Analog Devices Inc. LT3752IFE#TRPBF

Overview

LT3752IFE#TRPBF from Analog Devices is a current-mode PWM controller optimized for active clamp forward converter topologies, featuring integrated housekeeping DC/DC control, programmable volt-second clamp (enabling >50% primary duty cycle), active clamp switch timing control (AOUT), and synchronous rectification drive (SOUT). It operates from 6.5V to 100V input and supports 100–500kHz switching frequency. Used in isolated 48V telecom power supplies delivering up to 150W at 94% efficiency.

For engineers reviewing the LT3752IFE#TRPBF datasheet, LT3752IFE#TRPBF pinout, LT3752IFE#TRPBF application, or LT3752IFE#TRPBF equivalent, key selection criteria include its dual-loop architecture (forward + housekeeping), programmable tAO/tOA/tSO/tOS timing delays, 38-lead TSSOP package with high-voltage pin spacing, AEC-Q100 qualification, and support for active clamp MOSFET gate drive with <25ns rise/fall times.

Technical Context

The LT3752IFE#TRPBF implements a dual-controller architecture: a main forward controller (OUT/AOUT/SOUT) with adaptive leading-edge blanking, programmable volt-second clamp (DVSEC), and cycle-by-cycle current sensing on ISENSEP/ISENSEN; plus an independent housekeeping controller (HOUT/HCOMP/HFB) with soft-start, hiccup-mode overcurrent protection, and output voltage regulation via HFB reference (1.000V). Both loops share RT-based oscillator synchronization but operate at independently foldback-capable frequencies.

Its active clamp topology reduces primary switch voltage stress by recycling leakage energy into a clamp capacitor, while synchronous rectification control (SOUT) minimizes secondary-side conduction losses. The device supports precise timing coordination-tAO (AOUT-to-OUT delay), tOS (OUT-to-SOUT delay), and tSO (SOUT-to-OUT delay)-via external resistors (RTAO, RTOS, RTAS), enabling optimization of ZVS/ZCS transitions in high-efficiency isolated designs.

Key Specifications

Pinout & Package

The LT3752IFE#TRPBF is housed in a 38-lead plastic TSSOP (FE package) with missing pins for enhanced high-voltage creepage and clearance. Exposed pad (Pin 39) is connected to PGND/GND and must be soldered to PCB for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar active clamp forward controller applications.

Compared with LT3751IFE#TRPBF and UCC2897APWR, the LT3752IFE#TRPBF delivers higher integration (dual-loop control), superior timing granularity (individual AOUT/SOUT/OUT delay programming), and broader input range support (100V vs. 60V), making it optimal for space-constrained, high-efficiency isolated power where auxiliary rail generation and precise ZVS tuning are critical.

Availability

LT3752IFE#TRPBF is available at Aetrix Electronics and suitable for telecom 48V isolated PSUs, automotive ADAS power modules, and industrial offline power supplies requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant manufacturing.

Supply support for LT3752IFE#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LT3752 product line was designed specifically for high-efficiency active clamp forward converters in isolated power applications demanding dual-loop control, precise timing, and rugged operation across extended temperature ranges.

FAQ

What is the maximum input voltage rating for the LT3752IFE#TRPBF?

The LT3752IFE#TRPBF has an absolute maximum input voltage (VIN) rating of 100V, with guaranteed operational range from 6.5V to 100V. This makes it suitable for high-input industrial and telecom applications where transient overvoltage immunity is critical. The LT3752IFE#TRPBF variant is distinct from the LT3752-1 family, which is optimized for >100V inputs using different internal regulators.

How does the LT3752IFE#TRPBF implement active clamp timing control?

The LT3752IFE#TRPBF uses dedicated AOUT and OUT drivers with programmable delays: tAO (AOUT-to-OUT rise), tOA (OUT fall-to-AOUT edge), and tOS (OUT fall-to-SOUT rise), each set by external resistors (RTAO, RTAS, RTOS). These delays coordinate ZVS transitions by controlling clamp capacitor discharge/recharge timing relative to main switch operation, directly reducing switching losses in the active clamp forward topology.

Does the LT3752IFE#TRPBF include an integrated auxiliary power supply controller?

Yes, the LT3752IFE#TRPBF integrates a complete housekeeping DC/DC controller with HOUT driver, HFB feedback pin (1.000V reference), HCOMP compensation node, and HISENSE current sense input. This eliminates the need for an external bias supply, simplifying design and improving efficiency in isolated forward converters requiring auxiliary rails for gate drivers or control circuitry.

What package type and thermal characteristics does the LT3752IFE#TRPBF use?

The LT3752IFE#TRPBF uses a 38-lead plastic TSSOP (FE package) with an exposed thermal pad (Pin 39) tied to PGND/GND. Its thermal resistance is θJA = 25°C/W when properly soldered to a 4-layer PCB with adequate copper pour, enabling full-load operation at +125°C junction temperature without additional heatsinking in well-designed layouts.

Is the LT3752IFE#TRPBF qualified for automotive applications?

Yes, the LT3752IFE#TRPBF is AEC-Q100 qualified (Grade I: –40°C to +125°C junction temperature) and manufactured with automotive-grade process controls. It supports automotive use cases including ADAS power modules and infotainment system DC/DC converters, with features like hiccup-mode overcurrent protection, precise UVLO/OVLO thresholds, and robust EMI performance.