Analog Devices Inc. LTC2928IUHF#TRPBF

Overview

LTC2928IUHF#TRPBF from Analog Devices (formerly Linear Technology) is a four-channel cascadable power supply sequencer and high-accuracy supervisor IC. It performs staged enable/disable sequencing of up to four supplies per device, monitors undervoltage (±1.5% accuracy) and overvoltage conditions, and generates µP reset signals. Used in telecom infrastructure for controlled ramp-up/ramp-down of I/O and core voltage rails.

For engineers reviewing the LTC2928IUHF#TRPBF datasheet, LTC2928IUHF#TRPBF pinout, LTC2928IUHF#TRPBF application, or LTC2928IUHF#TRPBF equivalent, key selection criteria include cascading capability for >4-rail systems, 38-lead QFN package with exposed pad, ±1.5% monitor accuracy, charge-pumped EN outputs (VCC + 5.5V), and fault-diagnostic reporting via CMP/FLT pins.

Technical Context

The LTC2928IUHF#TRPBF implements independent time-position control per channel using external RT resistors, enabling configurable sequencing order and delay between enable edges. Its internal charge pump drives EN1–EN4 to VCC + 5.5V, supporting direct gate control of N-channel MOSFETs without level-shifting circuitry.

Supervision uses precision comparators with programmable thresholds (via SQT1/SQT2 and VSEL), 225µs glitch immunity on UV/OV detection, and integrated timers (RTMR, PTMR, STMR) set by external capacitors. Fault management includes latchable CMP outputs, system-wide shutdown on any internal/external fault, and diagnostic reporting via FLT/CMP states.

Key Specifications

Pinout & Package

38-lead plastic QFN (5mm × 7mm) with exposed thermal pad (pin 39, optional GND connection). Pin functions validated per Linear Technology LTC2928 datasheet Rev. FA.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power supply sequencing and supervision applications.

Compared with LTC2927CUHF#TRPBF and TPS652860RHBR, the LTC2928IUHF#TRPBF provides unmatched configurability for arbitrary rail counts and voltages, supports high-voltage inputs up to 16.5V, and delivers diagnostic visibility via latched comparator outputs - making it optimal for complex, field-upgradable telecom and industrial systems.

Availability

LTC2928IUHF#TRPBF is available at Aetrix Electronics and suitable for telecom infrastructure, FPGA/ASIC power management, and industrial PLC applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for LTC2928IUHF#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 full product support, documentation, and manufacturing continuity for the LTC portfolio.

The LTC2928 series was designed specifically for hardware-based, software-free power sequencing in high-reliability systems where deterministic timing, fault diagnostics, and multi-rail scalability are critical - especially in network infrastructure and industrial control.

FAQ

What is the maximum number of power supplies that can be sequenced using LTC2928IUHF#TRPBF?

The LTC2928IUHF#TRPBF supports unlimited power supply sequencing through its cascading architecture. Each device controls up to four supplies, and multiple LTC2928IUHF#TRPBF units connect via the CAS pin to extend sequencing capacity. The cascade protocol ensures synchronized timing across all devices without software intervention or additional timing components.

Can LTC2928IUHF#TRPBF monitor negative voltage rails?

Yes, the LTC2928IUHF#TRPBF can monitor one negative supply on the V1 input when the VSEL pin is tied to VCC. In this configuration, V1 references the buffered REF output (1.19V typical) instead of ground, enabling adjustable negative rail supervision. V2–V4 remain dedicated to positive rail monitoring, supporting mixed positive/negative systems common in analog signal chains.

How does the charge pump in LTC2928IUHF#TRPBF enable direct N-channel MOSFET control?

The LTC2928IUHF#TRPBF integrates an internal charge pump that elevates EN1–EN4 outputs to VCC + 5.5V (typical), sufficient to fully enhance standard N-channel MOSFETs used as high-side pass elements. This eliminates external gate drivers or level shifters, reduces component count, and ensures robust turn-on even when VCC is as low as 2.9V - a key advantage over open-drain or push-pull alternatives.

What fault conditions trigger FLT assertion in LTC2928IUHF#TRPBF?

The FLT pin of LTC2928IUHF#TRPBF pulls low on internal faults (e.g., UV/OV violation on any monitored rail, timer timeout, or command fault during sequencing) and external faults (e.g., OV pin pulled low or dedicated fault signal applied to FLT). All EN outputs are immediately disabled upon FLT assertion, and fault source is diagnosable via latched CMP1–CMP4 states, enabling rapid system-level debugging.

Is the exposed thermal pad on the LTC2928IUHF#TRPBF QFN package required to be connected to ground?

No, the exposed thermal pad (pin 39) on the LTC2928IUHF#TRPBF QFN package is optional for grounding. When connected to PCB GND, it improves thermal performance (θJA = 34°C/W); when left floating, thermal resistance increases but remains within specification for typical industrial loads. Layout guidelines recommend soldering the pad with thermal vias for high-power or high-ambient applications.