Analog Devices Inc. LTC3634IFE#TRPBF

Overview

LTC3634IFE#TRPBF from Analog Devices (formerly Linear Technology) is a dual-channel monolithic synchronous step-down regulator optimized for DDR1/DDR2/DDR3 memory power supplies, delivering ±3A per channel at VDDQ = 1.8V and VTT = 0.9V from a 3.6V–15V input. It integrates VTTR reference buffering (±10mA, ±1.6% accuracy at 0.75V), 180° out-of-phase operation, and programmable 500kHz–4MHz switching frequency - enabling compact, high-efficiency point-of-load designs in server, networking, and FPGA-based systems.

For engineers reviewing the LTC3634IFE#TRPBF datasheet, LTC3634IFE#TRPBF pinout, LTC3634IFE#TRPBF application, or LTC3634IFE#TRPBF equivalent, this page delivers verified technical context, validated pin functions, confirmed DDR-specific timing and regulation behavior, real-world efficiency vs. load curves, and precise alternative selection guidance - all grounded in the official Linear Technology LTC3634 datasheet (3634fc) and package marking data.

Technical Context

The LTC3634IFE#TRPBF implements current-mode control with a unique controlled on-time architecture, enabling stable high-frequency operation (up to 4MHz) even at low VOUT/VIN ratios required for DDR VDDQ (0.6V–3V) and VTT (0.75V typical). Its dual channels operate independently: Channel 1 supports Burst Mode® for light-load efficiency and MODE/SYNC-driven external clock synchronization; Channel 2 runs forced continuous mode and uses VTTR (VDDQIN × 0.5) as its feedback reference.

Phase alignment is hardware-selectable via PHMODE (0V = 90°, INTVCC = 180°), reducing input RMS current and easing input capacitor sizing. Integrated protections include VIN overvoltage lockout (17.5V trip), thermal shutdown, short-circuit limiting (±3.3A to ±5.5A valley current), and open-drain PGOOD status outputs with 15mV hysteresis referenced to either 0.6V (VDDQ) or VTTR (VTT).

Key Specifications

Pinout & Package

Package: 28-lead plastic TSSOP (FE package), 4mm × 5mm footprint, exposed PGND pad (Pin 29) requiring PCB soldering for thermal and electrical integrity. θJA = 25°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS51220RGER and ISL95812IRZ, the LTC3634IFE#TRPBF uniquely combines monolithic ±3A VTT sinking/sourcing, programmable 500kHz–4MHz switching, hardware-selectable 180° interleaving, and an integrated ±1.6%-accurate VTTR buffer - making it the only drop-in solution for space-constrained, high-reliability DDR3 systems requiring TSSOP packaging and thermal derating headroom.

Availability

LTC3634IFE#TRPBF is available at Aetrix Electronics and suitable for DDR memory power supplies, FPGA I/O termination systems, and industrial PLC memory modules requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for LTC3634IFE#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 precision instrumentation, communications, and industrial markets.

The LTC3634 belongs to Linear's DDR-specific power management product line, engineered to replace multi-chip solutions with single-package regulators that meet JEDEC timing, accuracy, and transient response requirements for DDR1–DDR3 memory interfaces.

FAQ

What is the maximum supported input voltage for the LTC3634IFE#TRPBF?

The LTC3634IFE#TRPBF has an absolute maximum VIN rating of 16V, with transient overvoltage lockout activating at 17.5V (rising) and releasing at 16.5V (falling). Continuous operation is specified from 3.6V to 15V, making it compatible with standard 5V and 12V intermediate bus architectures used in DDR memory systems.

Does the LTC3634IFE#TRPBF support DDR4 memory applications?

The LTC3634IFE#TRPBF was designed for DDR1/DDR2/DDR3 compliance and supports VDDQ down to 0.6V and VTTR at VDDQIN × 0.5 - matching DDR3's 0.75V VTT requirement. While it can generate DDR4's 1.2V VDDQ, it lacks native support for DDR4's 0.6V VTT (requiring external scaling) and does not include DDR4-specific timing features like write-leveling support.

How is phase interleaving configured on the LTC3634IFE#TRPBF?

Phase interleaving on the LTC3634IFE#TRPBF is set via the PHMODE pin: grounding PHMODE configures 90° phase shift, while tying PHMODE to INTVCC selects 180° out-of-phase operation. This hardware-selectable feature reduces input RMS current and relaxes input capacitor sizing - critical for high-density DDR power delivery networks.

What is the purpose of the VTTR pin on the LTC3634IFE#TRPBF?

The VTTR pin on the LTC3634IFE#TRPBF provides a buffered, low-noise reference voltage equal to half the VDDQIN input (VDDQIN × 0.5), accurate to ±1.6% at 0.75V. It sources/sinks ±10mA and directly drives DDR memory VREF pins, eliminating the need for an external reference IC and ensuring tight tracking between VDDQ and VTT rails.

Can the LTC3634IFE#TRPBF operate with only one channel enabled?

Yes, the LTC3634IFE#TRPBF supports independent channel control: pulling RUN1 below 1.01V disables Channel 1 (VDDQ) while keeping Channel 2 (VTT) active, and vice versa with RUN2. Both channels can be disabled simultaneously for ultra-low quiescent current (<15µA), enabling flexible power sequencing in multi-rail DDR systems.