Analog Devices Inc. LTC1629CG-PG#TRPBF

Overview

LTC1629CG-PG#TRPBF from Analog Devices (formerly Linear Technology) is a dual-phase, synchronous step-down switching regulator controller driving external N-channel MOSFETs in a phase-lockable, current-mode architecture. It delivers up to 40A output with ±1% voltage accuracy, 150–300kHz per-phase switching (1.8MHz effective), and true remote differential sensing for high-current server and desktop power rails.

For engineers reviewing the LTC1629CG-PG#TRPBF datasheet, LTC1629CG-PG#TRPBF pinout, LTC1629CG-PG#TRPBF application, or LTC1629CG-PG#TRPBF equivalent, key selection criteria include its PolyPhase™ phase-locked synchronization capability, PGOOD output monitoring, OPTI-LOOP™ compensation for wide ESR/COUT tolerance, and 28-lead SSOP package with verified thermal performance up to 85°C ambient.

Technical Context

The LTC1629CG-PG#TRPBF implements a fixed-frequency, current-mode control loop with dual independent channels operating out-of-phase to reduce RMS input/output ripple. Its internal 5V LDO (INTVCC) powers gate drivers, while EXTVCC switchover enables high-efficiency self-biasing at ≥4.7V.

It integrates a precision differential amplifier (ADA = 0.995–1.005 V/V, CMRR = 46–55 dB) for true remote sensing and a dedicated PGOOD open-drain output that asserts low when EAIN deviates >±7.5% from 0.8V reference - a feature exclusive to the -PG variant replacing AMPMD.

Key Specifications

Pinout & Package

Package: 28-lead plastic SSOP (G package), 0.635 mm pitch, JEDEC MS-012AC compliant, θJA = 95°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC3838EGN#TRPBF and MP8765GL-Z, the LTC1629CG-PG#TRPBF uniquely supports scalable PolyPhase™ expansion, true differential remote sensing, and PGOOD monitoring - making it the only option among the three qualified for high-reliability, high-current server and workstation VRMs requiring synchronized multi-phase operation.

Availability

LTC1629CG-PG#TRPBF is available at Aetrix Electronics and suitable for desktop CPU core power, internet server VRMs, large memory arrays, and DC power distribution systems requiring stable component supply across extended product lifecycles.

Supply support for LTC1629CG-PG#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, formed through the acquisition of Linear Technology in 2017.

The LTC1629CG-PG#TRPBF belongs to ADI's high-current PolyPhase™ controller family, designed specifically for multi-phase, high-efficiency DC/DC conversion in computing, datacenter, and industrial power systems demanding precision regulation and scalable phase synchronization.

FAQ

What is the maximum output current supported by the LTC1629CG-PG#TRPBF in a dual-phase configuration?

The LTC1629CG-PG#TRPBF itself does not deliver current - it controls external N-channel MOSFETs. In a properly designed dual-phase layout with appropriate MOSFETs (e.g., IRF7809/IRF7811), inductors, and thermal management, the LTC1629CG-PG#TRPBF enables up to 40A continuous output, as validated in the datasheet's Figure 1 reference design delivering 1.6V/40A. Peak current capability depends on RSENSE value, MOSFET RDS(on), and thermal derating.

Does the LTC1629CG-PG#TRPBF support synchronization with external clock sources?

Yes, the LTC1629CG-PG#TRPBF supports external synchronization via the PLLIN pin (Pin 6), which accepts a TTL/CMOS clock signal. The internal phase-locked loop aligns the rising edge of TG1 to the rising edge of the external clock. This allows precise timing coordination across multiple LTC1629CG-PG#TRPBF controllers or with system clocks in tightly synchronized power architectures.

How does the PGOOD function work on the LTC1629CG-PG#TRPBF, and what is its trip threshold?

The PGOOD pin (Pin 15) on the LTC1629CG-PG#TRPBF is an open-drain output that pulls low when the voltage at EAIN deviates more than ±7.5% from the 0.800 V internal reference - corresponding to ±60 mV absolute error. It releases (high-impedance) within 10 µs once regulation is restored. An external pull-up resistor (to ≤7 V) is required; typical values range from 10 kΩ to 100 kΩ depending on sink current and noise immunity needs.

Can the LTC1629CG-PG#TRPBF operate in dropout mode, and what is its minimum duty cycle?

Yes, the LTC1629CG-PG#TRPBF supports very low dropout operation with a maximum duty cycle of 99.5%, enabling regulation even when VIN approaches VOUT. During dropout, an internal circuit forces the top MOSFET off for ~400 ns every 10th cycle to recharge the bootstrap capacitor - maintaining gate drive integrity without requiring external circuitry or sacrificing regulation accuracy.

What is the purpose of the VDIFFOUT pin on the LTC1629CG-PG#TRPBF, and how is it used in the feedback network?

The VDIFFOUT pin (Pin 10) outputs the amplified difference between VOS+ and VOS−, providing true remote sensing of the regulated output. It drives an external resistive divider (e.g., R1/R2) that sets the final output voltage. For example, with R1 = 16.2 kΩ and R2 = 1.62 kΩ, VDIFFOUT = 1.8 V yields VOUT = 1.8 V × (1 + R1/R2) = 1.8 V × 11 = 19.8 V - though typical use targets 1.2–3.3 V rails. This architecture rejects voltage drop across PCB traces between the IC and load.