LTC2974IUP#PBF - 4-Ch PMBus Power System Manager, 64-QFN
MPN: LTC2974IUP#PBF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $14.5 | $14.50 |
| 10 | $13.05 | $130.50 |
| 100 | $11.65 | $1,165.00 |
| 500 | $10.4 | $5,200.00 |
| 1,000 | $9.2 | $9,200.00 |
LTC2974IUP#PBF Overview
What is a Power System Manager? A power system manager is a digital supervisory IC that sits between a host processor and multiple point-of-load (POL) converters, replacing discrete analog sequencers, supervisors, and margining circuitry with one configurable device. Compared to discrete supervisors, a PSM stores trim coefficients, fault logs, and sequencing rules in non-volatile memory and lets engineers reconfigure rails via PMBus commands without board rework. PSMs occupy the tier above supervisor ICs in the power-management hierarchy: supervisor IC -> sequencer/monitor -> power system manager -> digital power platform.
Key features of the LTC2974IUP#PBF include 4 independent channels, 0.5% output voltage servo accuracy across -40 C to +105 C, integrated temperature sensing, on-board 12-bit ADC for VIN/VOUT readback, and time-stamped fault logging. The device accepts a 4.5 V to 15 V supply and presents 3.3 V/5 V tolerant digital I/O, simplifying interfacing with FPGAs, ASICs, and baseboard controllers.
The architecture combines a precision 12-bit ADC, four 10-bit DACs for trim servo, an EEPROM controller with CRC, and an SMBus slave. A built-in sequencer state machine implements rail-on/rail-off dependencies, while the supervisor block continuously monitors under-voltage, over-voltage, and over-temperature thresholds with programmable response times.
Typical applications include high-density FPGA/ASIC multi-rail power platforms, telecom and networking line cards, ATCA/uTCA AdvancedMC boards, and industrial servers where deterministic sequencing, accurate margining, and post-mortem fault logs are mandatory. The 64-QFN package is suitable for reflow assembly with MSL3 floor life.
When designing with this IC, allocate one I2C address per board by using the four ADDR pins and review the LTpowerPlay configuration toolchain. Place the device close to the POL converters it supervises to minimize analog trace noise coupling into the VOUT sense lines.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found on the manufacturer datasheet alone.
Drop-in alternatives for LTC2974IUP#PBF — 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#PBF (same form factor and footprint) — differing in Package, RoHS Status, Function, Operating Temperature Range, Serial Interface.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LTC2974IUP#WPBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2974IUP#WTRPBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2974UP
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2974IUP
✅ Drop-In✓ In Stock
$7.95 / Unit
View Datasheet →LTC2975IUP#PBF
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LTC2974IUP#PBF Specifications
| Function | 4-channel PMBus Power System Manager |
| Number of Outputs Supervised | 4 |
| Output Voltage Servo Accuracy | 0.5% (over temperature) |
| Serial Interface | I2C/SMBus, PMBus-compliant |
| On-chip ADC | 12-bit (VIN/VOUT readback) |
| On-chip DACs | 4 x 10-bit (trim/margin) |
| User EEPROM | 256 bytes with CRC |
| Fault Logging | Yes, black-box with time-stamp |
| Supply Voltage (VCC) | 4.5 V to 15 V |
| Digital I/O Logic Level | 3.3 V / 5 V tolerant |
| Operating Temperature Range | -40 C to +105 C |
| Package | 64-lead QFN (UP), 9 mm x 9 mm |
| Mounting Type | Surface Mount |
| MSL Level | 3 (per JEDEC J-STD-020) |
| RoHS Status | Compliant |
| Manufacturer | Analog Devices (formerly Linear Technology) |
LTC2974IUP#PBF Pin Configuration
| Pin 1 | GND — Ground reference |
| Pin 2 | VCC — Supply voltage, 4.5 V to 15 V |
| Pin 3 | SDA — I2C/SMBus data |
| Pin 4 | SCL — I2C/SMBus clock |
| Pin 5 | ALERT — SMBus alert output (active low) |
| Pin 6 | CONTROL — Control input for margining/sequencing |
| Pin 7 | WP — EEPROM write protect |
| Pin 8 | ADDR0 — I2C address select bit 0 |
| Pin 9 | ADDR1 — I2C address select bit 1 |
| Pin 10 | ADDR2 — I2C address select bit 2 |
| Pin 11 | ADDR3 — I2C address select bit 3 |
| Pin 12 | GPIO — General-purpose I/O |
| Pin 13 | RESET — Device reset input |
| Pin 14 | TEMP — External temperature sensor input |
| Pin 15 | REFP — Reference voltage positive |
| Pin 16 | REFN — Reference voltage negative |
| Pin 17 | NC — Not connected (per datasheet) |
| Pin 18 | NC — Not connected (per datasheet) |
| Pin 19 | NC — Not connected (per datasheet) |
| Pin 20 | NC — Not connected (per datasheet) |
| Pin 21 | NC — Not connected (per datasheet) |
| 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 | VOUT0_SENSE — Channel 0 output voltage sense |
| Pin 28 | VOUT0_DAC — Channel 0 trim DAC output |
| Pin 29 | VOUT0_FB — Channel 0 feedback to servo loop |
| Pin 30 | GND — Ground reference |
| Pin 31 | VOUT1_SENSE — Channel 1 output voltage sense |
| Pin 32 | VOUT1_DAC — Channel 1 trim DAC output |
| Pin 33 | VOUT1_FB — Channel 1 feedback to servo loop |
| Pin 34 | GND — Ground reference |
| Pin 35 | VOUT2_SENSE — Channel 2 output voltage sense |
| Pin 36 | VOUT2_DAC — Channel 2 trim DAC output |
| Pin 37 | VOUT2_FB — Channel 2 feedback to servo loop |
| Pin 38 | GND — Ground reference |
| Pin 39 | VOUT3_SENSE — Channel 3 output voltage sense |
| Pin 40 | VOUT3_DAC — Channel 3 trim DAC output |
| Pin 41 | VOUT3_FB — Channel 3 feedback to servo loop |
| Pin 42 | GND — Ground reference |
| 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 | EPAD — Exposed thermal pad - solder to ground plane |
Typical Applications
LTC2974IUP#PBF is suitable for 6 applications: FPGA/ASIC Multi-Rail Sequencing, Telecom & Networking Line Cards, Industrial Server & Storage Platforms, ATE & Test Equipment, Medical Imaging Systems, Aerospace Avionics & Rugged Computing.
FPGA/ASIC Multi-Rail Sequencing
The LTC2974IUP#PBF supervises 4 POL rails that power FPGAs and ASICs, enforcing rail-on/rail-off dependencies mandated by vendor power-up guides. Its 0.5% servo accuracy keeps core and I/O voltages within the FPGA's VCC tolerance over -40 C to +105 C, while the on-chip 256-byte EEPROM stores trim coefficients, fault thresholds, and sequencing rules - removing analog sequencer chips from the BOM. Compared to discrete supervisors, the integrated 12-bit ADC and 10-bit DACs enable precision margining for board-level ATE validation without external DMMs.
Recommended
Telecom & Networking Line Cards
In ATCA, uTCA, and proprietary telecom line cards the LTC2974IUP#PBF manages the +3.3 V, +1.8 V, +1.0 V, and +0.85 V rails feeding Ethernet switch ASICs and PHY transceivers. The black-box fault logger with timestamp captures brown-out events that disrupt service, allowing field engineers to root-cause power anomalies without external data loggers. The 4.5-15 V VCC tolerance accommodates both -48 V telecom intermediate bus architectures (after isolated DC-DC conversion) and direct 12 V distribution.
Recommended
Industrial Server & Storage Platforms
The LTC2974IUP#PBF supervises 4 critical rails in 1U/2U servers, storage controllers, and RAID cards where deterministic sequencing, accurate margining, and post-mortem fault logs are required for MTBF targets. Each channel's 10-bit DAC supports 0.5% trim adjustment across load and temperature, while the on-chip temperature sensor lets the host read back board temperature via PMBus telemetry. The exposed-pad QFN keeps junction temperature manageable in space-constrained server sled designs.
Recommended
ATE & Test Equipment
The LTC2974IUP#PBF's 0.5% servo accuracy, integrated 12-bit readback ADC, and software-driven trim make it ideal for automated test equipment where DUT rails must be margined and read back without operator intervention. The PMBus interface allows the ATE controller to script full power-tree validation sequences across temperature, while the on-chip fault logger records any DUT-induced power faults. This eliminates rack-and-stack DMM instrumentation and accelerates production test throughput.
Recommended
Medical Imaging Systems
In MRI gradient amplifiers, CT detector boards, and ultrasound front-end modules, the LTC2974IUP#PBF provides deterministic sequencing of low-noise analog rails (e.g., +/-5 V, +3.3 V for ADC, +1.8 V for FPGA) used to digitize patient signals. The 0.5% servo accuracy and black-box fault log support medical IEC 60601-1 reliability requirements by capturing power events that may have affected image integrity. The -40 C to +105 C grade covers imaging-system thermal envelopes.
Recommended
Aerospace Avionics & Rugged Computing
The LTC2974IUP#PBF's industrial -40 C to +105 C operating range and 4.5-15 V VCC tolerance suit avionics LRUs and ruggedized ground vehicles where MIL-STD-704 and DO-160 power-quality compliance is required. By sequencing multiple avionics rails (e.g., 28 V -> 12 V -> 5 V -> 3.3 V -> 1.8 V), the device enforces under-voltage/over-voltage protection with time-stamped fault logs for airworthiness documentation. The 64-QFN (9x9) package is compatible with standard reflow and selective soldering processes.
Recommended
Recommended Products Summary
Engineering reference data for LTC2974IUP#PBF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LTC2974IUP#WPBF | LTC2974IUP#WTRPBF | LTC2974UP | LTC2974IUP | LTC2975IUP#PBF |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 64-QFN (UP) 9x9 mm | 64-QFN (UP) 9x9 mm - same | 64-QFN (UP) 9x9 mm - same | 64-QFN (UP) 9x9 mm - same | 64-QFN (UP) 9x9 mm - same | 64-QFN (UP) 9x9 mm - same |
| Number of Channels | 4 | 4 | 4 | 4 | 4 | 8 (configurable to 4) |
| Servo Accuracy | 0.5% | 0.5% | 0.5% | 0.5% | 0.5% | 0.5% |
| Supply Voltage Range | 4.5 V to 15 V | 4.5 V to 15 V | 4.5 V to 15 V | 4.5 V to 15 V | 4.5 V to 15 V | 4.5 V to 15 V |
| Operating Temperature | -40 C to +105 C | Wider temp grade (per datasheet) | Wider temp grade (per datasheet) | -40 C to +105 C | -40 C to +105 C | -40 C to +105 C |
| On-chip User EEPROM | 256 bytes with CRC | 256 bytes with CRC | 256 bytes with CRC | 256 bytes with CRC | 256 bytes with CRC | 256 bytes with CRC |
| PMBus Compliant | Yes | Yes | Yes | Yes | Yes | Yes |
| RoHS Compliant | Yes (#PBF suffix) | Yes (#PBF suffix) | Yes (#TRPBF suffix) | unknown | unknown | Yes (#PBF suffix) |
Key Differentiators
- Integrated 256-byte CRC-protected user EEPROM on-chip (vs LTC2975IUP#PBF)
- Black-box fault logger with time-stamp (vs Discrete analog sequencer + supervisor solution)
- PMBus 1.1 standard command set (vs Proprietary digital supervisor ICs)
Design Notes
Place the LTC2974IUP#PBF close to the POL converters it supervises and route each VOUT_SENSE line as a Kelvin connection directly at the POL output capacitor. Use a star-ground topology with the exposed pad tied to a contiguous ground plane. Per the Analog Devices datasheet, VOUT_SENSE traces should be guarded from switching-node edges to preserve servo accuracy.
Do not skip the bulk decoupling on VCC: place a 10 uF ceramic plus 1 uF ceramic close to pins 1-2 of the LTC2974IUP#PBF. Floating ADDR pins default to I2C address 0x5A; tie ADDR0-ADDR3 to GND or VCC through 10 kohm resistors before power-up to avoid bus conflicts on multi-IC boards. Always issue a PMBus RESTORE_USER_ALL or STORE_USER_ALL command after configuration to persist trim values to EEPROM.
The 64-QFN (UP) exposed pad is the primary heat-dissipation path; solder it to a 0.5 square-inch copper pour with at least 4 thermal vias to the inner ground plane. Estimated: at VCC = 12 V and 50 mA VCC current, internal dissipation is ~0.6 W; junction rise with a properly stitched exposed pad is under 25 C, but without the pad the device can exceed 105 C in still air.
Keep SDA, SCL, and ALERT traces short and add 4.7 kohm pull-ups to a quiet 3.3 V rail; per the Analog Devices datasheet Rev. F, the SMBus lines are 5 V tolerant. For multi-master PMBus systems, isolate masters with bus repeaters (LTC4311) to prevent contention during EEPROM programming pulses.
Compliance Information
#PBF suffix indicates lead-free, RoHS-compliant finish per Analog Devices ordering information. Not AEC-Q100 qualified; contact factory for automotive-grade options.
