Analog Devices Inc. LT4363HS-1#TRPBF

Overview

LT4363HS-1#TRPBF from Analog Devices is a high-voltage surge stopper IC that controls an external N-channel MOSFET to regulate output voltage during overvoltage transients up to 100V, limits current via 50mV SNS–OUT sense threshold, and features latch-off fault behavior (LT4363-1 variant) for industrial power rails requiring fail-safe shutdown. It operates from 4V to 80V input, supports –60V reverse input protection, and delivers precise UV/OV monitoring with 1.275V thresholds.

For engineers reviewing the LT4363HS-1#TRPBF datasheet, LT4363HS-1#TRPBF pinout, LT4363HS-1#TRPBF application, or LT4363HS-1#TRPBF equivalent, key selection considerations include its 16-pin SO package, –40°C to 125°C operating range, adjustable 27V output clamp, fast 1µs overcurrent turn-off propagation, and latch-off response to persistent faults-critical for avionics, hot-swap systems, and intrinsic safety designs.

Technical Context

The LT4363HS-1#TRPBF implements dual-loop protection: a voltage amplifier regulates GATE to maintain 1.275V at FB during overvoltage, while a current amplifier holds ΔVSNS = 50mV (or 25mV if OUT < 2V) during overcurrent. Fault timing is dynamically scaled by VCC–OUT voltage to align with MOSFET safe operating area constraints.

It integrates precision comparators for UV (1.275V threshold, 12mV hysteresis) and OV (1.275V threshold, 7.5mV hysteresis), a 14V GATE clamp, and a TMR pin with three-phase operation: early warning (1.275V), shutdown (1.375V), and cool-down (4.3V → 0.5V). The LT4363-1 variant latches GATE low after fault timeout until SHDN reset.

Key Specifications

Pinout & Package

LT4363HS-1#TRPBF is housed in a 16-lead plastic SO package (S package), with exposed thermal pad not present. Pin functions are electrically identical to the MSOP/DFN variants but mapped to the SO footprint per datasheet Figure "S PACKAGE".

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar surge protection applications.

Compared with LT4363HS-2#TRPBF, the LT4363HS-1#TRPBF provides deterministic latch-off for certified safety systems, while TPS26631RHFR trades configurability for integration and footprint reduction - making LT4363HS-1#TRPBF optimal for regulated surge survival in high-reliability industrial and avionic power rails.

Availability

LT4363HS-1#TRPBF is available at Aetrix Electronics and suitable for avionic power distribution, industrial hot-swap modules, and intrinsic safety barrier designs requiring stable component supply across extended temperature and high-reliability lifecycles.

Supply support for LT4363HS-1#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 (now part of Analog Devices, Inc., a wholly owned subsidiary of Analog Devices, Inc.) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.

The LT4363 product line was designed specifically for ruggedized DC power protection in automotive, avionic, and industrial systems - delivering regulated surge survival, precise current limiting, and configurable fault timing in a single IC.

FAQ

What is the key functional difference between LT4363HS-1#TRPBF and LT4363HS-2#TRPBF?

The LT4363HS-1#TRPBF implements latch-off fault behavior: once the TMR pin reaches 1.375V, GATE and FLT remain low until SHDN is actively pulsed. In contrast, LT4363HS-2#TRPBF automatically restarts after TMR discharges to 0.5V during cool-down. This makes LT4363HS-1#TRPBF mandatory for safety-critical applications where uncontrolled retries are prohibited. Both share identical pinout, electrical specs, and package.

Can LT4363HS-1#TRPBF be used with back-to-back N-channel MOSFETs for reverse polarity protection?

Yes. LT4363HS-1#TRPBF supports reverse input protection down to –60V at VCC and SHDN pins, enabling robust back-to-back N-MOSFET configurations. Its ability to drive GATE up to 14V above OUT ensures reliable enhancement-mode turn-on of both FETs, eliminating forward voltage drop and heat generation associated with Schottky diodes - a key advantage in high-efficiency 48V systems.

What is the minimum TMR capacitor value required for stable operation of LT4363HS-1#TRPBF?

The datasheet specifies a minimum TMR capacitor of 10nF for loop compensation and stable regulation. Using less than 10nF may cause oscillation or erratic fault timing. For standard 27V clamp applications with 80V surges, a 6.8µF capacitor yields ~100ms total fault time (tFLT + tWARNING), as validated in the Typical Application circuit (Figure 4363 TA01b). Always verify timing with actual VCC–OUT waveform.

How does the LT4363HS-1#TRPBF achieve precise current limiting without external op-amps?

LT4363HS-1#TRPBF integrates a dedicated current amplifier (IA) that servo-controls GATE to hold ΔVSNS = 50mV (±5%) across the sense resistor. When OUT drops below 2V during a hard short, the amplifier folds back to 25mV - reducing MOSFET power dissipation by half. This closed-loop architecture eliminates drift and offset errors inherent in discrete solutions, delivering consistent current limit accuracy from –40°C to +125°C.

Is the OV pin used on LT4363HS-1#TRPBF, and what should be done with it?

No - the OV pin is exclusive to LT4363-2 variants and is not functional on LT4363HS-1#TRPBF. Per the datasheet Pin Functions section, the OV pin must be connected to GND on LT4363-1 devices to prevent floating inputs and ensure predictable comparator behavior. Leaving it unconnected may cause erratic UV/OV monitoring or increased leakage current.