Analog Devices Inc. LTC3736EGN-2#TRPBF

Overview

LTC3736EGN-2#TRPBF from Analog Devices (formerly Linear Technology) is a dual 2-phase synchronous step-down controller driving external complementary MOSFETs without current-sense resistors. It delivers precise output tracking, 0.6V ±1% reference, 300–750kHz programmable switching frequency, and 100% duty cycle for low-dropout operation in battery-powered systems.

For engineers reviewing the LTC3736EGN-2#TRPBF datasheet, LTC3736EGN-2#TRPBF pinout, LTC3736EGN-2#TRPBF application, or LTC3736EGN-2#TRPBF equivalent, key selection criteria include out-of-phase dual-phase operation to reduce input RMS current, V_DS-based current sensing, tracking startup capability, pulse-skipping vs forced continuous mode control via SYNC/FCB, and thermal performance in the 24-lead SSOP package.

Technical Context

The LTC3736EGN-2#TRPBF implements two independent constant-frequency current-mode controllers operating 180° out-of-phase to minimize input capacitor RMS current and EMI. Each channel uses MOSFET V_DS sensing for peak current detection, eliminating sense resistors while maintaining accuracy across duty cycles.

Its PLL architecture enables synchronization from 250kHz to 850kHz via SYNC/FCB, with PLLLPF pin configuring loop filter or frequency selection. Tracking functionality ties VOUT2 startup to VOUT1 via resistor divider on TRACK pin, ensuring monotonic sequencing without external circuitry.

Key Specifications

Pinout & Package

The LTC3736EGN-2#TRPBF is housed in a 24-lead narrow SSOP package (GN), thermally enhanced with exposed PGND pads at pins 12, 16, 20, and 25. Pin pitch is 0.65mm; body size is 7.5mm × 4.4mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ISL95836IRZ-T and MP2964GQ-Z, the LTC3736EGN-2#TRPBF uniquely combines V_DS-based current sensing, analog tracking, 100% duty cycle, and sub-10μA shutdown - making it optimal for high-efficiency, battery-constrained, dual-rail applications requiring precise sequencing and minimal component count.

Availability

LTC3736EGN-2#TRPBF is available at Aetrix Electronics and suitable for notebook computers, portable instrumentation, distributed power systems, and battery-powered industrial handhelds requiring stable component supply and long-term obsolescence management.

Supply support for LTC3736EGN-2#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 acquired Linear Technology in 2017 and maintains its precision power management portfolio. Linear pioneered high-performance analog ICs for demanding power applications.

The LTC3736EGN-2#TRPBF belongs to Linear's No RSENSE™ synchronous controller family, designed specifically for high-efficiency, low-noise, multi-rail DC/DC conversion in space- and power-constrained portable and industrial systems.

FAQ

What is the function of the TRACK pin on the LTC3736EGN-2#TRPBF?

The TRACK pin on the LTC3736EGN-2#TRPBF enables analog output voltage tracking during startup. When the TRACK voltage is below 0.6V, the controller regulates VFB2 to match the TRACK voltage instead of the internal 0.6V reference. This allows VOUT2 to ramp proportionally with VOUT1 using a simple resistor divider from VOUT1 to TRACK - ensuring monotonic, coordinated sequencing without external ICs or firmware. The LTC3736EGN-2#TRPBF implements this behavior natively in its error amplifier path.

How does the LTC3736EGN-2#TRPBF achieve current sensing without a sense resistor?

The LTC3736EGN-2#TRPBF senses current by measuring the voltage drop (V_DS) across the external P-channel MOSFET during its on-time, using SENSE+ and SW pins as differential inputs to an internal current comparator. This eliminates power loss and thermal drift associated with discrete sense resistors. The maximum allowable ΔV_SENSE is selectable via IPRG1/IPRG2 pins (167/240/345mV), and slope compensation automatically adjusts for duty cycles above 20%. The LTC3736EGN-2#TRPBF thus achieves accurate, efficient current limiting without added components.

Can the LTC3736EGN-2#TRPBF operate with input voltages below 3V?

Yes, the LTC3736EGN-2#TRPBF supports an input voltage range of 2.75V to 9.8V, making it suitable for single-cell Li-ion (2.7–4.2V) and deeply discharged multi-cell batteries. Its undervoltage lockout activates at 2.25V (rising) and 1.95V (falling), ensuring safe operation down to near-end-of-discharge. Additionally, 100% duty cycle capability allows regulation even when VIN approaches VOUT - critical for maximizing runtime. The LTC3736EGN-2#TRPBF maintains full functionality including tracking and PGOOD monitoring across this entire range.

What is the purpose of the SYNC/FCB pin on the LTC3736EGN-2#TRPBF?

The SYNC/FCB pin on the LTC3736EGN-2#TRPBF serves three distinct functions: (1) auxiliary winding feedback input for secondary-side regulation, (2) external clock synchronization input for the internal PLL (250–850kHz), and (3) mode selection for light-load operation - tying to VIN enables pulse-skipping, while grounding selects forced continuous conduction. These functions are mutually exclusive and determined by voltage level or signal presence. The LTC3736EGN-2#TRPBF integrates all three into one pin to minimize footprint while preserving flexibility across diverse power architectures.

Does the LTC3736EGN-2#TRPBF support phase interleaving, and how does it improve performance?

Yes, the LTC3736EGN-2#TRPBF inherently operates its two controllers 180° out-of-phase, achieving true 2-phase interleaving. This interleaving reduces input capacitor RMS current by up to 50% compared to in-phase dual controllers - lowering required capacitance, EMI, and power loss in input paths (including batteries and PCB traces). In a typical 2A-per-rail application, interleaving cuts input RMS current from 1.79A to 0.91A, reducing I²R losses by 3.86×. The LTC3736EGN-2#TRPBF delivers this benefit without external timing components or configuration.