Analog Devices Inc. LT3757HMSE#PBF

Overview

LT3757HMSE#PBF from Analog Devices is a wide-input, current-mode DC/DC controller for boost, flyback, SEPIC, and inverting topologies, supporting 2.9V–40V input, programmable 50kHz–1MHz switching frequency, and ±1µA shutdown current. It drives external N-channel MOSFETs with an internal 7.2V LDO and operates up to 150°C junction temperature for automotive-grade power conversion.

For engineers reviewing the LT3757HMSE#PBF datasheet, LT3757HMSE#PBF pinout, LT3757HMSE#PBF application, or LT3757HMSE#PBF equivalent, this page delivers verified technical context, package-specific pin functions, real-world converter configurations, and validated alternative options for high-reliability industrial and automotive power designs.

Technical Context

The LT3757HMSE#PBF 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 single-pin FBX programming of both polarity configurations without external logic.

It integrates a 7.2V low-dropout regulator for gate drive, programmable UVLO with hysteresis on SHDN/UVLO, soft-start via external capacitor on SS, and frequency foldback during overcurrent. The SYNC pin supports external clock synchronization when RT is set 20% below target frequency.

Key Specifications

Pinout & Package

LT3757HMSE#PBF uses the thermally enhanced 10-lead MSOP package (3mm × 3mm) with exposed pad (Pin 11) tied to GND. The exposed pad must be soldered directly to a large copper area for thermal conduction and serves as the SENSE return path.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LT3757AEMSE#PBF, the LT3757HMSE#PBF adds 25°C higher junction rating and automotive qualification; versus LT8330EMSE#PBF, it trades integrated FET for topology flexibility, external FET optimization, and full programmability - essential for high-reliability, multi-topology, high-temperature power systems.

Availability

LT3757HMSE#PBF is available at Aetrix Electronics and suitable for automotive LED drivers, industrial flyback PSUs, portable medical chargers, and telecom intermediate bus converters requiring stable component supply across extended temperature and long production lifecycles.

Supply support for LT3757HMSE#PBF 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 precision instrumentation, industrial automation, communications, and automotive markets.

The LT3757 family was designed specifically for high-efficiency, wide-input DC/DC controllers in harsh-environment applications - emphasizing thermal robustness, topology flexibility, and automotive-grade reliability from a single IC platform.

FAQ

What is the maximum junction temperature rating for LT3757HMSE#PBF?

The LT3757HMSE#PBF is rated for a maximum junction temperature of +150°C and is AEC-Q100 qualified for automotive Grade H operation. This rating is enabled by its thermally enhanced 10-lead MSOP package with exposed pad, which achieves θJA = 40°C/W when properly soldered to a PCB ground plane. Operation above 125°C requires derating per Analog Devices' lifetime guidelines.

Can LT3757HMSE#PBF generate both positive and negative output voltages?

Yes, the LT3757HMSE#PBF supports both polarities using a single FBX pin: it automatically detects whether the external resistor divider pulls FBX toward +1.6V (for positive outputs in boost/flyback/SEPIC) or –0.8V (for negative outputs in inverting configurations). No external mode selection or pin strapping is required - the internal comparators A1 and A2 handle polarity detection and error amplification accordingly.

How does the LT3757HMSE#PBF implement frequency synchronization?

The LT3757HMSE#PBF uses the SYNC pin to accept an external digital clock signal. When active, the internal oscillator locks to the SYNC frequency - but only if the RT resistor is set to program a free-running frequency ~20% slower than the SYNC signal. The SYNC pulse must exceed 200ns minimum width. 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 LT3757HMSE#PBF package?

The exposed pad (Pin 11) on the LT3757HMSE#PBF serves three critical functions: it is the primary thermal conduction path to the PCB (reducing θJA to 40°C/W), the electrical ground reference for the IC, and the Kelvin return path for the SENSE current. It must be soldered directly to a large copper ground plane - not left floating or connected only through vias - to ensure thermal integrity and accurate current sensing.

Does LT3757HMSE#PBF include overvoltage protection for the output?

Yes, the LT3757HMSE#PBF includes dual overvoltage protection on the FBX pin: a +8% comparator triggers when FBX exceeds +1.6V (i.e., >1.728V), and a –11% comparator triggers when FBX falls below –0.8V (i.e., <–0.888V). Both generate reset pulses that hold the GATE pin low until the fault clears - protecting downstream loads during startup overshoot or short-circuit recovery without requiring external circuitry.