Analog Devices Inc. LTC3862HFE-1#PBF

Overview

LTC3862HFE-1#PBF from Analog Devices (formerly Linear Technology) is a two-phase, constant-frequency, peak current mode boost/SEPIC DC/DC controller driving N-channel MOSFETs for high-voltage step-up power conversion. It operates from 8.5V to 36V input, delivers up to 96% duty cycle, supports 75kHz–500kHz adjustable switching frequency, and features dual 10V gate drivers with internal 10V/3.8V LDOs - used in automotive 48V-to-72V telecom boost supplies.

For engineers reviewing the LTC3862HFE-1#PBF datasheet, LTC3862HFE-1#PBF pinout, LTC3862HFE-1#PBF application, or LTC3862HFE-1#PBF equivalent, key selection criteria include its H-grade (–40°C to +150°C) junction temperature rating, phase-programmable multi-phase synchronization via SYNC/CLKOUT/PHASEMODE, precision ±1% reference, and 24-lead TSSOP thermal performance (θ_JA = 38°C/W).

Technical Context

The LTC3862HFE-1#PBF implements fixed-frequency, peak-current-mode control with two independent channels operating 180° out of phase to reduce input/output ripple. Its error amplifier compares FB voltage against a 1.223V internal reference, modulating ITH to set peak inductor current; slope compensation gain is programmable via SLOPE pin.

Phase alignment is controlled by PHASEMODE (0V/float/3.8V), enabling 2-, 3-, 4-, 6-, or 12-phase operation when cascaded. The internal PLL synchronizes switching to external clocks (50kHz–650kHz) via SYNC, while DMAX pin sets max duty cycle (75%/84%/96%) with sub-1% precision derived from a 12× internal clock.

Key Specifications

Pinout & Package

Package: 24-lead plastic TSSOP (FE24), 0.65mm lead pitch, exposed PGND pad (Pin 25) - thermally enhanced for high-power density layouts with θ_JA = 38°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3862IFE-1#PBF, the LTC3862HFE-1#PBF extends safe operating temperature by 25°C - critical for engine bay integration - while LTC3862HUH-1#PBF trades TSSOP's mechanical robustness for superior thermal metrics in compact layouts.

Availability

LTC3862HFE-1#PBF is available at Aetrix Electronics and suitable for automotive power conversion, industrial telecom supplies, and aerospace DC/DC modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC3862HFE-1#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 acquired Linear Technology in 2017 and maintains its high-performance analog IC portfolio, emphasizing precision power management, signal conditioning, and RF solutions for demanding applications.

The LTC3862 family is designed specifically for high-efficiency, multi-phase boost and SEPIC DC/DC conversion in automotive, industrial, and telecom systems where wide VIN range, precise current mode control, and extended temperature operation are essential.

FAQ

What is the maximum junction temperature rating for the LTC3862HFE-1#PBF?

The LTC3862HFE-1#PBF is rated for operation from –40°C to +150°C junction temperature (H-grade). This specification is guaranteed across the full range, with thermal protection engaging above 150°C to prevent permanent damage. The exposed PGND pad must be soldered to the PCB ground plane to achieve the specified θ_JA = 38°C/W and sustain continuous operation at rated load.

How does the DMAX pin affect duty cycle limiting in the LTC3862HFE-1#PBF?

The DMAX pin on the LTC3862HFE-1#PBF sets the maximum allowable duty cycle: grounding it yields 96%, leaving it floating gives 84%, and connecting it to 3V8 results in 75%. This limit is derived from a precise 12× internal clock, ensuring sub-1% accuracy. It prevents transformer saturation and overvoltage during light-load or transient conditions without requiring external timing components.

Can the LTC3862HFE-1#PBF synchronize to an external clock, and what is its valid frequency range?

Yes, the LTC3862HFE-1#PBF accepts external synchronization via the SYNC pin across 50kHz to 650kHz. The internal PLL locks to the rising edge of the SYNC signal, aligning GATE1's edge precisely. Input thresholds are 1.5V (rising) and 0.9V (falling); the SYNC pin has a 50kΩ internal pull-down, supporting direct connection to CMOS or LVDS clock sources without level-shifting.

What is the purpose of the SLOPE pin on the LTC3862HFE-1#PBF, and how does it impact stability?

The SLOPE pin on the LTC3862HFE-1#PBF programs the gain of internal ramp compensation: floating sets 1.00×, connecting to 3V8 increases it by 66%, and grounding reduces it by 37.5%. This adjustment stabilizes the current-mode loop across varying duty cycles and inductor values - especially critical in high-step-up boost converters where subharmonic oscillation risk is elevated.

Does the LTC3862HFE-1#PBF support multi-phase operation beyond two phases, and how is it configured?

Yes, the LTC3862HFE-1#PBF supports 2-, 3-, 4-, 6-, or 12-phase operation using SYNC, CLKOUT, and PHASEMODE pins. Cascading multiple LTC3862HFE-1#PBF units requires connecting CLKOUT of one to SYNC of the next, with PHASEMODE set to 0V/float/3V8 to select 180°/180°/120° inter-channel offsets. All FB and ITH pins are paralleled; INTVCC pins must remain isolated to avoid thermal imbalance.