Analog Devices Inc. LT1952EGN-1#TRPBF

Overview

LT1952EGN-1#TRPBF from Analog Devices (formerly Linear Technology) is a current-mode synchronous forward controller IC optimized for single-MOSFET forward converters. It delivers programmable 100–500 kHz switching, precision 107 mV overcurrent threshold, adaptive volt-second clamp, and dual gate drivers (OUT ±1 A, SOUT ±50 mA) for high-efficiency telecom bus converters (e.g., 36–72 V input to 12 V/20 A).

For engineers reviewing the LT1952EGN-1#TRPBF datasheet, LT1952EGN-1#TRPBF pinout, LT1952EGN-1#TRPBF application, or LT1952EGN-1#TRPBF equivalent, key selection criteria include its VIN start-up current (400 µA), SD_VSEC UVLO hysteresis (0.95–1.25 V), adjustable synchronous delay (40–120 ns), true op-amp COMP amplifier, and 16-pin SSOP package compatibility with isolated DC/DC designs requiring >50% duty cycle operation.

Technical Context

The LT1952EGN-1#TRPBF implements current-mode PWM control with an internal 200 kHz nominal oscillator (programmable 100–500 kHz via ROSC), synchronized externally up to 1.5× fOSC. Its adaptive volt-second clamp uses SD_VSEC and SS_MAXDC pins-resistively derived from input voltage-to dynamically limit maximum duty cycle and prevent transformer saturation without external capacitors.

It features dual independent gate drivers: OUT (±1 A, 13 V clamp) for primary-side N-MOSFET, and SOUT (±50 mA, 12 V clamp) for secondary-side synchronous rectifiers, with programmable tDELAY (via DELAY pin resistor) to align timing for peak efficiency. The 107 mV OC threshold and leading-edge blanking (via BLANK pin) provide hiccup-mode short-circuit protection independent of duty cycle.

Key Specifications

Pinout & Package

LT1952EGN-1#TRPBF is housed in a 16-pin plastic SSOP (GN) package with 0.65 mm pitch, rated for –40°C to +125°C junction temperature. Thermal resistance θ_JA = 110°C/W, θ_JC = 40°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT3748EMSE#TRPBF and UCC2891DR, the LT1952EGN-1#TRPBF uniquely combines programmable synchronous delay, resistor-based volt-second clamp, and dual independent gate drivers-making it optimal for high-efficiency, space-constrained forward converters needing >50% duty cycle operation without external timing capacitors.

Availability

LT1952EGN-1#TRPBF is available at Aetrix Electronics and suitable for telecommunications power supplies, industrial isolated DC/DC converters, and high-density server intermediate bus converters requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LT1952EGN-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 (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving precision instrumentation, communications, and industrial markets.

The LT1952EGN-1#TRPBF belongs to Linear's legacy high-efficiency power controller product line, designed specifically for synchronous forward converters in telecom and industrial infrastructure where reliability, efficiency, and compact design are critical.

FAQ

What is the key functional difference between LT1952EGN-1#TRPBF and LT1952EGN#TRPBF?

The LT1952EGN-1#TRPBF features lower VIN undervoltage lockout thresholds (7.75 V ON / 6.5 V OFF) and reduced start-up current (400 µA typ) versus the LT1952EGN#TRPBF (14.25 V ON / 8.75 V OFF, 460 µA). This makes the -1 variant suitable for systems with lower input voltage rails or tighter power budget constraints during startup. Both share identical pinout, package, and core control architecture.

How does the SD_VSEC pin implement volt-second clamping in LT1952EGN-1#TRPBF?

In the LT1952EGN-1#TRPBF, the SD_VSEC pin voltage-derived from a resistor divider across the transformer input-directly modulates the adaptive maximum duty cycle clamp. As input voltage rises, SD_VSEC voltage increases, causing the clamp to decrease proportionally. This prevents transformer saturation without external timing capacitors, enabling safe >50% duty cycle operation across wide input ranges.

Can LT1952EGN-1#TRPBF drive both primary and secondary MOSFETs directly?

Yes-the LT1952EGN-1#TRPBF integrates two independent gate drivers: OUT (±1 A, 13 V clamp) for the primary-side N-MOSFET, and SOUT (±50 mA, 12 V clamp) for secondary-side synchronous rectifiers. SOUT timing is programmable via the DELAY pin resistor to optimize conduction overlap and minimize body-diode losses in forward topologies.

What is the purpose of the BLANK pin on LT1952EGN-1#TRPBF?

The BLANK pin on LT1952EGN-1#TRPBF controls programmable leading-edge blanking duration (180–540 ns) for both the current-sense comparator and OC comparator. A resistor to ground sets the blanking window, suppressing false triggering caused by MOSFET switching noise during turn-on-critical for stable operation with high dV/dt layouts.

Does LT1952EGN-1#TRPBF require an external reference voltage?

No-LT1952EGN-1#TRPBF includes an internal 2.5 V reference (VREF pin, Pin 6) capable of sourcing up to 2.5 mA for external biasing, and a separate 1.226 V internal reference for the FB pin. External references are optional; the device operates fully self-contained with only a 0.1 µF ceramic capacitor on VREF for stability.