Analog Devices Inc. LTC1439CGW#PBF

Overview

LTC1439CGW#PBF from Analog Devices (formerly Linear Technology) is a dual, synchronous step-down switching regulator controller driving external N-channel MOSFETs in a phase-lockable fixed-frequency architecture. It delivers two regulated outputs (e.g., 5V/3.3V), supports Adaptive Power™ mode for ultrahigh efficiency down to ~1% load, and integrates a 0.5A auxiliary linear regulator for low-noise VPP or audio supply - used in portable instrumentation and battery-powered computing systems.

For engineers reviewing the LTC1439CGW#PBF datasheet, LTC1439CGW#PBF pinout, LTC1439CGW#PBF application, or LTC1439CGW#PBF equivalent, key selection factors include its 36-lead SSOP-GW package, programmable 112–138 kHz oscillator (PLL-synchronizable up to 240 kHz), dual current-mode control with remote sense, and logic-controlled micropower shutdown (I_Q < 30 µA).

Technical Context

The LTC1439CGW#PBF implements a constant-frequency, current-mode dual buck controller with independent error amplifiers, adaptive gate drive (TGL/TGS/BG pins), and secondary feedback (SFB1) for forced continuous operation. Its Adaptive Power™ architecture dynamically switches between large and small top-side MOSFET drivers to maintain fixed frequency and high efficiency across 1%–100% load range.

It features integrated functions including a 0.5A PNP-based auxiliary linear regulator (AUXFB/AUXDR/AUXON), low-battery comparator (LBI/LBO), power-on reset timer (POR2, 65536-cycle delay), and PLL synchronization via PLLIN/PLL LPF - all operating from a wide 3.5V–30V input with 36V absolute max.

Key Specifications

Pinout & Package

Package: 36-lead plastic SSOP (GW suffix), 0.025" pitch, thermal resistance θ_JA = 85°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC1439CGW#PBF, LTC3723EGN#PBF offers higher per-channel current but sacrifices dual-rail coordination and auxiliary functionality, while MP2918GL-Z reduces footprint and cost at the expense of critical features like SFB1 enforcement and integrated VPP generation - making LTC1439CGW#PBF uniquely suited for precision, low-noise, multi-rail portable power.

Availability

LTC1439CGW#PBF is available at Aetrix Electronics and suitable for portable instrumentation, battery-powered computing, and industrial test equipment requiring stable component supply with guaranteed long-term availability and full temperature-grade support.

Supply support for LTC1439CGW#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; Linear pioneered high-performance power management ICs with emphasis on precision, efficiency, and robustness in demanding environments.

The LTC1439CGW#PBF belongs to Linear's legacy high-efficiency dual buck controller family, designed specifically for portable and battery-operated systems requiring coordinated multi-rail regulation, low-light-load efficiency, and integrated auxiliary functions.

FAQ

What is the primary function of the SFB1 pin on the LTC1439CGW#PBF?

The SFB1 pin on the LTC1439CGW#PBF is a secondary winding feedback input that forces continuous conduction mode on Channel 1 regardless of load. When pulled below 1.19V, it overrides Adaptive Power™ behavior to ensure regulation in transformer-coupled or flyback-derived topologies - a critical feature absent in most dual controllers. This guarantees stable operation even under very light or no-load conditions on the main output.

How does Adaptive Power™ mode improve efficiency at light loads in the LTC1439CGW#PBF?

Adaptive Power™ mode in the LTC1439CGW#PBF improves light-load efficiency by dynamically routing gate drive from the high-current TGL1/TGL2 outputs to the low-current TGS1/TGS2 outputs, enabling use of a smaller MOSFET and Schottky diode. This avoids large gate charge losses inherent to full-size MOSFETs, sustaining fixed-frequency operation down to ~1% of rated load - an order-of-magnitude improvement over standard burst mode.

Can the LTC1439CGW#PBF generate a 12V auxiliary supply, and how is it configured?

Yes, the LTC1439CGW#PBF can generate a regulated 12V auxiliary supply using its integrated linear regulator block. When AUXDR voltage exceeds 9.5V, the internal 12V resistive divider connects automatically to AUXFB, enabling 12V output with an external PNP pass transistor. Configuration requires pulling AUXON high, connecting AUXFB to the PNP emitter, and tying AUXDR to the PNP base - no external feedback resistors needed for 12V.

What is the purpose of the POR2 pin on the LTC1439CGW#PBF, and how is its timing determined?

The POR2 pin on the LTC1439CGW#PBF is an open-drain power-on reset output that asserts when Channel 2's output falls >7.5% below regulation and releases after exactly 65536 oscillator cycles once VOUT2 recovers within 5% of target. Its timing is cycle-accurate and temperature-stable - approximately 300 ms at 125 kHz - providing deterministic system reset without external RC networks or supervisors.

Does the LTC1439CGW#PBF support synchronization between multiple units, and what pins are involved?

Yes, the LTC1439CGW#PBF supports synchronization via its integrated Phase-Locked Loop. The PLLIN pin accepts an external clock signal, and the PLL LPF pin serves as both phase detector output and oscillator control input (0–2.4V range). When locked, the controller aligns top-MOSFET turn-on edges to the rising edge of the external clock - enabling coherent multi-phase operation across multiple LTC1439CGW#PBF units without timing skew.