Analog Devices Inc. LTC2928CG#PBF

Overview

LTC2928CG#PBF from Analog Devices (formerly Linear Technology) is a four-channel cascadable power supply sequencer and high-accuracy supervisor IC. It provides staged enable control for up to four supplies per device, 1.5% undervoltage monitor accuracy, and configurable sequencing order/timing via external resistors. Used in telecom infrastructure to coordinate startup/shutdown of core and I/O voltage rails.

For engineers reviewing the LTC2928CG#PBF datasheet, LTC2928CG#PBF pinout, LTC2928CG#PBF application, or LTC2928CG#PBF equivalent, key selection criteria include cascading capability for >4-rail systems, charge-pumped EN outputs driving N-channel MOSFETs, fault event reporting with diagnostics, and support for both positive-only and mixed (3× positive + 1× negative) supply monitoring.

Technical Context

The LTC2928CG#PBF implements a state-machine-based sequencing engine with independent RT1–RT4 time-position decoders, enabling precise per-channel enable/disable timing during sequence-up and sequence-down phases. Its internal charge pump generates VCC + 5.5V on EN1–EN4 outputs to drive external N-channel pass FETs without level-shifting circuitry.

Supervision uses precision comparators with 1.5% threshold accuracy across –40°C to 85°C, supporting undervoltage/overvoltage detection on all four monitored rails. Fault management includes latchable CMP1–CMP4 outputs for source diagnosis, system-wide shutdown on internal/external faults, and configurable RST–FLT interaction via MS1/MS2 pins.

Key Specifications

Pinout & Package

36-lead plastic SSOP (5.3mm × 11.2mm), exposed pad optional for thermal relief. Pin 1 marked by dot; pin 19 is GND; pin 36 is ON.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC2928CG#PBF, LTC2927CG#PBF reduces channel count and removes negative rail capability but retains identical sequencing resolution and fault reporting. TPS652860RHAR integrates regulation but sacrifices voltage flexibility and external FET control-making it unsuitable for high-current or non-standard rail applications.

Availability

LTC2928CG#PBF is available at Aetrix Electronics and suitable for telecom infrastructure, FPGA/ASIC power management, and industrial PLC applications requiring stable component supply and long-term lifecycle support.

Supply support for LTC2928CG#PBF 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 precision analog and power management product lines with full technical documentation and long-term support.

The LTC2928CG#PBF belongs to Linear's high-accuracy power supply supervisory IC family, designed specifically for complex, multi-rail sequencing in telecom, computing, and industrial systems where reliability and diagnostic capability are critical.

FAQ

What is the maximum number of power supplies that can be sequenced using LTC2928CG#PBF?

LTC2928CG#PBF supports unlimited power supplies through cascading: each device controls up to four rails, and multiple LTC2928CG#PBF units connect via the CAS pin to extend sequencing capacity. The cascade protocol ensures deterministic handoff between adjacent time positions without timing skew or race conditions.

Does LTC2928CG#PBF support negative voltage monitoring?

Yes, LTC2928CG#PBF supports negative rail monitoring when VSEL is tied to VCC. In this mode, V1 accepts a resistive divider referenced to the buffered REF output (1.189V), enabling accurate undervoltage detection on negative supplies such as –1.2V or –5V without external op-amps.

How does the LTC2928CG#PBF generate its enable output voltage above VCC?

LTC2928CG#PBF uses an internal charge pump to generate VCC + 5.5V on EN1–EN4 outputs. This eliminates external level-shifters and directly drives the gate of standard N-channel MOSFETs used as high-side pass elements, ensuring robust turn-on even with low-VCC supplies like 3.3V.

What fault conditions cause the FLT pin to assert low on LTC2928CG#PBF?

LTC2928CG#PBF pulls FLT low for internal faults (e.g., undervoltage on any monitored rail, overvoltage on positive rails, power-good timeout) and external faults (e.g., OV pin pulled low, external signal applied to FLT). All EN outputs are forced low simultaneously, and CMP1–CMP4 latch to indicate fault origin.

Can LTC2928CG#PBF be powered solely from HVCC without connecting VCC?

Yes, LTC2928CG#PBF operates with HVCC only: the internal regulator delivers a stable 3.3V on VCC (±3.3%) when HVCC is between 7.2V and 16.5V. VCC can then power external circuitry up to 10mA, eliminating the need for a separate low-voltage supply rail.