case scenario; i.e., that the power supply to the power MOSFET is “hard” and provides a constant 5V regardless of the current. In this case, the current is limited by the R

of the MOSFET

DS(ON)

and the drain sense resistance. Therefore:

PEAK

= V

SUPPLY

/0.08Ω

= 62.5A

The drop across the drain sense resistor under these conditions is much larger than 100mV and is equal to the drain current times the sense resistance:

DROP

= (I

PEAK

)(R

SEN

)

= 1.88V

By consulting the power MOSFET data sheet SOA graph, we note that the IRLZ34 is capable of delivering 62.5A at a drain-to-source voltage of 3.12V for approximately 10ms.

Graphical Approach to Selecting R

DLY

and C

DLY

Figure 2 is a graph of normalized overcurrent shutdown time versus normalized MOSFET current. This graph can be used instead of the above equation to calculate the RC time constant. The Y axis of the graph is normalized to one RC time constant. The X axis is normalized to the set current. (The set current is defined as the current required to develop 100mV across the drain sense resistor).

An RC time constant can now be calculated which satisfies this requirement:

= =

 







 



–. /–.

0 01 0 054

182

–

−

SEN

•

SEN MAX

–.

001

010

•

0 030 62 5

  



 





This time constant should be viewed as a maximum safe delay time and should be reduced if the competing requirement of starting a high inrush current load is less stringent; i.e., if the inrush time period is calculated at 20ms, the RC time constant should be set at roughly two or three times this time period and not at the maximum of 182ms. A 60ms time constant would be produced with a 270k resistor and a 0.22µF capacitor (as shown in Figure 1).

Figure 2. Shutdown Time vs MOSFET Current

Note that the shutdown time is shorter for increasing levels of MOSFET current. This ensures that the total energy dissipated by the MOSFET is always within the bounds established by the MOSFET manufacturer for safe operation.

In the example presented above, we established that the power MOSFET should not be allowed to pass 62.5A for more than 10ms. 62.5A is roughly 18 times the set current of 3.3A. By drawing a line up from 18 and reflecting it off the curve, we establish that the RC time constant should be set at 10ms divided by 0.054, or 180ms. Both methods result in the same conclusion.

Using a Speed Up Diode

A way to further reduce the amount of time that the power MOSFET is in a short-circuit condition is to “bypass”the delay resistor with a small signal diode as shown in Figure

3. The diode will engage when the drop across the drain sense resistor exceeds 0.7V, providing a direct path to the

LTC1155

PPLICATI

I FOR ATIO

VS = 5.0V

DS1

IN1

LTC1155

GND

Figure 3. Using a Speed-Up Diode

GND



DLY

0.22µF

R 270k

1N4148

DLY

D1

0.025Ω



IRLZ34

LOAD

1155 F03



SEN

sense pin and dramatically reducing the amount of time the MOSFET is in an overload condition. The drain sense resistor value is selected to limit the maximum DC current to 4A. Above 28A, the delay time drops to 10µs.

Switched Supply Applications

If the MOSFET is turned ON and the power supply (battery) removed, the inductor current is delivered by the supply capacitor. The supply capacitor must be large enough to deliver the energy demanded by the discharging inductor.

If the storage capacitor is too small, the supply lead of the LTC1155 may be pulled below ground, permanently destroying the device.

Consider the case of a load inductance of 1mH which is supporting 3A when the 6V power supply connection is interrupted. A supply capacitor of at least 250µF is required to prevent the supply lead of the LTC1155 from being pulled below ground (along with any other circuitry tied to the supply).

Any wire between the power MOSFET source and the load will add a small amount of parasitic inductance in series with the load (approximately 0.4µH/foot). Bypass the power supply lead of the LTC1155 with a minimum of 10µF to ensure that this parasitic load inductance is discharged safely, even if the load is otherwise resistive.

Large inductive loads, such as solenoids, relays and motors store energy which must be directed back to either the power supply or to ground when the supply voltage is interrupted (see Figure 4). In normal operation, when the switch is turned OFF, the energy stored in the inductor is harmlessly absorbed by the MOSFET; i.e., the current flows out of the supply through the MOSFET until the inductor current falls to zero.

IN1

DS1

LTC1155

GND

Figure 4. Switched Supply

GND

DLY

SEN

0.025Ω

IRLZ34

LOAD

1155 F04



Large Inductive Loads

Large inductive loads (>0.1mH) may require diodes connected directly across the inductor to safely divert the stored energy to ground. Many inductive loads have these diodes included. If not, a diode of the proper current rating should be connected across the load to safely divert the stored energy.

Reverse-Battery Protection

The LTC1155 can be protected against reverse-battery conditions by connecting a resistor in series with the ground lead as shown in Figure 5. The resistor limits the supply current to less than 50mA with –12V applied. Since the LTC1155 draws very little current while in normal operation, the drop across the ground resistor is minimal.

The TTL or CMOS driving logic is protected against reverse-battery conditions by the 100k input current limiting resistor. The addition of 100k resistance in series with the input pin will not affect the turn ON and turn OFF times which are dominated by the controlled gate charge and discharge periods.

LTC1155

PPLICATI

100k

IN1

GND

LTC1155

GND

I FOR ATIO

VS = 4.5V TO 18V

DLY

DS1

300Ω 1/4W

DLY

10µF 25V

LOAD

SEN

1155 F05

Figure 5. Reverse Battery Protection

Overvoltage Protection

The MOSFET and load can be protected against overvoltage conditions by using the circuit of Figure 6. The drain sense function is used to detect an overvoltage condition and quickly discharge the power MOSFET gate. The 18V zener diode conducts when the supply voltage exceeds

18.6V and pulls the drain sense pin 0.6V below the supply pin voltage.

The supply voltage is limited to 18.6V and the gate drive is immediately removed from the MOSFET to ensure that it cannot conduct during the overvoltage period. The gate of the MOSFET will be latched OFF until the supply transient is removed and the input turned OFF and ON again.

VS = 4.5V TO 18V

510Ω

IN1

LTC1155

GND

Figure 6. Overvoltage Shutdown and Protection

10k 1N4148

DS1

18V

LOAD

1155 F06

PPLICATITYPICAL

LMC555

ALL COMPONENTS SHOWN ARE SURFACE MOUNT

10µF

= 1Hz

750k

Dual 2A Autoreset Electronic Fuse

100k

0.1µF

30k

IN1

DS1

LTC1155

GND

0.03Ω

1/2 SI9956DY

1N4148

OUT 1 OUT 2

1.0µF

0.1µF

30k

DS2V

IN2

0.03Ω

1/2 SI9956DY

100k

1155 TA03

LTC1155

PPLICATITYPICAL

X-NOR Fault DetectionHigh Side Driver with VDS Sense Short-Circuit Shutdown

4.5V TO 6V

10µF

*ANY 74C OR 74HC LOGIC GATE. MOSFET SHUTS DOWN IF V

IN1

0.01µF

1/2

LTC1155

GND

4.5V TO 6V

30k

DS1

270k

> 1V

IRLZ24

LOAD

1155 TA04

10µF

IN1

1/2

LTC1155

GND

DS1

74C266

100k

FAULT

0.1Ω

10k

IRLD024

LOAD

1155 TA05

Truth Table

IN OUT CONDITION FLT

0 0 Switch OFF 1 1 0 Short Circuit 0 0 1 Open Load 0 1 1 Switch ON 1

Low Side Driver with Drain End Current Sensing Low Side Driver with Source End Current Sensing

IN1

1/2

LTC1155

GND

DS1

51Ω

< 60µA)

51Ω

LT®1077*

10µF

IN1

1/2

LTC1155

GND

DS1

0.05Ω 5%

LOAD

SMP25N05

1155 TA06

10µF

*DO NOT SUBSTITUTE. MUST BE A PRECISION, SINGLE SUPPLY, MICROPOWER OP AMP (I

LOAD

–

SMP25N05

0.02Ω 5%

1155 TA07

LTC1155

1155 TA11

1/2

LTC1155

GND

DS1

IN1

9V TO 18V

0.01Ω

IRFZ44

RISE AND FALL TIMES ARE βETA TIMES FASTER

30k

µP OR

CMOS/TTL

LOGIC

2N2222

GATE

= 2VS – 0.6V

1N41480.01µF

0.1µF

LOAD

18V

2N3906

1155 TA09

1/2

LTC1155

GND

DS1

IN1

5.2V TO 6V

0.02Ω

10µF

IRLR024

*CAPACITOR ESR SHOULD BE LESS THAN 0.5Ω

300k

0.1µF

ON/OFF

100k

0.1µF

200pF

10k

LT1431

5V/3A

470µF*

FAULT

PPLICATITYPICAL

Automotive High Side Driver with Reverse-Battery

and High Voltage Transient Protection

9V TO 16V

10µF

100k*

*PROTECTS TTL/CMOS GATES DURING HIGH VOLTAGE TRANSIENT OR REVERSE BATTERY



**NOT REQUIRED FOR INDUCTIVE OR RESISTIVE LOADS

IN1

1/2

LTC1155

GND

300Ω 1/4W

DS1

18V 1N4746A

DLY

18V 1N4746A

0.02Ω 5%

MTP50N05E

VALVE,

ETC.

1155 TA08

5V/3A Extremely Low Voltage Drop Regulator with 10µA Standby

Current and Short-Circuit Protection

Using the Second Channel for Fault Detection Bootstrapped Gate Drive for (100Hz < FO < 10kHz)

100k

1N4148

µP OR

CONTROL

LOGIC

ON/OFF

NOTE: DRAIN SENSE 2 IS USED TO DETECT A FAULT IN CHANNEL 1.  GATE 2 PULLS DOWN ON DRAIN SENSE 1 TO DISCHARGE  THE MOSFET AND REPORT THE FAULT TO THE µP



*NOT REQUIRED FOR RESISTIVE OR INDUCTIVE LOADS

10µF

100k

DS1FLT

IN2

IN1

4.5V TO 5.5V

LTC1155

GND

0.1µF*

DS2V

0.05Ω

30k*

SMD25N05-45L

LOAD

1155 TA10

LTC1155

PPLICATITYPICAL

Logic Controlled Boost Mode Switching Regulator with Short-Circuit Protection and 8µA Standby Current

4.75V TO 5.25V

100µF

FROM µP, ETC.

FAULT

*COILTRONICS CTX-7-52

IN1

1N4148

1/2

LTC1155

GND

68µF

DS1

0.33µF

100k

1µF

MTM25N05L

LT1170

0.02Ω

50µH*

1N5820

High Efficiency 60Hz Full-Wave Synchronous Rectifier

10.7k 1%

1.24k 1%

5V SWITCHED

12V/1A

2200µF

1155 TA12

100k

10k

110V AC

12.6VCT

MOSFETs ARE SYNCHRONOUSLY ENHANCED WHEN RECTIFIER CURRENT EXCEEDS 300mA *NO HEATSINK REQUIRED. CASES (DRAINS) CAN BE TIED TOGETHER **INTERNAL BODY DIODE OF MOSFET

0.03Ω

10Ω

10k

–

LT1006

1N4001

1N4148

10µF

1N4746A

IN1

IN2

100k

DS1

18V

LTC1155

GND

1N4148

DS2V

1N4148

18V 1N4746A

IRFZ44*

9V/3A DC

4700µF 16V

1155 TA13

LTC1155

PPLICATITYPICAL

High Efficiency 60Hz Full-Wave Synchronous Rectifier

9V/3A DC

10k

–

10k

10Ω

6.3V AC110V AC

MOSFETs ARE SYNCHRONOUSLY ENHANCED WHEN RECTIFIER CURRENT EXCEEDS 300mA *NO HEATSINK REQUIRED **INTERNAL BODY DIODE OF MOSFET

LT1006

1N4148

100k

IN1

IN2

DS2

LTC1155

GND

Push-Pull Driver with Shoot-Through Current Lockout (fO < 100Hz)

DS1V

18V

1N4746A

18V 1N4746A

4 × IRFZ44*

S D

4.5V TO 6V

S D

0.03Ω

4700µF 16V

1155 TA14

100k



HI/LO

74HC02

*OPPOSING GATE MUST DROP BELOW 2V BEFORE THE OTHER IS CHARGED

100k 

1N4148

10µF

DS1

IN1

LTC1155

IN2

GND

0.1µF

300k

DS2V

0.01Ω

IRLZ24

OUT

IRFZ24

1155 TA15

LTC1155

PPLICATITYPICAL

Full H-Bridge Driver with Shoot-Through Current Lockout and Stall Current Shutdown (fO < 100Hz)

4.5V TO 6V

10µF

DIRECTION

74HC02

DISABLE

*OPPOSING GATES ARE HELD OFF UNTIL OTHER GATES DROP BELOW 1.5V

DS1

IN1

LTC1155

IN2

GND

DC Motor Speed and Torque Control for Cordless Tools and Appliances

10k

SPEED

100Ω

120k

47µF 16V

100k

LT1017

–

1/2

ADJUST

LT1017

–

1/2

0.1µF

DS2V

100k

IN1

IN2

DS1

VN2222L

LTC1155

GND

0.01Ω

IRLZ44

IRFZ44

0.1µF

300k

DS2V

SMALL DC APPLIANCE

OR TOOL MOTOR

IRLZ44

IRFZ44

1155 TA16

1.1k

10k TORQUE ADJUST

0.1Ω

1A TO 10A MAX

IRFZ24

0.0033µF

SPEED IS PROPORTIONAL TO PULSE WIDTH. TORQUE IS PROPORTIONAL TO CURRENT

100k

1155 TA17

PACKAGEDESCRIPTI

0.300 BSC

(0.762 BSC)

0.008 – 0.018

(0.203 – 0.457)

NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE  OR TIN PLATE LEADS

0° – 15°

(1.143 – 1.727)

0.045 – 0.068

FULL LEAD

OPTION

CORNER LEADS OPTION 

Dimensions in inches (milimeters) unless otherwise noted.

J8 Package

8-Lead CERDIP (Narrow 0.300, Hermetic)

(LTC DWG # 05-08-1110)

(4 PLCS)

0.023 – 0.045

(0.584 – 1.143)

HALF LEAD

OPTION

0.045 – 0.068

(1.143 – 1.727)



0.014 – 0.026

(0.360 – 0.660)

0.015 – 0.060

(0.381 – 1.524)

0.100 ± 0.010

(2.540 ± 0.254)

0.200

(5.080)

MAX

0.125

3.175 MIN

0.005

(0.127)

MIN

0.025

(0.635)

RAD TYP

0.405

(10.287)

MAX

LTC1155

0.220 – 0.310

(5.588 – 7.874)

J8 1197

0.300 – 0.325

(7.620 – 8.255)

0.065

(1.651)

0.009 – 0.015

(0.229 – 0.381)

+0.035

0.325

–0.015

+0.889

8.255

()

–0.381

*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)

TYP

0.045 – 0.065

(1.143 – 1.651)

0.100 ± 0.010

(2.540 ± 0.254)

8-Lead Plastic Small Outline (Narrow 0.150)

0.010 – 0.020

(0.254 – 0.508)

0.008 – 0.010

(0.203 – 0.254)

*

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  

× 45°

0.016 – 0.050

0.406 – 1.270

0.053 – 0.069

(1.346 – 1.752)

0°– 8° TYP

0.014 – 0.019

(0.355 – 0.483)

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.

N8 Package

8-Lead PDIP (Narrow 0.300)

(LTC DWG # 05-08-1510)

0.130 ± 0.005

(3.302 ± 0.127)

0.125

0.020

(3.175)

MIN

(0.508)



0.018 ± 0.003

(0.457 ± 0.076)

MIN

S8 Package

(LTC DWG # 05-08-1610)

0.004 – 0.010

(0.101 – 0.254)

0.050

(1.270)

TYP

0.255 ± 0.015* (6.477 ± 0.381)

0.228 – 0.244

(5.791 – 6.197)



876



1234

0.189 – 0.197* (4.801 – 5.004)

0.400* (10.160)

MAX

N8 1197

0.150 – 0.157** (3.810 – 3.988)

SO8 0996

LTC1155

PPLICATITYPICAL

6V TO 12V

Isolated High Voltage High Side Switch with Circuit Breaker

1N4148

1/6 74C14

100k

100pF

0.0022µF

ON/OFF

*PICO ELECTRONICS F-28115 OR EQUIVALENT

1N4148

1/6 74C14

100k

1N4148

1/6 74C14

0.1µF

200V

1N5817

10mA

CONTROL

10µF 25V

4N28

DS1

IN1

IN2

Isolated Solid-State AC Relay with Circuit Breaker

0.1µF

1N5817

300Ω 600Ω

T1*

5.6V

1N4690A

1µF

100k

DS1

IN1

IN2

LTC1155

GND

LTC1155

GND

IN/OUT ON/OFF

90V

DS2V

1N4746A

0.01µF

DS2V

2N2222

18V 1N4746A

MUR420

18V

EQUIVALENT FUNCTION

18V

1N4746A

100k

IN/OUT

IN/OUT 24V AC 2A MAX

6A MAX

0.1Ω

1155 TA18

IRFZ24

0.05Ω

IRFZ24

IN/OUT

1155 TA19

RELATED PARTS

PART NUMBER DESCRIPTION COMMENTS

LTC1153 Auto-Reset Electronic Circuit Breaker Programmable Trip Current, Fault Status Output LT1161 Quad Protected High Side MOSFET Driver 8V to 48V Supply Range, Individual Short-Circuit Protection LTC1163 Triple 1.8V to 6V High Side MOSFET Driver 0.01µA Standby Current, Triple Driver in SO-8 Package LTC1255 Dual 24V High Side MOSFET Driver Operates from 9V to 24V, Short-Circuit Protection LTC1477 Protected Monolithic High Side Switch Low R LTC1623 SMBus Dual High Side Switch Controller 2-Wire SMBus Serial Interface, Built-In Gate Charge Pumps LTC1710 SMBus Dual Monolithic High Side Switch Two Low R

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

(408) 432-1900 ● FAX: (408) 434-0507

●

www.linear-tech.com

0.07Ω Switch, 2A Short-Circuit Protected

DS(ON)

0.4Ω/300mA Switches in 8-Lead MSOP Package

DS(ON)

1155fa LT/TP 0399 2K REV A • PRINTED IN USA

 LINEAR TECHNOLOGY CORPORATION 1991

Datasheet LTC1155 Datasheet (LINEAR TECHNOLOGY)

Specifications and Main Features

Frequently Asked Questions

User Manual