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LTC1154

1154fb

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

High Side Micropower

MOSFET Driver

The LTC

1154 single high side gate driver allows using low

cost N-channel FETs for high side switching applications. An

internal charge pump boosts the gate drive voltage above

the positive rail, fully enhancing an N-channel MOS switch

with no external components. Micropower operation, with

8μA standby current and 85μA operating current, allows

use in virtually all systems with maximum efﬁ ciency.

Included on chip is programmable overcurrent sensing.

A time delay can be added to prevent false triggering on

high inrush current loads. An active high shutdown input

is also provided and interfaces directly to a standard PTC

thermistor for thermal shutdown. An open-drain output

is provided to report switch status to the μP. An active

low enable input is provided to control multiple switches

in banks.

The LTC1154 is available in both 8-pin DIP and 8-pin SOIC

packages.

Ultralow Voltage Drop High Side Switch with

Short-Circuit Protection

Fully Enhances N-Channel Power MOSFETs

8μA I

Standby Current

85μA I

ON Current

No External Charge Pump Capacitors

4.5V to 18V Supply Range

Short-Circuit Protection

Thermal Shutdown via PTC Thermistor

Status Output Indicates Shutdown

Available in 8-Pin SOIC and PDIP Packages

Laptop Computer Power Switching

SCSI Termination Power Switching

Cellular Telephone Power Management

Battery Charging and Management

High Side Industrial and Automotive Switching

Stepper Motor and DC Motor Control

Standby Supply Current

IRLR024

0.036Ω*

LTC1154 • TA01

LOAD

μP

200k**

0.1μF**

2.7A MAX

51k

STATUS

GND

LTC1154

ALL COMPONENTS SHOWN ARE SURFACE MOUNT.

IMS026 INTERNATIONAL MANUFACTURING SERVICE, INC. (401) 683-9700

NOT REQUIRED IF LOAD IS RESISTIVE OR INDUCTIVE.

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (μA)

515

LTC1153 • TA02

= 0V

= 25°C

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

Summary of content (18 pages)

PAGE 1
LTC1154 High Side Micropower MOSFET Driver FEATURES DESCRIPTION n The LTC®1154 single high side gate driver allows using low cost N-channel FETs for high side switching applications. An internal charge pump boosts the gate drive voltage above the positive rail, fully enhancing an N-channel MOS switch with no external components. Micropower operation, with 8μA standby current and 85μA operating current, allows use in virtually all systems with maximum efﬁciency.
PAGE 2
LTC1154 ABSOLUTE MAXIMUM RATINGS (Note 1) Supply Voltage ..........................................................22V Input Voltage.......................(VS + 0.3V) to (GND – 0.3V) Enable Input Voltage ...........(VS + 0.3V) to (GND – 0.3V) Gate Voltage .........................(VS + 24V) to (GND – 0.3V) Status Output Voltage ...............................................15V Current (Any Pin) ...................................................50mA Operating Temperature LTC1154C ........................
PAGE 3
LTC1154 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. VS = 4.5V to 18V, TA = 25°C, VEN = 0V, VSD = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN MAX UNITS 0.8 V l ±1 μA VINL Input Low Voltage IIN Input Current CIN Input Capacitance VENH ENABLE Input High Voltage l VENL ENABLE Input Low Voltage l l 0V < VIN < VS TYP l 3.5 5 pF 2.6 V 1 0.
PAGE 4
LTC1154 TYPICAL PERFORMANCE CHARACTERISTICS Standby Supply Current Supply Current ON 50 VIN = 0V TA = 25°C 45 TA = 25°C 900 22 20 800 35 30 25 20 18 700 VGATE – VS (V) SUPPLY CURRENT (μA) 40 SUPPLY CURRENT (μA) High Side Gate Voltage 24 1000 600 500 400 16 14 12 300 10 10 200 8 5 100 6 15 0 0 0 0 5 10 15 SUPPLY VOLTAGE (V) 20 0 5 LTC1154 • TPC01 5 0 20 10 15 SUPPLY VOLTAGE (V) 20 10 15 SUPPLY VOLTAGE (V) LTC1154 • TPC02 LTC1154 • TPC03 Input Threshold Voltage Drain
PAGE 5
LTC1154 TYPICAL PERFORMANCE CHARACTERISTICS Standby Supply Current Supply Current ON 50 900 VIN = 5V VEN = 0V 2.2 800 SUPPLY CURRENT (μA) 35 30 25 20 15 VS = 18V 10 700 600 500 400 VS = 12V 300 200 5 100 VS = 5V 0 –50 –25 50 25 0 75 TEMPERATURE (°C) VS = 5V 100 0 –50 125 –25 2.2 4.5 ENABLE THRESHOLD VOLTAGE (V) 5.0 2.0 1.8 1.6 VS = 5V VS = 18V 0.8 0.6 0.4 –50 25 0 50 75 TEMPERATURE (°C) 25 0 50 75 TEMPERATURE (°C) 100 125 VS = 5V 1.2 VS = 18V 1.0 0.
PAGE 6
LTC1154 PIN FUNCTIONS Gate Drive Pin Drain Sense 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. The drain sense pin is compared against the supply pin voltage.
PAGE 7
LTC1154 TRUTH TABLE INPUTS OUTPUTS SWITCH CONDITION IN EN SD X H X L H SWITCH OFF L X X L H SWITCH OFF H L L H H SWITCH ON H L L L L SWITCH LATCHED OFF (OVER CURRENT) H L L L SWITCH LATCHED OFF (SHUTDOWN) L = LOGIC LOW H = LOGIC HIGH X = IRRELEVANT GATE STATUS = EDGE TRIGGERED The Truth Table demonstrates how the LTC1154 receives inputs and returns status information to the μP.
PAGE 8
LTC1154 OPERATION 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. Status Output Driver The status circuitry continuously monitors the fault detection logic. This open-drain output is driven low when the gate of the MOSFET is driven low by the protection circuitry.
PAGE 9
LTC1154 APPLICATIONS INFORMATION Capacitive Loads Lamp Loads Large capacitive loads, such as complex electrical systems with large bypass capacitors, should be powered using the circuit shown in Figure 3. The gate drive to the power MOSFET is passed through an RC delay network, R1 and C1, which greatly reduces the turn-on ramp rate of the switch. And since the MOSFET source voltage follows the gate voltage, the load is powered smoothly and slowly from ground.
PAGE 10
LTC1154 APPLICATIONS INFORMATION The Y axis of the graph is normalized to one RC time constant. The X axis is normalized to the current. (The set current is deﬁned as the current required to develop 100mV across the drain sense resistor). 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 manufacturer for safe operation. (See MOSFET data sheet for further information).
PAGE 11
LTC1154 APPLICATIONS INFORMATION added as shown in Figure 8 which holds the supply pin of the LTC1154 high long enough for the overcurrent shutdown circuitry to respond and fully discharge the gate. Five volt linear regulators with small output capacitors are the most difﬁcult to protect as they can “switch” from a voltage mode to a current limited mode very quickly. The large output capacitors on many switching regulators may be able to hold the supply pin of the LTC1154 above 3.
PAGE 12
LTC1154 TYPICAL APPLICATIONS 24V to 28V Switch with Bootstrapped Supply 24V TO 28V High Side Relay Driver with Overcurrent Protection and Status Feedback 12V + 100μF + 100k 100μF 2Ω + 5V μP OR CONTROL LOGIC 18V IN VS EN DS 10μF 6.2k μP OR CONTROL LOGIC 1N4148 LTC1154 STATUS † VS EN DS 10k 0.01μF MTD3055E G STATUS 15V GND SD * KEYSTONE RL2006-100-100-30-PT. MOUNT ON MOSFET OR LOAD HEAT SINK. IQ(OFF) = 60MA, IQ(ON) = 1mA.
PAGE 13
LTC1154 TYPICAL APPLICATIONS Bank Controlled High Side Switches with “Global” Thermal and Overvoltage Shutdown 12V IN VS 100Ω EN + 470μF DS LTC1154 STATUS G IRLR024 15V GND SD IN VS OUTPUT 1 5V EN DS LTC1154 51k STATUS G IRLR024 15V μP OR CONTROL LOGIC GND SD IN VS EN OUTPUT 2 DS LTC1154 STATUS G IRLR024 15V GND SD IN VS EN DS OUTPUT 3 120k LTC1154 STATUS G IRLR024 15V GND SD OUTPUT 4 15V *KEYSTONE RL2006-100-100-30-PT. MOUNT ON COMMON HEAT SINK.
PAGE 14
LTC1154 TYPICAL APPLICATIONS 12V Step-Up Regulator with Ultralow Standby Current, Overcurrent Protection and Status Feedback 0.02Ω 5V + + 20Ω 470μF 47μF IN VS EN DS 10k 5 + 1N4148 VIN 150μF 1N4148 3 LTC1154 STATUS STATUS 100k 1 1.24k 1% 100k G 1k 0.1μF SD GND 10.72k 1% 4 VSW LT1070 2 FB V GND C 0.
PAGE 15
LTC1154 PACKAGE DESCRIPTION N8 Package 8-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510) .400* (10.160) MAX 8 7 6 5 1 2 3 4 .255 ± .015* (6.477 ± 0.381) .300 – .325 (7.620 – 8.255) .008 – .015 (0.203 – 0.381) ( +.035 .325 –.015 8.255 +0.889 –0.381 ) .045 – .065 (1.143 – 1.651) .130 ± .005 (3.302 ± 0.127) .065 (1.651) TYP .100 (2.54) BSC .120 (3.048) .020 MIN (0.508) MIN .018 ± .003 (0.457 ± 0.076) N8 1002 NOTE: 1.
PAGE 16
LTC1154 PACKAGE DESCRIPTION S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) .189 – .197 (4.801 – 5.004) NOTE 3 .045 ±.005 .050 BSC 8 .245 MIN 7 6 5 .160 ±.005 .150 – .157 (3.810 – 3.988) NOTE 3 .228 – .244 (5.791 – 6.197) .030 ±.005 TYP 1 RECOMMENDED SOLDER PAD LAYOUT .010 – .020 × 45° (0.254 – 0.508) .008 – .010 (0.203 – 0.254) 0°– 8° TYP .016 – .050 (0.406 – 1.270) NOTE: 1. DIMENSIONS IN .053 – .069 (1.346 – 1.752) .014 – .019 (0.355 – 0.
PAGE 17
LTC1154 REVISION HISTORY (Revision history begins at Rev B) REV DATE DESCRIPTION PAGE NUMBER B 4/11 Updated Graph TPC05 4 Updated SCSI Termination Typical Application 18 Updated Related Parts 18 1154fb Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use.
PAGE 18
LTC1154 TYPICAL APPLICATIONS Auto-Reset High Side Switch with Overcurrent and Overcurrent Temperature Shutdown 12V + RT 1M** 100μF 1M 0.036Ω ON/OFF IN VS EN + DS LTC1154 CT 100μF** MTP12N06 G STATUS VN2222LL 18V 200k SD GND PTC THERMISTOR (100°C)* *KEYSTONE RL2006-100-100-30-PT. **AUTO-RESET PERIOD ≈ 800ms WITH COMPONENTS SHOWN 12V LOAD LTC1154 • TA13 SCSI Termination Power Switch with 1A Overcurrent Shutdown, Auto-Reset and Load Soft-Start 0.