Analog Devices Inc. LTC2978ACUP

Overview

LTC2978ACUP from Analog Devices is a 8-channel PMBus-compliant power system manager IC designed for autonomous sequencing, precise voltage margining, real-time telemetry, and fault logging in multi-rail FPGA and ASIC power systems. It supports ±0.25% trimmed output voltage accuracy, 10-bit ADCs per channel, and full PMBus 1.2 command set including VOUT_COMMAND, READ_VIN, READ_IOUT, and STORE_DEFAULT_ALL. It operates across –40°C to 125°C junction temperature and is used in high-reliability Arria 10 and Virtex UltraScale FPGA power delivery.

For engineers reviewing the LTC2978ACUP datasheet, LTC2978ACUP pinout, LTC2978ACUP application, or LTC2978ACUP equivalent, this device is selected for deterministic time-based sequencing, black-box fault logging with EEPROM, SmartVID2-compatible voltage adaptation, and coordinated multi-IC SHARE_CLK/FAULT bus operation in complex digital power systems.

Technical Context

The LTC2978ACUP implements an embedded 8-channel analog front end with independent 10-bit ADCs, programmable voltage/current/temperature thresholds, and dual 32-byte EEPROM for configuration and fault records. Its internal state machine executes time-based sequencing with microsecond resolution using the shared SHARE_CLK bus.

It supports both event-triggered and time-triggered sequencing modes, handles up/down sequencing of up to eight rails with configurable ramp rates and inter-rail delays, and provides PMBus-specified VOUT_MARGIN_HIGH/LOW commands for closed-loop voltage margining without external DACs.

Key Specifications

Pinout & Package

The LTC2978ACUP is housed in a 64-pin 9 mm × 9 mm QFN package with exposed thermal pad (UP package suffix), optimized for high-density PCB layouts and thermal dissipation in multi-phase power systems.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power system management applications.

Compared with LTC2978ACUP, the LTC2977CUH offers identical sequencing and telemetry capability at lower channel count and smaller footprint, while the LTC2975CUY sacrifices rail count to deliver higher-accuracy current sensing - making LTC2978ACUP the optimal choice for 8-rail FPGA/ASIC systems demanding full-feature integration without compromise.

Availability

LTC2978ACUP is available at Aetrix Electronics and suitable for FPGA power sequencing, ASIC voltage optimization, telecom multi-rail systems, industrial PLCs, and high-reliability embedded computing requiring stable component supply and long-term lifecycle support.

Supply support for LTC2978ACUP 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 is a global semiconductor leader specializing in high-performance analog, mixed-signal, and power management technologies for precision signal chain and power applications.

The LTC2978ACUP belongs to the Power System Management (PSM) product line, engineered specifically for autonomous, fault-resilient, and telemetry-rich power delivery in advanced FPGAs, ASICs, and multi-core processors.

FAQ

What is the primary function of the LTC2978ACUP in a power system?

The LTC2978ACUP serves as an autonomous power system manager that performs real-time voltage/current/temperature monitoring, time-based multi-rail sequencing, black-box fault logging, and PMBus-controlled voltage margining. Unlike basic supervisors, the LTC2978ACUP executes coordinated up/down sequences across eight rails using the SHARE_CLK bus and stores fault telemetry in on-chip EEPROM - making it essential for reliable FPGA and ASIC power delivery where deterministic behavior and field-debuggability are required. The LTC2978ACUP replaces discrete supervisors, timers, and telemetry ICs with a single integrated solution.

Does the LTC2978ACUP support SmartVID2 voltage negotiation for Altera Arria 10 FPGAs?

Yes, the LTC2978ACUP fully supports SmartVID2 via native PMBus 1.2 command implementation, including VOUT_MODE (to configure VID mode), VOUT_COMMAND (to accept dynamic voltage requests), and READ_VOUT (for closed-loop verification). It meets the Arria 10 SmartVID2 timing requirements: accepting new voltage commands every 10 ms, stepping in 10 mV increments, and settling within ±30 mV of target within 10 ms. The LTC2978ACUP's ±0.25% trimmed voltage accuracy ensures the commanded SmartVID voltage remains within FPGA core specification limits across temperature and load - a requirement not met by general-purpose PMBus devices.

How does the LTC2978ACUP handle power supply fault conditions during operation?

The LTC2978ACUP detects faults-including overvoltage, undervoltage, overtemperature, and current limit violations-using independently programmable thresholds per channel. Upon detection, it asserts the ALERTB pin, logs timestamped rail states and environmental data to its dual 32-byte EEPROM, and can trigger coordinated shutdown via the open-drain FAULT bus. When linked with other PSM ICs, the entire system halts sequencing, disables affected rails, and initiates safe energy dissipation - all without host processor intervention. This black-box logging capability is retained across power cycles, enabling forensic analysis of field failures. The LTC2978ACUP's fault response is deterministic and repeatable, unlike software-based solutions.

Can the LTC2978ACUP perform autonomous down-sequencing for FPGA power-down?

Yes, the LTC2978ACUP supports fully autonomous, configurable down-sequencing that complies with FPGA manufacturer specifications such as Altera Arria 10's Group 1/2/3 shutdown order. It executes reverse-order rail disablement with programmable delays, monitors residual rail voltages during discharge, and coordinates energy dissipation using external FETs triggered via GPIO pins. Its internal state machine ensures inter-rail timing compliance even during brownout conditions, and fault logging captures pre-shutdown rail states. This capability eliminates reliance on host firmware or CPLD logic for safe, repeatable power-down - a key differentiator of the LTC2978ACUP versus basic sequencers.

What package type and thermal characteristics does the LTC2978ACUP use?

The LTC2978ACUP is packaged in a 64-pin 9 mm × 9 mm QFN (UP package) with exposed thermal pad, rated for operation from –40°C to +125°C junction temperature. Its thermal resistance θ_JA is 26.5°C/W (with 2-in² 2-oz copper), enabling reliable operation in high-power-density FPGA power systems without forced airflow. The exposed pad must be soldered to a minimum 200 mm² copper pour for optimal heat transfer. This package supports automated optical inspection and reflow compatibility per IPC-J-STD-020, and is RoHS-compliant. The LTC2978ACUP's thermal design allows sustained 8-channel telemetry acquisition and sequencing execution under full industrial temperature stress.