Analog Devices Inc. LTC4352HMS#TRPBF

Overview

LTC4352HMS#TRPBF from Analog Devices (formerly Linear Technology) is a high-temperature ideal diode controller that drives an external N-channel MOSFET to replace Schottky diodes in ORing and holdup applications. It operates from 2.9V to 18V input, regulates forward voltage drop to 25mV typical, achieves 0.5μs turn-on/turn-off, and supports reverse current enable via REV pin. It is used in telecom power redundancy and hot-swap server supplies.

For engineers reviewing the LTC4352HMS#TRPBF datasheet, LTC4352HMS#TRPBF pinout, LTC4352HMS#TRPBF application, or LTC4352HMS#TRPBF equivalent, key selection criteria include its –40°C to 150°C operating range, open-MOSFET fault detection at 250mV, UV/OV protection thresholds, STATUS/FAULT open-drain outputs, and MSOP-12 package compatibility with thermal design for high-reliability industrial systems.

Technical Context

The LTC4352HMS#TRPBF implements a servo-controlled amplifier that regulates VIN–OUT to 25mV by dynamically adjusting gate drive to maintain low conduction loss. Its internal charge pump (CPO) enables fast 0.5μs MOSFET turn-on using an external CPO–SOURCE capacitor, while GATE clamp limits voltage to 6.1V above SOURCE.

It integrates three independent comparators: UV (0.5V threshold), OV (0.5V threshold), and VCC UVLO (2.57V), all with built-in hysteresis. The REV pin overrides diode behavior by forcing full gate enhancement, enabling controlled reverse current flow-critical for bidirectional power path management in back-to-back MOSFET configurations.

Key Specifications

Pinout & Package

Package: 12-Lead Plastic MSOP (3.0mm × 4.0mm × 1.1mm height), exposed pad optional, RoHS-compliant, tape-and-reel (TRPBF).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ideal diode controller applications.

Compared with LTC4352HMS#TRPBF, LTC4355IDE#TRPBF supports higher input voltages but sacrifices reverse-current enable and extended temperature capability, while LTC4357IMS8#TRPBF reduces footprint and quiescent current at the cost of integrated UV/OV protection and fault diagnostics.

Availability

LTC4352HMS#TRPBF is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, and automotive ADAS domain controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC4352HMS#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 its precision analog and power management portfolio with full backward compatibility and long-term product support.

The LTC4352HMS#TRPBF belongs to Linear's PowerPath™ ideal diode controller family, engineered for high-efficiency, high-reliability power ORing and holdup in mission-critical telecom, industrial, and automotive systems.

FAQ

What is the maximum junction temperature specification for the LTC4352HMS#TRPBF?

The LTC4352HMS#TRPBF is rated for continuous operation up to TJ = 150°C, confirmed by its H-grade temperature marking and absolute maximum rating table. This allows direct integration into thermally constrained environments such as sealed telecom power shelves or under-hood automotive ECUs without thermal derating. The MSOP-12 package's θJA = 164°C/W requires careful PCB copper pour design to sustain full-load operation at ambient 85°C.

How does the REV pin function in the LTC4352HMS#TRPBF, and what voltage level activates it?

The REV pin on the LTC4352HMS#TRPBF enables controlled reverse current flow by overriding the ideal diode behavior. When driven above 0.8V (minimum, per H-grade spec), it forces full gate enhancement regardless of VIN–OUT polarity. This allows bidirectional conduction - essential for battery backup, regenerative braking, or dual-supply arbitration. Below 0.8V, normal diode operation resumes. The pin has a 10μA internal pull-down, so floating defaults to blocking mode.

Can the LTC4352HMS#TRPBF operate with input voltages below 2.9V, and if so, how?

Yes, the LTC4352HMS#TRPBF can operate with VIN < 2.9V by supplying an external 2.9V–6V voltage to the VCC pin. In this configuration, the internal LDO is disabled (CP4 comparator disables it), and VCC powers all internal circuitry. A 0.1μF bypass capacitor remains mandatory between VCC and GND. This mode supports 0V–18V input ORing, such as battery-backed 1.8V or 3.3V rails, provided the external VCC supply is always present or sequenced correctly.

What is the purpose of the CPO pin on the LTC4352HMS#TRPBF, and how is its capacitor sized?

The CPO pin on the LTC4352HMS#TRPBF delivers stored charge for fast MOSFET turn-on. It connects externally to SOURCE via a capacitor sized to ~10× the MOSFET's input capacitance (CISS). For example, with Si7336ADP (CISS ≈ 6500pF), a 0.1μF capacitor is recommended. Too small a value causes excessive voltage droop during gate pull-up; too large delays charge time. The internal charge pump ramps CPO at ~10μA, so 0.1μF charges in ~10ms - acceptable for most start-up scenarios.

How does the LTC4352HMS#TRPBF detect and respond to an open MOSFET fault?

The LTC4352HMS#TRPBF detects an open MOSFET fault when VIN–OUT exceeds 250mV (VFWD(FLT)), indicating either excessive RDS(ON) or MOSFET failure. It pulls the FAULT pin low but leaves the MOSFET ON - unlike UV/OV faults which disable conduction. This design allows continued power delivery while alerting the system to potential degradation. The threshold is fixed and applies across the full –40°C to 150°C range, ensuring reliable early-warning detection in high-temp environments.