Analog Devices Inc. LT3757AHMSE#TRPBF

Overview

LT3757AHMSE#TRPBF from Analog Devices is a wide-input, current-mode DC/DC controller for boost, flyback, SEPIC, and inverting topologies, driving external N-channel MOSFETs with an internal 7.2V LDO gate driver. It supports 2.9V–40V input, programmable 50kHz–1MHz switching frequency, and operates across –40°C to 150°C junction temperature. Used in automotive power supplies requiring high reliability under thermal stress.

For engineers reviewing the LT3757AHMSE#TRPBF datasheet, LT3757AHMSE#TRPBF pinout, LT3757AHMSE#TRPBF application, or LT3757AHMSE#TRPBF equivalent, key selection criteria include its AEC-Q100 qualification, negative/positive output voltage programming via single FBX pin, soft-start and frequency foldback for short-circuit protection, and thermally enhanced MSOP-10 package with exposed pad.

Technical Context

The LT3757AHMSE#TRPBF implements fixed-frequency current-mode control with slope compensation, enabling stable regulation across wide VIN and VOUT ranges. Its dual feedback reference (1.6V for positive outputs, –0.8V for negative outputs) allows topology-agnostic configuration without external logic.

It integrates a 7.2V low-dropout regulator for gate drive, programmable UVLO with hysteresis on SHDN/UVLO, and synchronous capability via the SYNC pin-requiring RT biasing 20% below external clock frequency. Frequency foldback and soft-start clamp VC during fault and startup to limit inductor current.

Key Specifications

Pinout & Package

LT3757AHMSE#TRPBF uses a thermally enhanced 10-lead MSOP package (3mm × 3mm) with exposed pad (Pin 11) that must be soldered to PCB ground for thermal and electrical integrity. The exposed pad serves as both thermal path and SENSE return reference.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT3757EMSE#TRPBF, the LT3757AHMSE#TRPBF adds guaranteed 150°C operation and AEC-Q100 compliance-critical for automotive under-hood use-while LT3757AEMSE#TRPBF provides identical specs in a smaller DFN package, trading thermal resistance for board area savings.

Availability

LT3757AHMSE#TRPBF is available at Aetrix Electronics and suitable for automotive LED drivers, industrial isolated PSUs, portable medical imaging power, and telecom boost converters requiring stable component supply with long-term lifecycle assurance.

Supply support for LT3757AHMSE#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, communications, and automotive markets.

The LT3757A product line delivers robust, wide-input DC/DC controllers optimized for demanding power conversion in automotive, industrial, and telecom applications-emphasizing reliability, thermal resilience, and topology flexibility.

FAQ

What is the maximum junction temperature rating for LT3757AHMSE#TRPBF?

The LT3757AHMSE#TRPBF is rated for operation up to +150°C junction temperature and is fully qualified per AEC-Q100 Grade H. This specification is guaranteed across the full –40°C to +150°C operating range, with thermal protection engaging above this threshold to prevent permanent damage. Designers must ensure proper PCB thermal design-including soldering the exposed pad-to maintain safe junction temperatures under load.

How does the FBX pin support both positive and negative output voltages in LT3757AHMSE#TRPBF?

The LT3757AHMSE#TRPBF uses a dual-reference architecture on the FBX pin: it regulates to +1.6V for boost, flyback, or SEPIC configurations (positive outputs), and to –0.8V for inverting topologies (negative outputs). The internal comparators A1 and A2 automatically select the appropriate reference based on FBX voltage polarity-no external components or mode pins are required. This enables seamless topology reconfiguration with only feedback divider changes.

Can LT3757AHMSE#TRPBF synchronize to an external clock, and what are the requirements?

Yes, the LT3757AHMSE#TRPBF supports synchronization via the SYNC pin. To enable sync mode, an external clock signal (digital, 0–8V swing) must be applied to SYNC, and the RT resistor must be selected to program a free-running frequency ~20% lower than the SYNC frequency. The SYNC pulse width must exceed 200ns. If unused, SYNC must be tied to GND-leaving it floating may cause erratic operation.

What is the purpose of the exposed pad on the LT3757AHMSE#TRPBF MSOP package?

The exposed pad (Pin 11) on the LT3757AHMSE#TRPBF serves two critical functions: it is the electrical ground reference for the SENSE pin and the primary thermal conduction path from the die to the PCB. It must be soldered directly to a solid copper ground plane to achieve the specified θJA of 40°C/W. Failure to solder the pad results in excessive junction temperature rise and potential thermal shutdown or reliability degradation during continuous operation.

Does LT3757AHMSE#TRPBF include built-in overvoltage protection, and how does it work?

Yes, the LT3757AHMSE#TRPBF includes dual overvoltage protection on the FBX pin: one comparator triggers at +8% above the +1.6V reference (i.e., >1.728V), and another at +11% above the –0.8V reference (i.e., <–0.888V). Both generate reset pulses that force the GATE pin low and hold the power switch off until FBX returns within safe bounds. This protects downstream loads during startup overshoot or output short-circuit recovery without requiring external circuitry.