Analog Devices Inc. LTC7851EUHH#TRPBF

Overview

LTC7851EUHH#TRPBF from Analog Devices is a quad-output, multiphase synchronous step-down voltage mode DC/DC controller supporting up to 4 independent or paralleled phases, with 0.6V–(VCC–0.5V) output range, ±0.75% reference accuracy, and 250kHz–2.25MHz programmable switching frequency. It enables high-current FPGA/DSP supplies using DrMOS, power blocks, or external gate drivers.

For engineers reviewing the LTC7851EUHH#TRPBF datasheet, LTC7851EUHH#TRPBF pinout, LTC7851EUHH#TRPBF application, or LTC7851EUHH#TRPBF equivalent, key selection criteria include phase-interleaved current sharing accuracy, lossless DCR or precision RSENSE sensing capability, remote differential voltage sensing architecture, and support for daisy-chained multiphase scaling beyond four phases.

Technical Context

The LTC7851EUHH#TRPBF implements a constant-frequency voltage-mode control architecture with four independent error amplifiers (COMP1–COMP4), each driving its own PWM output. Its internal current sharing loop uses IAVG bus integration and master/slave configuration to maintain ≤±5% inter-phase current imbalance under dynamic load steps.

It supports three current sensing methods: inductor DCR (lossless), discrete sense resistors, or integrated current sense signals from DrMOS devices - with dedicated ISNSP/ISNSN inputs per channel and configurable ILIM threshold pins. The device features quad differential VSNSP/VSNSN sense amplifiers with 600mV nominal output and 40MHz unity-gain bandwidth for precise remote sensing.

Key Specifications

Pinout & Package

58-lead plastic QFN (5mm × 9mm, 0.4mm pitch); exposed thermal pad (Pin 59) is SGND and must be soldered to PCB ground plane for rated thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multiphase step-down controller applications.

Compared with LTC7851IUHH#TRPBF, the LTC7851EUHH#TRPBF offers identical functionality at lower cost but with design-assured (not tested) specs above 85°C; compared with LTC7851EUHH-1#TRPBF, it provides higher gain for precision external sensing but requires tighter layout control for noise rejection.

Availability

LTC7851EUHH#TRPBF is available at Aetrix Electronics and suitable for high-current FPGA power supplies, telecom baseband processor rails, and data center ASIC VRMs requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LTC7851EUHH#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. is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision instrumentation, power management, and signal integrity applications.

The LTC7851 product line delivers quad-output, multiphase voltage mode controllers engineered for high-current, low-voltage distributed power systems in computing, networking, and communications infrastructure.

FAQ

What is the maximum number of phases supported by the LTC7851EUHH#TRPBF?

The LTC7851EUHH#TRPBF natively supports up to four phases per IC. Multiple LTC7851EUHH#TRPBF devices can be daisy-chained via CLKOUT/CLKIN to scale to eight or more phases. Each IC contributes four synchronized PWM outputs, and phase alignment (e.g., 0°/90°/180°/270°) is maintained through internal PLL locking to the master clock source.

Can the LTC7851EUHH#TRPBF operate with only two active outputs while disabling the other two?

Yes, the LTC7851EUHH#TRPBF supports independent channel control. To disable Channels 3 and 4, tie RUN3 and RUN4 to SGND (below 2V). The corresponding COMP3/COMP4 outputs will be actively pulled low, PWM3/PWM4 go high-impedance, and PGOOD3/PGOOD4 remain inactive. Channels 1 and 2 continue full regulation with no impact on performance.

How does the LTC7851EUHH#TRPBF achieve accurate current sharing between phases?

The LTC7851EUHH#TRPBF achieves accurate current sharing via its dedicated IAVG bus: the master channel's IAVG pin sources a voltage proportional to its average inductor current; slave channels integrate the difference between their sensed current and the master's IAVG voltage, then sum this correction with their COMP signal to adjust duty cycle-ensuring ≤±5% current mismatch under steady-state and transient conditions.

What is the purpose of the VSNSP and VSNSN pins on the LTC7851EUHH#TRPBF?

The VSNSP and VSNSN pins on the LTC7851EUHH#TRPBF form a differential pair that connects to the output load's feedback divider midpoint (VSNSP) and remote load ground (VSNSN). This configuration rejects PCB ground bounce and common-mode noise, enabling precise remote voltage sensing. The resulting VSNSOUT signal feeds the FB pin, ensuring regulation accuracy is maintained at the point of load-not at the regulator output terminals.

Is the LTC7851EUHH#TRPBF compatible with both DrMOS and discrete MOSFET power stages?

Yes, the LTC7851EUHH#TRPBF is fully compatible with DrMOS, power blocks, and discrete N-channel MOSFETs driven by external gate drivers. Its PWM outputs are three-state compatible and designed for single-wire interface. For DrMOS, use the standard LTC7851 variant (20V/V current sense gain); for discrete stages with RSENSE or DCR, the same LTC7851EUHH#TRPBF applies without modification.