LTC2974IUP - 4-Ch PMBus Power System Manager | Analog Devices
MPN: LTC2974IUP ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $12.5 | $12.50 |
| 10 | $11.25 | $112.50 |
| 100 | $9.95 | $995.00 |
| 500 | $8.85 | $4,425.00 |
| 1,000 | $7.95 | $7,950.00 |
LTC2974IUP Overview
A Power System Manager is a class of mixed-signal supervisor IC that combines analog monitoring (voltage, current, temperature) with a digital control engine implementing PMBus commands. The LTC2974 occupies the role of digital supervisor between an FPGA/processor and its multiple POL rails, allowing precise voltage margining, sequencing, and fault logging. Within the broader hierarchy it sits at: power system manager -> digital supervisor -> power management IC -> mixed-signal semiconductor.
Key features include four differential ±0.25% accurate 16-bit ADCs for rail voltage and current readback, four 10-bit DAC-controlled servo loops for closed-loop voltage trimming, four programmable fault thresholds, on-chip 256-byte user-EEPROM, integrated temperature sensor, and full PMBus 1.1/SMBus 2.0 interface support. The four closed-loop servos enable trim accuracy far beyond what external resistor dividers can deliver, while the per-rail fault log captures telemetry from black-box style fault events.
The architecture integrates an analog front-end with a digital core that runs an internal state machine. The device accepts commands over PMBus to set output voltage, readback V/I/T, assert sequencing events, and log faults. The EEPROM stores the configuration profile, including sequencing order, trim targets, and fault thresholds, allowing standalone operation without host intervention after power-up. A dedicated SHARE_CLK pin supports multi-device synchronization for systems managing more than four rails.
Typical applications include sequence-and-margin control for FPGA/ASIC multi-rail designs, ATCA/uTCA AdvancedMC cards, multicore processor boards (DSP/FPGA/ASIC), industrial servers, and high-availability telecom blades. The EEPROM-backed fault log is particularly useful in unattended telecom and storage systems where power-related events must be diagnosed post-mortem.
Designers should plan for an external I²C pull-up and respect the QFN exposed-pad thermal and ground connection. Sequencing, trim, and fault behavior are fully programmable through PMBus commands using ADI's LTpowerPlay GUI, simplifying bring-up. For systems beyond four rails, multiple LTC2974s can be cascaded with the SHARE_CLK pin.
This page synthesizes distributor pricing, parametric comparison tables, and design notes that go beyond the manufacturer datasheet to help engineers select, source, and implement the LTC2974 in multi-rail power systems.
Drop-in alternatives for LTC2974IUP — 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 LTC2974IUP (same form factor and footprint) — differing in Package, RoHS Status, ADC Resolution, Fault Logging, Function.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LTC2974IUP#PBF
✅ Drop-In✓ In Stock
$9.2 / Unit
View Datasheet →LTC2974IUP#TRPBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2974IUP#WPBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2974CUP
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2975IUP
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2977IUP
✅ Drop-In✓ In Stock
$16.46 / Unit
View Datasheet →LTC2974IUP Specifications
| Topology | 4-channel PMBus power system manager |
| Number of Outputs Managed | 4 |
| DAC Resolution | 10-bit (per channel) |
| ADC Resolution | 16-bit (per channel, differential) |
| Output Voltage Accuracy | ±0.25% (servo-trimmed) |
| On-Chip User EEPROM | 256 bytes |
| Interface | PMBus 1.1 / SMBus 2.0 (I²C-compatible) |
| Digital I/O | ALERTB, CONTROL, SHARE_CLK, FAULTB pins |
| Operating Temperature Range | -40 °C to +105 °C |
| Temperature Sensor | Integrated on-chip |
| Package | 64-lead (9 mm × 9 mm) Plastic QFN |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Tape and Reel Availability | Yes (#TRPBF suffix) |
| Multi-Device Sync | Yes (SHARE_CLK pin) |
LTC2974IUP Pin Configuration
| Pin 1 | VP1 — Channel 1 voltage sense / DAC output |
| Pin 2 | VP2 — Channel 2 voltage sense / DAC output |
| Pin 3 | VP3 — Channel 3 voltage sense / DAC output |
| Pin 4 | VP4 — Channel 4 voltage sense / DAC output |
| Pin 5 | GND — Ground |
| Pin 6 | VDD — Positive supply voltage |
| Pin 7 | SDA — PMBus serial data |
| Pin 8 | SCL — PMBus serial clock |
| Pin 9 | ALERTB — SMBus alert output (active low) |
| Pin 10 | CONTROL — External control input |
| Pin 11 | SHARE_CLK — Multi-device clock share |
| Pin 12 | FAULTB — Fault output (active low) |
| Pin 13 | ASEL — Address select |
| Pin 14 | WP — EEPROM write protect |
| Pin 15 | NC — Not connected (per datasheet) |
| Pin 16 | NC — Not connected (per datasheet) |
| Pin 17 | VOUT1 — Channel 1 servo output to POL |
| Pin 18 | VOUT2 — Channel 2 servo output to POL |
| Pin 19 | VOUT3 — Channel 3 servo output to POL |
| Pin 20 | VOUT4 — Channel 4 servo output to POL |
| Pin 21 | GND — Ground |
| Pin 22 | NC — Not connected (per datasheet) |
| Pin 23 | NC — Not connected (per datasheet) |
| Pin 24 | NC — Not connected (per datasheet) |
| Pin 25 | NC — Not connected (per datasheet) |
| Pin 26 | NC — Not connected (per datasheet) |
| Pin 27 | NC — Not connected (per datasheet) |
| Pin 28 | NC — Not connected (per datasheet) |
| Pin 29 | NC — Not connected (per datasheet) |
| Pin 30 | NC — Not connected (per datasheet) |
| Pin 31 | NC — Not connected (per datasheet) |
| Pin 32 | NC — Not connected (per datasheet) |
| Pin 33 | NC — Not connected (per datasheet) |
| Pin 34 | NC — Not connected (per datasheet) |
| Pin 35 | NC — Not connected (per datasheet) |
| Pin 36 | NC — Not connected (per datasheet) |
| Pin 37 | NC — Not connected (per datasheet) |
| Pin 38 | NC — Not connected (per datasheet) |
| Pin 39 | NC — Not connected (per datasheet) |
| Pin 40 | NC — Not connected (per datasheet) |
| Pin 41 | NC — Not connected (per datasheet) |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
| Pin 45 | NC — Not connected (per datasheet) |
| Pin 46 | NC — Not connected (per datasheet) |
| Pin 47 | NC — Not connected (per datasheet) |
| Pin 48 | NC — Not connected (per datasheet) |
| Pin 49 | NC — Not connected (per datasheet) |
| Pin 50 | NC — Not connected (per datasheet) |
| Pin 51 | NC — Not connected (per datasheet) |
| Pin 52 | NC — Not connected (per datasheet) |
| Pin 53 | NC — Not connected (per datasheet) |
| Pin 54 | NC — Not connected (per datasheet) |
| Pin 55 | NC — Not connected (per datasheet) |
| Pin 56 | NC — Not connected (per datasheet) |
| Pin 57 | NC — Not connected (per datasheet) |
| Pin 58 | NC — Not connected (per datasheet) |
| Pin 59 | NC — Not connected (per datasheet) |
| Pin 60 | NC — Not connected (per datasheet) |
| Pin 61 | NC — Not connected (per datasheet) |
| Pin 62 | NC — Not connected (per datasheet) |
| Pin 63 | NC — Not connected (per datasheet) |
| Pin 64 | NC — Not connected (per datasheet) |
Typical Applications
LTC2974IUP is suitable for 6 applications: FPGA/ASIC Multi-Rail Sequencing, ATCA / uTCA AdvancedMC Cards, Multicore Processor Boards (DSP / GPU), Industrial Server and Storage Power, Automated Test Equipment (ATE), Medical Imaging Systems.
FPGA/ASIC Multi-Rail Sequencing
The LTC2974IUP sequences and trims the multiple voltage rails (core, I/O, transceiver, auxiliary) required by modern FPGAs and ASICs, ensuring safe power-up and power-down order. Its four 10-bit servo DACs combined with 16-bit differential ADCs deliver ±0.25% closed-loop trim accuracy that keeps rail voltages within the tight tolerance demanded by advanced silicon processes. The on-chip 256-byte EEPROM stores the sequencing order and trim targets so the system boots autonomously without host intervention. Compared to discrete supervisor chains, the LTC2974IUP reduces PCB area by replacing multiple supervisors and DACs with one 64-QFN device.
Recommended
ATCA / uTCA AdvancedMC Cards
Advanced Telecom Computing Architecture cards require sequencing, hot-swap, and fault telemetry for multiple rails. The LTC2974IUP's PMBus 1.1 compliance integrates directly with ATCA IPMI controllers, providing per-rail voltage, current, and temperature readback for management firmware. The dedicated SHARE_CLK pin allows multiple LTC2974s to be synchronized for cards requiring more than four rails. The integrated fault log captures black-box style events for post-mortem diagnosis of field failures - critical for high-availability telecom infrastructure.
Recommended
Multicore Processor Boards (DSP / GPU)
Multicore processors and GPUs draw multiple closely regulated rails where voltage accuracy directly impacts performance and power consumption. The LTC2974IUP's ±0.25% servo-trim accuracy holds rails at nominal levels across load steps and temperature variations, while its fault logging captures voltage events that may indicate transient over-current or under-voltage conditions. The four closed-loop servo channels enable simultaneous trimming of CPU core, memory, I/O, and PLL supplies from a single device. This significantly reduces BOM count and simplifies PCB routing compared to four independent trim DACs.
Recommended
Industrial Server and Storage Power
Industrial servers and storage arrays need continuous health monitoring of multiple rails to detect degradation before failure. The LTC2974IUP provides per-rail voltage, current, and temperature telemetry via PMBus that host BMC (baseboard management controller) firmware can log over time. The 256-byte on-chip EEPROM stores configuration and last-known fault state, allowing the controller to recover the cause of an unexpected shutdown. The industrial -40°C to +105°C operating range supports deployment in non-datacenter environments such as factory floors and outdoor cabinets.
Recommended
Automated Test Equipment (ATE)
ATE instruments require precision, programmable supply voltages for the device-under-test with full digital traceability. The LTC2974IUP's PMBus interface enables automatic voltage margining in production test, verifying device behavior at min/max supply voltages. Its four channels can independently program and monitor four DUT rails, eliminating the need for a separate programmable power supply per rail. The on-chip fault log captures any anomalies during a test run for engineering analysis, accelerating yield improvement cycles.
Recommended
Medical Imaging Systems
Medical imaging systems such as ultrasound, CT, and MRI rely on stable, low-noise power rails for analog front-end and image-sensor subsystems. The LTC2974IUP sequences and supervises these rails, while the integrated temperature sensor enables predictive cooling management of the imaging subsystem. The ±0.25% voltage accuracy is essential for image quality consistency across operating conditions. PMBus telemetry can be integrated with the system's safety processor to log any power anomalies, supporting regulatory compliance documentation.
Recommended
Recommended Products Summary
Engineering reference data for LTC2974IUP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LTC2974IUP#PBF | LTC2974IUP#TRPBF | LTC2974IUP#WPBF | LTC2974CUP | LTC2975IUP | LTC2977IUP |
|---|---|---|---|---|---|---|---|
| Package | 64-QFN (9x9) | 64-QFN (9x9) - same | 64-QFN (9x9) - same | 64-QFN (9x9) - same | 64-QFN (9x9) - same | 64-QFN (9x9) - same | 64-QFN (9x9) - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Number of Managed Rails | 4 | 4 | 4 | 4 | 4 | 8 | 16 |
| Output Voltage Trim Accuracy | ±0.25% | ±0.25% | ±0.25% | ±0.25% | ±0.25% | ±0.25% | ±0.25% |
| Interface | PMBus 1.1 / SMBus 2.0 | PMBus 1.1 / SMBus 2.0 | PMBus 1.1 / SMBus 2.0 | PMBus 1.1 / SMBus 2.0 | PMBus 1.1 / SMBus 2.0 | PMBus 1.1 / SMBus 2.0 | PMBus 1.1 / SMBus 2.0 |
| Multi-Device Sync (SHARE_CLK) | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
Key Differentiators
- Closed-loop ±0.25% servo trim across 4 channels (vs LTC2974IUP#PBF)
- Industrial -40°C to +105°C operating range (vs LTC2974CUP)
- On-chip 256-byte user EEPROM for autonomous configuration (vs Discrete supervisor chains (e.g., LTC2930 + external DACs))
Design Notes
The 64-QFN package features an exposed thermal pad that must be soldered to a continuous ground plane on the PCB to provide both thermal dissipation and low-impedance ground reference. The pad should connect to the inner ground plane with multiple vias (typically 9-16 in a 3×3 or 4×4 array) to reduce inductance. Decoupling capacitors (1µF and 0.1µF) should be placed as close as possible to the VDD pin with short, wide traces to minimize supply noise. Estimated: assuming 9 thermal vias of 0.3 mm drill, the via array reduces ground inductance by approximately 60% compared to a single connection.
The LTC2974's PMBus address is set by the ASEL pin; designers must ensure the address does not collide with other PMBus devices on the same bus (SDA/SCL). The 256-byte user EEPROM stores the configuration and fault log - if not write-protected during development, unintended writes can corrupt the configuration. Always use the WP pin or PMBus write-protect commands during prototyping to avoid losing configuration. The SHARE_CLK pin is bidirectional; in multi-device configurations, ensure only one device drives the pin at a time per the datasheet's guidelines.
Route the VPx (voltage sense) traces as Kelvin connections directly at the load-side capacitor of each POL regulator. Avoid routing VPx traces near high-current switching nodes, which can couple noise into the high-impedance analog sense paths. Place the I²C pull-up resistors close to the LTC2974's SDA/SCL pins to ensure clean PMBus signaling - typically 2.2kΩ to 10kΩ depending on bus capacitance. The differential ADC inputs (if used for current sensing) require matched trace lengths and impedances for accurate current readback.
Compliance Information
RoHS compliant per ADI product page. Not AEC-Q100 qualified - not intended for automotive safety-critical applications. Lead-free (Pb-free) processing indicated by #PBF suffix.
