Analog Devices Inc. LTC3633AEFE-3#TRPBF

Overview

LTC3633AEFE-3#TRPBF from Analog Devices (formerly Linear Technology) is a dual-channel monolithic synchronous step-down regulator delivering 3A per channel across a 3.6V–20V input range, with output voltage sense range of 1.5V–12V and internal 0.6V reference for precision regulation. It supports phase-shifted operation (0°/180°), external frequency synchronization, and Burst Mode® for high efficiency in battery-powered instrumentation.

For engineers reviewing the LTC3633AEFE-3#TRPBF datasheet, LTC3633AEFE-3#TRPBF pinout, LTC3633AEFE-3#TRPBF application, or LTC3633AEFE-3#TRPBF equivalent, key selection criteria include its 1.5V–12V VON sense range (distinguishing it from LTC3633A-2), 28-lead TSSOP package with exposed PGND pad, dual-channel current-mode control, and integrated overvoltage/overtemperature protection.

Technical Context

The LTC3633AEFE-3#TRPBF implements a controlled on-time, current-mode architecture with an internal phase-locked loop that locks switching frequency to either an internal oscillator (programmable via RT resistor from 500kHz–4MHz) or an external clock applied to MODE/SYNC. Its dual channels operate independently with separate PVIN inputs, enabling split-rail or isolated supply configurations.

Each channel features independent RUN enable, PGOOD status, TRACKSS soft-start/tracking, ITH compensation, and VON-based on-time control-where VON1/VON2 accept 1.5V–12V inputs to maintain constant frequency across wide output voltage ranges. The device integrates top/bottom MOSFETs with 130mΩ/65mΩ R_DS(ON), supports low-duty-cycle operation down to 5% at 2.25MHz, and delivers up to 95% efficiency at full load.

Key Specifications

Pinout & Package

Package: 28-lead plastic TSSOP with exposed PGND pad (pin 29), rated for –40°C to 125°C junction temperature (θ_JA = 25°C/W). Exposed pad must be soldered to PCB for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3633AEUFD-3#TRPBF, the LTC3633AEFE-3#TRPBF offers identical regulation performance in a through-hole-compatible TSSOP package optimized for manual assembly and thermal reliability at lower cost; versus TPS543B20RTWR, it provides native dual-channel coordination without inter-device synchronization complexity.

Availability

LTC3633AEFE-3#TRPBF is available at Aetrix Electronics and suitable for point-of-load power supplies, battery-powered instrumentation, and industrial control modules requiring stable component supply, long-term lifecycle support, and guaranteed -40°C to 125°C operation.

Supply support for LTC3633AEFE-3#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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving aerospace, industrial, automotive, and communications markets.

The LTC3633A family was designed for high-efficiency, dual-channel DC/DC conversion in space- and thermally-constrained systems where phase control, wide input range, and robust protection are critical-targeting FPGA, ASIC, and microprocessor power delivery.

FAQ

What is the VON sense range for LTC3633AEFE-3#TRPBF, and why does it matter?

The LTC3633AEFE-3#TRPBF has a VON sense range of 1.5V to 12V, distinguishing it from the LTC3633A-2 variant (0.6V–6V). This range defines the output voltages over which the controlled-on-time architecture maintains stable, constant-frequency operation. Using outputs outside this range may cause frequency deviation or instability. Designers must ensure their target VOUT falls within 1.5V–12V when selecting LTC3633AEFE-3#TRPBF.

How does the PHMODE pin affect operation of LTC3633AEFE-3#TRPBF?

The PHMODE pin on LTC3633AEFE-3#TRPBF selects channel phasing: grounding it forces both channels to switch in phase (0°), while tying it to INTVCC configures 180° out-of-phase operation. Out-of-phase switching reduces input and output capacitor RMS current by up to 70%, lowering thermal stress and enabling smaller bulk capacitance-critical for compact, high-density designs.

Can LTC3633AEFE-3#TRPBF synchronize to an external clock, and how is it configured?

Yes, LTC3633AEFE-3#TRPBF can synchronize to an external clock via the MODE/SYNC pin. Applying a clean CMOS-level clock signal (with 50% duty cycle and rise/fall times <10ns) to this pin engages the internal PLL, locking the switching edges to the external source. When synchronized, the device automatically enters forced continuous mode-Burst Mode® is disabled to ensure deterministic timing alignment.

What thermal considerations apply to the TSSOP package of LTC3633AEFE-3#TRPBF?

The LTC3633AEFE-3#TRPBF uses a 28-lead TSSOP with exposed PGND pad (pin 29), achieving θ_JA = 25°C/W with proper PCB copper area. To meet the 125°C max junction temperature, designers must solder the exposed pad to a minimum 200mm² thermal pad connected to inner-layer ground planes. Without adequate thermal relief, power dissipation above ~1.8W risks thermal shutdown under full 3A load at high ambient temperatures.

Does LTC3633AEFE-3#TRPBF support output voltage tracking, and how is it implemented?

Yes, LTC3633AEFE-3#TRPBF supports output voltage tracking via the TRACKSS1 and TRACKSS2 pins. Applying a ramp voltage (e.g., from an RC network) below 0.6V to these pins causes the error amplifier to servo VFB to match the TRACKSS voltage-enabling precise sequencing of multiple rails. An internal 1.4µA pull-up current allows simple soft-start by connecting a capacitor from TRACKSS to SGND, generating a linear voltage ramp.