Analog Devices Inc. LT1161ISW#TRPBF

Overview

LT1161ISW#TRPBF from Analog Devices (formerly Linear Technology) is a quad protected high-side N-channel MOSFET driver IC designed for industrial, avionics, and automotive power switching applications. It features four independent channels, each with an integrated charge pump (750 kHz), individual short-circuit protection, programmable current limit (65 mV threshold), automatic restart timers, and flowthrough pinout. It operates from 8V to 48V supply and withstands –15V to 60V transients.

For engineers reviewing the LT1161ISW#TRPBF datasheet, LT1161ISW#TRPBF pinout, LT1161ISW#TRPBF application, or LT1161ISW#TRPBF equivalent, key selection criteria include its self-contained gate drive (12 V above V+), drain-sense–based fault detection, timer capacitor–programmable restart period, and SO-20 wide-body package compatibility with harsh-environment PCB layouts.

Technical Context

The LT1161ISW#TRPBF implements four fully independent high-side switch channels, each integrating a dedicated oscillator-based charge pump, a supply-referenced drain sense comparator (65 mV nominal threshold), and a timer circuit driven by external CT capacitors. Each channel's gate output is actively pulled low during overcurrent events, with timing governed by a 14 µA current source charging CT to a 3 V threshold.

Its input pins are TTL/CMOS-compatible (1.4 V threshold with 200 mV hysteresis), defaulting OFF via internal 75 kΩ pull-downs; gate drive voltage is regulated to ~12 V above V+ across 8–48 V supply range, and sense pins require Kelvin connection to V+ pins for accurate current monitoring.

Key Specifications

Pinout & Package

LT1161ISW#TRPBF is housed in a 20-lead plastic SO wide-body package (SW), optimized for thermal performance and board-level ruggedness in high-current switching applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-side MOSFET driver applications.

Compared with LT1161ISW#TRPBF, LTC1910 offers simpler single-channel fault signaling but no quad integration or CT-based recovery tuning, while TPS27081AQPWPRQ1 adds automotive diagnostics and qualification at the cost of reduced voltage range and fixed protection behavior.

Availability

LT1161ISW#TRPBF is available at Aetrix Electronics and suitable for industrial control, avionics power distribution, and automotive solenoid switching requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for LT1161ISW#TRPBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices acquired Linear Technology in 2017 and maintains full product support, datasheets, and application engineering for legacy Linear parts including the LT1161 family.

The LT1161 belongs to Linear's protected high-side driver product line, engineered specifically for ruggedized power switching in environments with poor supply regulation, EMI, and voltage transients - targeting industrial, avionics, and heavy-duty automotive systems.

FAQ

What is the maximum supply voltage rating for LT1161ISW#TRPBF?

The LT1161ISW#TRPBF is rated for continuous operation from 8 V to 48 V, with absolute maximum survival up to –15 V to +60 V on its V+ pins. This makes LT1161ISW#TRPBF suitable for automotive battery systems subject to load-dump transients and industrial 48 V DC buses. Exceeding +60 V even momentarily may cause permanent damage.

How does LT1161ISW#TRPBF implement current limiting and fault recovery?

LT1161ISW#TRPBF uses a supply-referenced comparator on each SENSE pin with a 65 mV nominal threshold to detect overcurrent. When exceeded, it pulls the corresponding TIMER pin low and disables the GATE output. Recovery is controlled by an external CT capacitor charged by a 14 µA current source to 3 V - setting the auto-restart period. LT1161ISW#TRPBF thus combines precise current sensing with user-tunable fault hold-off time.

Can LT1161ISW#TRPBF drive logic-level MOSFETs at low supply voltages?

Yes - LT1161ISW#TRPBF can drive logic-level N-channel MOSFETs down to 8 V supply. Its charge pump delivers ~12 V above V+, so at V+ = 8 V, gate drive reaches ~20 V - sufficient for most logic-level devices (e.g., IRLZ44N). For standard MOSFETs requiring ≥10 V VGS(th), operation below 12 V supply is not recommended unless using logic-level types.

What is the purpose of the dual V+ and dual GND pins on LT1161ISW#TRPBF?

The dual V+ (Pins 11, 20) and dual GND (Pins 1, 10) pins on LT1161ISW#TRPBF are internally connected and must be externally shorted. They serve two critical roles: (1) delivering operating current with low-impedance power distribution, and (2) providing Kelvin connections for the drain sense comparators - ensuring accurate current measurement by referencing sense inputs directly to the supply rail at the shunt resistor.

Is LT1161ISW#TRPBF compatible with PCB trace shunts for current sensing?

Yes - LT1161ISW#TRPBF's drain sense threshold has a +0.33%/°C temperature coefficient, closely matching that of 1 oz. copper PCB traces (~+0.39%/°C). This enables highly stable "free" current sensing using calibrated copper shunts. For example, a 0.02" wide × 2" long 1 oz. copper trace yields ~50 mΩ and supports ~2.5 A trip current with LT1161ISW#TRPBF's 65 mV threshold.