Analog Devices Inc. LTC3727EUH-1#PBF

Overview

LTC3727EUH-1#PBF from Analog Devices (formerly Linear Technology) is a dual-phase, synchronous step-down switching regulator controller driving two independent N-channel MOSFET stages in 180° out-of-phase operation. It supports 4V–36V input, 0.8V–14V output, ±1% voltage accuracy, and phase-lockable 250kHz–550kHz fixed-frequency operation - enabling high-efficiency dual-rail power supplies for telecom base stations and automotive infotainment systems.

For engineers reviewing the LTC3727EUH-1#PBF datasheet, LTC3727EUH-1#PBF pinout, LTC3727EUH-1#PBF application, or LTC3727EUH-1#PBF equivalent, key selection criteria include out-of-phase current ripple reduction, OPTI-LOOP® compensation for wide-output-capacitance stability, dual-channel independent soft-start via RUN/SS pins, and integrated 3.3V linear regulator with 10mA load capability.

Technical Context

The LTC3727EUH-1#PBF implements constant-frequency current-mode control with dual independent error amplifiers (ITH1/ITH2), each feeding a peak-current comparator referenced to a precision 0.8V feedback node (VOSENSE1/VOSENSE2). Its 180° interleaved phase operation reduces input RMS current by up to 39% versus in-phase dual controllers, directly lowering EMI and input capacitor stress.

It integrates a phase-locked loop (PLLIN/PLLFLTR) for external synchronization, FCB pin-controlled mode selection (Burst Mode®, forced continuous, or constant-frequency), and dedicated protection circuits including output overvoltage lockout (0.84–0.88V threshold), latched short-circuit shutdown (LTC3727 variant only), and dropout detection enabling 99.4% duty cycle operation.

Key Specifications

Pinout & Package

Package: 32-lead 5mm × 5mm plastic QFN (UH) with exposed thermal pad (Pin 33 = SGND), θJA = 34°C/W - optimized for high-power density and thermal performance in space-constrained industrial and automotive PCBs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-phase synchronous buck controller applications.

Compared with LTC3727EUH-1#PBF, LTC3855IUFD#PBF offers higher phase count but requires external components for dual-rail independence, while MP8772GQ-Z simplifies layout at the expense of ripple reduction, thermal derating margin, and protection granularity.

Availability

LTC3727EUH-1#PBF is available at Aetrix Electronics and suitable for telecom power systems, automotive infotainment modules, and industrial PLC designs requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for LTC3727EUH-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 full product support, documentation, and manufacturing continuity for the LTC® portfolio of high-performance power management ICs.

The LTC3727EUH-1#PBF belongs to Linear's high-efficiency dual-phase controller family, designed specifically for applications demanding reduced input ripple, tight output regulation, and robust fault protection in space- and thermally-constrained environments.

FAQ

What is the maximum duty cycle supported by the LTC3727EUH-1#PBF?

The LTC3727EUH-1#PBF supports a maximum duty cycle of 99.4%, enabling operation in dropout conditions where input voltage approaches output voltage. This is achieved via internal dropout detection that periodically disables the top MOSFET to recharge the bootstrap capacitor. The LTC3727EUH-1#PBF maintains regulation down to VIN ≈ VOUT + 0.2V under typical conditions, making it suitable for automotive cold-crank scenarios.

Does the LTC3727EUH-1#PBF include short-circuit latchoff protection?

No, the LTC3727EUH-1#PBF does not include latched short-circuit shutdown. That feature is exclusive to the base LTC3727 (e.g., LTC3727EG) variant. The LTC3727EUH-1#PBF is the -1 version, which disables the latchoff function per datasheet specification. It retains foldback current limiting and overvoltage protection, but relies on external supervision or system-level fault handling for persistent overcurrent events.

Can the LTC3727EUH-1#PBF drive both controllers synchronously to an external clock?

Yes, the LTC3727EUH-1#PBF supports full external synchronization via the PLLIN pin. When an external clock signal is applied to PLLIN, the internal phase-locked loop aligns the rising edge of TG1 to that signal's rising edge. The PLLFLTR pin serves as both the phase detector output and DC frequency control input, allowing fine-tuning of operating frequency between 220kHz and 580kHz while locked.

What is the purpose of the FCB pin on the LTC3727EUH-1#PBF?

The FCB (Forced Continuous/Burst) pin on the LTC3727EUH-1#PBF selects among three operating modes: pulling FCB below 0.8V forces continuous conduction mode; holding FCB between 0.8V and VINTVCC – 2V enables Burst Mode® for ultralow IQ; applying >6.8V selects constant-frequency operation. This pin also enables secondary-winding regulation in flyback-derived auxiliary supplies - a unique capability not found in most dual controllers.

How does the LTC3727EUH-1#PBF handle thermal management in the UH package?

The LTC3727EUH-1#PBF uses a 5mm × 5mm QFN package (UH) with an exposed thermal pad (Pin 33) that must be soldered to PCB ground. Its thermal resistance is θJA = 34°C/W - significantly lower than the SSOP variant (θJA = 95°C/W). To ensure reliability, designers must use ≥4 thermal vias under the pad connected to an internal ground plane, and maintain ≥4.7μF low-ESR capacitance on INTVCC per Linear's layout guidelines.