LTC2977IUP - 8-Ch PMBus Power System Manager | ADI
MPN: LTC2977IUP ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $22.5 | $22.50 |
| 10 | $21.2 | $212.00 |
| 100 | $19.1 | $1,910.00 |
| 500 | $17.85 | $8,925.00 |
| 1,000 | $16.46 | $16,460.00 |
LTC2977IUP Overview
A Power System Manager is a digital supervisor IC placed above point-of-load converters on a board's power tree; it interfaces to the host through PMBus (Power Management Bus) and replaces discrete supervisors, DACs, and watchdog timers with a single configurable device. The LTC2977 sits at the supervisory tier of the power management hierarchy: PMBus controller -> power system manager -> supervisor/monitor -> power management IC (PMIC) -> voltage regulator -> point-of-load converter.
Key features include 8 independent channels, integrated 14-bit ADC for voltage/current readback, programmable OV/UV/OC/UC thresholds, fault logging with black-box EEPROM, closed-loop trim (servo) of any DC-DC converter, and per-rail margining. The IUP suffix denotes the -40 C to +105 C industrial temperature grade. Per the manufacturer datasheet, this part is recommended for new designs and supports 1 ku list pricing starting from $16.46 as of 2026-10-08.
The architecture combines an ARM-based M0 host core with hardware timers and analog comparators, allowing the IC to assert PG (power-good) and ALERTB lines autonomously even without host intervention. PMBus commands support power supply sequencing, precision point-of-load voltage adjustment and margining per the datasheet functional description.
Typical applications include sequencing and trimming FPGA/processor core and memory rails in telecom and datacom boards, server and storage backplanes with N+1 redundancy, industrial PLC power trees, and digital health monitoring of point-of-load converters in test equipment.
When designing with the LTC2977IUP, observe the 4.5 V to 15 V VDD range and decouple the 3.3 V AUX rail with a 1 uF X7R ceramic close to the pin. Always enable the internal black-box fault log EEPROM before relying on unattended fault capture.
This page synthesizes distributor pricing, same-brand and cross-brand drop-in alternatives, and practical design notes not consolidated on any single distributor or manufacturer page.
Drop-in alternatives for LTC2977IUP — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with LTC2977IUP (same form factor and footprint) — differing in ADC Resolution, Interface, Package, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LTC2977IUP#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2977CUP
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2978AIUP#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2977IUP#WTRPBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2977BIUP
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2977IUP Specifications
| Function | 8-Channel PMBus Power System Manager |
| Channels | 8 |
| Supply Voltage (VDD) | 4.5 V to 15 V |
| Auxiliary Supply (VAA/3V3) | 3.3 V |
| Supply Current | 10 mA typical |
| Interface | PMBus / I2C-compatible SMBus |
| ADC Resolution | 14-bit (per datasheet functional description) |
| Operating Temperature | -40 C to +105 C (I grade) |
| Package | 64-Pin QFN (9 mm x 9 mm) with exposed pad |
| Mounting Type | Surface Mount |
| Fault Logging | Internal black-box EEPROM |
| Trim / Margining | Yes, per-rail closed-loop servo |
| MSL Level | 3 (per JEDEC J-STD-020) |
| RoHS Status | Compliant (#PBF suffix) |
LTC2977IUP 64-pin qfn (9 mm x 9 mm) with exposed pad Pin Configuration Guide
Pin configuration for LTC2977IUP (64-pin qfn (9 mm x 9 mm) with exposed pad package). Pin numbering, functions, and connection diagrams are defined in the manufacturer datasheet. Refer to it for the exact footprint and soldering guidelines.
No detailed pinout data available for LTC2977IUP.
Refer to the datasheet for full pin configuration.
Typical Applications
LTC2977IUP is suitable for 7 applications: FPGA/Processor Power Sequencing, Server & Storage Backplane Monitoring, Industrial PLC & Factory Automation, Telecom & Networking Equipment, Test & Measurement Instrumentation, Medical Imaging & Patient Monitoring, Aerospace & Avionics Power Conditioning.
FPGA/Processor Power Sequencing
The LTC2977IUP's 8 independent channels and per-rail sequencing timers make it ideal for sequencing FPGA core, transceiver, and DDR rails in mid-to-large systems. Per the manufacturer datasheet, the device supports programmable ramp rates, time slots, and dependency tracking, allowing complex multi-rail power-up profiles for SoCs that demand precise rail-to-rail timing. The 4.5 V to 15 V VDD range accepts 5 V and 12 V intermediate buses typically used for FPGA power trees.
Recommended
Server & Storage Backplane Monitoring
In server, storage, and switching backplanes the LTC2977IUP provides telemetry and fault logging for up to 8 rails per device, with the internal black-box EEPROM capturing OV/UV/OC events even when the host is offline. Per the manufacturer datasheet, the IC's 14-bit ADC delivers accurate voltage and current readback through PMBus, supporting remote health monitoring and predictive maintenance. Industrial temperature grade (-40 C to +105 C) covers harsh backplane inlet temperatures.
Recommended
Industrial PLC & Factory Automation
PLC power trees in factory automation environments combine analog I/O, digital logic, and communication rails that must power up and down in a specific order. The LTC2977IUP, rated -40 C to +105 C, supports up to 8 rails of sequencing, trimming, and fault supervision through PMBus, replacing a rack of discrete supervisors. Per the datasheet, integrated margining simplifies production-board characterization and field calibration for analog measurement modules.
Recommended
Telecom & Networking Equipment
Telecom shelves and router line cards require per-rail sequencing, hot-swap coordination, and extensive fault logging. The LTC2977IUP, with its 4.5 V to 15 V VDD range, accepts standard -48 V isolated backplane rails and provides 8 channels of supervision. Per the manufacturer datasheet, the device logs faults to its internal EEPROM, enabling post-mortem analysis without host intervention - critical for unattended remote sites.
Recommended
Test & Measurement Instrumentation
In automated test equipment and bench instruments, the LTC2977IUP provides deterministic rail sequencing for ADC/DAC references, DAC bias, and analog front-end power. The device's 14-bit ADC readback, per the manufacturer datasheet, supports closed-loop trim that compensates for resistor-divider tolerances and reference drift, improving measurement accuracy. Industrial temperature rating makes the part suitable for both bench and field deployments.
Recommended
Medical Imaging & Patient Monitoring
Multi-rail medical devices such as ultrasound carts and patient monitors require fail-safe power-up sequencing and continuous fault supervision. The LTC2977IUP supports per-rail OV/UV/OC supervision, fault logging, and closed-loop trim, ensuring stable bias for analog front-end and DSP rails. The industrial temperature grade and lead-free RoHS-compliant packaging (#PBF) help meet medical equipment environmental and reliability requirements.
Recommended
Aerospace & Avionics Power Conditioning
Avionics line-replaceable units demand precise, deterministic multi-rail sequencing and fault logging across wide temperature ranges. The LTC2977IUP, rated -40 C to +105 C and qualified to manufacturer automotive/extended flow (#WTRPBF variant), meets many avionics power management requirements. The device's internal fault EEPROM captures pre-shutdown telemetry that supports maintenance investigations after in-flight events.
Recommended
Recommended Products Summary
Engineering reference data for LTC2977IUP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LTC2977IUP#PBF | LTC2977CUP | LTC2978AIUP#PBF | LTC2977IUP#WTRPBF | LTC2977BIUP |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 64-pin QFN (9 mm x 9 mm) | 64-pin QFN (9 mm x 9 mm) - same | 64-pin QFN (9 mm x 9 mm) - same | 64-pin QFN - same | 64-pin QFN (9 mm x 9 mm) - same | 64-pin QFN (9 mm x 9 mm) - same |
| Channels | 8 | 8 | 8 | 8 (extended feature) | 8 | 8 |
| Supply Voltage (VDD) | 4.5 V to 15 V | 4.5 V to 15 V | 4.5 V to 15 V | wider range | 4.5 V to 15 V | 4.5 V to 15 V |
| Temperature Grade | -40 C to +105 C (Industrial) | -40 C to +105 C | 0 C to +70 C (Commercial) | Industrial / AEC-Q100 ready | -40 C to +125 C (Automotive) | -40 C to +105 C |
| Interface | PMBus / SMBus | PMBus / SMBus | PMBus / SMBus | PMBus / SMBus | PMBus / SMBus | PMBus / SMBus |
| ADC Resolution | 14-bit | 14-bit | 14-bit | 14-bit (higher accuracy) | 14-bit | 14-bit |
| RoHS | Yes (#PBF suffix) | Yes | Yes | Yes | Yes | Yes |
Key Differentiators
- Industrial temperature grade standard on the IUP part number (vs LTC2977CUP)
- Pin-compatible upgrade path to extended feature set (vs LTC2978AIUP#PBF)
- Wide-temp automotive grade tape-and-reel variant available (vs LTC2977IUP#WTRPBF)
Design Notes
Estimated: at VDD = 12 V and I_DD = 10 mA typical (per datasheet), the LTC2977IUP dissipates approximately 120 mW on its VDD pin; designers should keep VDD on a separate rail (e.g. tap from the 12 V intermediate bus) and decouple with a 1 uF X7R 25 V ceramic within 2 mm of the VDD pin to prevent noise coupling into analog ADC readings.
The 64-pin QFN (9 mm x 9 mm) exposed pad carries the primary thermal path. Connect the EP to a continuous inner-plane copper pour (at least 1 square inch of 2 oz copper) with at least 12 thermal vias to a back-side ground plane. Without this, theta_JA rises above the datasheet 28 C/W rating and channel-to-channel thermal drift can corrupt ADC readback above 85 C.
Route PMBus SDA/SCL traces as a daisy-chain between devices and place a 2.2 kohm pull-up to 3.3 V AUX within 50 mm of the farthest device. Keep VSESEnSET traces short and away from switching converter switch-node traces to avoid injected common-mode noise that would skew closed-loop trim measurements. The exposed pad must be soldered to the board ground plane for both thermal and electrical reference.
Do not leave the 3.3 V AUX supply unpowered while VDD is present; the I2C pull-ups and ALERTB line are referenced to AUX and can float mid-rail. Always issue a CLEAR_FAULTS command after a fault event before reading telemetry, otherwise the LTC2977IUP returns stale data from the black-box EEPROM and the host mis-diagnoses the board state.
Compliance Information
RoHS compliance confirmed via the #PBF suffix on the part number. Automotive-grade variants exist as #WPBF / #WTRPBF - the standard LTC2977IUP is not AEC-Q100 qualified; choose the LTC2977IUP#WPBF for automotive designs.
