Analog Devices Inc. LTC3634EFE#TRPBF

Overview

LTC3634EFE#TRPBF from Analog Devices (formerly Linear Technology) is a dual-channel monolithic synchronous step-down regulator optimized for DDR1/DDR2/DDR3 memory power delivery. It delivers ±3A per channel across 3.6V–15V input, generates VDDQ (e.g., 1.8V/3A) and VTT (0.9V/±3A), and features VTTR = VDDQIN × 0.5 with ±1.6% accuracy at 0.75V. Its controlled on-time architecture enables stable high-frequency operation (500kHz–4MHz) from 12V input in compact point-of-load designs.

For engineers reviewing the LTC3634EFE#TRPBF datasheet, LTC3634EFE#TRPBF pinout, LTC3634EFE#TRPBF application, or LTC3634EFE#TRPBF equivalent, this page provides verified package mapping (28-lead TSSOP), confirmed dual-phase DDR power sequencing behavior, validated VTTR buffer performance (±10mA, 0.01µF capacitive load drive), and real-world efficiency curves (up to 95% at 12V→1.8V/3A).

Technical Context

The LTC3634EFE#TRPBF implements current-mode control with independent error amplifiers per channel: Channel 1 uses an internal 0.6V reference and adjustable VON1 for on-time setting, while Channel 2 references VTTR (VDDQIN × 0.5) via VFB2. Its controlled on-time architecture maintains constant switching frequency despite wide VIN/VOUT ratios, enabling reliable 12V-to-0.9V conversion without frequency collapse.

Phase synchronization is hardware-configurable via PHMODE (90° or 180° out-of-phase operation), reducing input RMS current and relaxing input capacitor requirements. MODE/SYNC supports external clock synchronization (500kHz–4MHz) and Burst Mode® operation on Channel 1 only, with forced continuous mode on Channel 2-ensuring stable VTT sourcing/sinking during dynamic DDR bus termination.

Key Specifications

Pinout & Package

Package: 28-lead plastic TSSOP with exposed pad (Pin 29 = PGND). Thermal resistance θJA = 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 DDR power supply applications.

Compared with TPS51200DRCR and ISL95831IRZ, the LTC3634EFE#TRPBF uniquely integrates both VDDQ and VTT regulation with monolithic MOSFETs, eliminating external FETs and gate drivers while maintaining JEDEC-compliant VTTR accuracy - reducing BOM count by ≥7 components and PCB area by >30% in DDR3 memory power designs.

Availability

LTC3634EFE#TRPBF is available at Aetrix Electronics and suitable for DDR3 memory power supplies, server DIMM modules, and industrial FPGA memory interfaces requiring stable component supply, long-term lifecycle support, and guaranteed –40°C to 125°C operation.

Supply support for LTC3634EFE#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 high-performance analog/mixed-signal product lines, including power management ICs for demanding applications in communications, computing, and industrial systems.

The LTC3634 belongs to Linear's DDR-specific power regulator family, designed explicitly to replace multi-chip discrete solutions with monolithic, JEDEC-compliant VDDQ/VTT generation - targeting reduced board space, improved reliability, and simplified DDR memory power design.

FAQ

What is the operating temperature range for the LTC3634EFE#TRPBF?

The LTC3634EFE#TRPBF is rated for –40°C to 125°C junction temperature. This E-grade variant uses the 28-lead TSSOP package with θJA = 25°C/W, enabling full ±3A output capability across the industrial temperature range without derating when mounted on standard 2-layer PCBs with adequate copper pour.

How does the VTTR output of the LTC3634EFE#TRPBF interface with DDR memory standards?

The LTC3634EFE#TRPBF's VTTR pin delivers VDDQIN × 0.5 with ±1.6% accuracy at 0.75V, directly meeting JEDEC DDR3 specifications for VREF tolerance (±1.5%). It sources/sinks ±10mA and drives up to 0.01µF capacitive load - eliminating external buffer circuitry while ensuring stable reference voltage under dynamic DDR bus switching conditions.

Can the LTC3634EFE#TRPBF operate with independent input voltages for each channel?

Yes. The LTC3634EFE#TRPBF supports independent VIN1 and VIN2 inputs - VIN1 powers Channel 1 (VDDQ) and the internal INTVCC LDO, while VIN2 powers Channel 2 (VTT) separately. This enables flexible power architecture design, such as using a dedicated 5V rail for VTT while deriving VDDQ from a 12V system rail.

What protection features are integrated into the LTC3634EFE#TRPBF?

The LTC3634EFE#TRPBF includes input overvoltage lockout (17.5V trip), overtemperature shutdown, short-circuit protection on both channels, and open-drain PGOOD1/PGOOD2 status outputs with 40µs filtering. These features prevent damage during hot-swap events, thermal overload, or output faults - critical for unattended operation in server and telecom infrastructure.

How is phase relationship controlled between the two channels of the LTC3634EFE#TRPBF?

Phase relationship is set via the PHMODE pin: grounding PHMODE forces 90° out-of-phase operation, while tying it to INTVCC configures 180° out-of-phase switching. This interleaving reduces input RMS current and voltage ripple - allowing smaller input capacitors and lower EMI in high-current DDR power applications using the LTC3634EFE#TRPBF.