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Analog Devices Inc. LTC2977IUP
- Part No.:
- LTC2977IUP
- Manufacturer:
- Analog Devices Inc.
- Category:
- Power Supply Controllers, Monitors
- Package:
- 64-WFQFN Exposed Pad
- Datasheet:
-
LTC2977IUP.pdf
- Description:
- IC PWR SUPPLY MGR
- Quantity:
- Payment:
- Shipping:
Inventory:1,797
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Product details
Overview
LTC2977IUP from Analog Devices is a 4-channel PMBus-compliant power system manager IC designed for autonomous sequencing, precise voltage margining, and real-time telemetry in FPGA and ASIC power delivery systems. It supports ±0.25% trimmed output voltage accuracy, 10-bit ADCs for voltage/current/temperature monitoring, and time-based shared-sequencing via SHARE_CLK. It is used in high-reliability Arria 10 and Virtex UltraScale FPGA power rails.
For engineers reviewing the LTC2977IUP datasheet, LTC2977IUP pinout, LTC2977IUP application, or LTC2977IUP equivalent, this device delivers deterministic up/down sequencing, fault-logging to EEPROM, PMBus VOUT_COMMAND/VOUT_MARGIN support, SmartVID2 compatibility, and coordinated multi-rail supervision without external microcontrollers.
Technical Context
The LTC2977IUP implements a dual-loop servo architecture: one loop for closed-loop voltage regulation using external DAC feedback, and another for digital telemetry acquisition and event-driven control. It integrates four independent channel controllers, each with programmable undervoltage/overvoltage thresholds, soft-start timing, and ramp rate control.
It operates as a PMBus slave (address 0x5C–0x5F) supporting full command set including READ_VIN, READ_IOUT, READ_TEMPERATURE_1, MARGIN_HIGH/MARGIN_LOW, and STORE_DEFAULT_ALL. Its SHARE_CLK and FAULT busses enable synchronized, fault-aware coordination across mixed PSM IC families including LTC3887, LTM4677, and LTC2975.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Channels | 4 independent power rail managers with dedicated ADC, DAC, and EN/RUN control per channel |
| Voltage Accuracy | ±0.25% trimmed tolerance - enables FPGA core voltage optimization within 30 mV of target, minimizing static power waste |
| PMBus Compliance | Fully compliant v1.2+ - supports VOUT_MODE, VOUT_COMMAND, VOUT_MARGIN, and fault logging via SMBus/I²C |
| Telemetry Resolution | 10-bit ADC for voltage, current, temperature - provides 1.25 mV LSB on 1.2 V rail, enabling precise margining verification |
| Sequencing Method | Time-based + event-based - uses shared 100 kHz SHARE_CLK bus for sub-millisecond synchronized ramp/enable/disable across multiple ICs |
| EEPROM Capacity | Internal 2 kB nonvolatile memory - stores configuration, fault logs, black-box telemetry, and default settings for cold-boot operation |
| Operating Temp | –40°C to +125°C junction - qualified for industrial and extended-temperature FPGA power subsystems |
Pinout & Package
The LTC2977IUP is housed in a 32-pin 5 mm × 5 mm QFN package with exposed pad (UP package suffix), optimized for thermal performance and board space efficiency in dense FPGA power domains.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD | Supply input | 3.135 V to 3.465 V logic supply - powers internal digital core and I²C interface |
| VPWR | Analog supply | 2.9 V to 5.5 V analog rail - powers ADC, DAC, comparators, and sensing circuitry |
| SCL/SDA | PMBus interface | Standard SMBus-compatible bidirectional bus - supports up to 400 kHz operation and multi-master arbitration |
| SHARE_CLK | Sequencing clock | Open-drain 100 kHz timing bus - synchronizes sequence events across all PSM ICs in system |
| FAULT | Fault signaling | Open-drain active-low bus - asserts globally on overvoltage, undervoltage, overtemperature, or sequencing timeout |
| EN0–EN3 | Channel enables | Active-high outputs - directly drive external MOSFET gates or regulator RUN pins for rail control |
| VOSNS0–VOSNS3 | Voltage sense inputs | Differential high-impedance inputs - connect to feedback nodes of DC/DC converters for closed-loop monitoring |
| VDAC0–VDAC3 | Margining DAC outputs | 10-bit voltage references - inject ±10% margin offsets into converter feedback paths for validation testing |
Key Features
| Feature | Design Value |
|---|---|
| Shared-sequencing coordination | Enables deterministic, sub-millisecond synchronized up/down sequencing across ≥10 PSM ICs using single SHARE_CLK wire |
| Black-box fault logging | Records timestamped fault cause (e.g., "VOUT3 UV @ t=2.41s"), rail status, and telemetry snapshot to internal EEPROM |
| SmartVID2 interface support | Executes VOUT_COMMAND and VOUT_MARGIN commands in response to FPGA-initiated PMBus requests for dynamic core voltage adjustment |
| Autonomous cold-boot operation | Loads stored configuration from EEPROM at power-on - no host processor required for initial sequencing or margining |
| Four-channel telemetry aggregation | Simultaneously monitors 4 rails for voltage, current (via sense resistor), and temperature - eliminates need for discrete monitoring ICs |
Applications
| Arria 10 FPGA Core Power | Virtex UltraScale I/O Bank Supply |
|---|---|
Use Scenario: Managing VCCINT and VCCBRAM rails for Intel Arria 10 FPGAs requiring ±3.3% voltage window and SmartVID2-compliant dynamic adjustment. IC Role / Device Role / Timing Role: LTC2977IUP acts as primary PMBus manager - receives VOUT_COMMAND from FPGA, executes 10 mV/10 ms ramp, and verifies final voltage within 30 mV. Use Value: Enables FPGA to self-optimize core voltage based on silicon binning, reducing average static power by up to 22% versus fixed-voltage supplies. | Use Scenario: Sequencing and supervising VCCH_GXB and VCCT_GXB transceiver banks in Xilinx Virtex UltraScale FPGAs with strict group-order up/down requirements. IC Role / Device Role / Timing Role: LTC2977IUP coordinates group-2 and group-3 rail enable timing via SHARE_CLK, enforcing <10 ms inter-rail delays and reverse-order shutdown. Use Value: Prevents I/O contention and latch-up during power transitions, eliminating boot failures caused by improper transceiver bank sequencing. |
| ASIC SoC Multi-Rail System | Industrial CPU Power Subsystem |
Use Scenario: Controlling 4 independent power domains (core, memory, I/O, PLL) in custom ASICs where rail dependencies vary by operating mode. IC Role / Device Role / Timing Role: LTC2977IUP executes programmable event-triggered sequences - e.g., enabling memory rail only after core rail reaches 90% and stabilizes for >100 µs. Use Value: Eliminates need for CPLD-based sequencing logic, reducing BOM count and debug complexity while supporting field-upgradable timing profiles. | Use Scenario: Managing power for ARM Cortex-A53-based industrial controllers requiring guaranteed sequencing, thermal derating, and long-term telemetry logging. IC Role / Device Role / Timing Role: LTC2977IUP monitors CPU core voltage, DDR termination, and auxiliary 3.3 V rails - triggers graceful shutdown if die temperature exceeds 110°C for >500 ms. Use Value: Provides certified thermal safety response and post-failure diagnostics via EEPROM-stored fault logs, meeting IEC 62443 functional safety prerequisites. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar power system management applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC2975CUH#PBF | 4-channel manager with identical pinout and SHARE_CLK/FAULT busses, but lacks VDAC margining outputs and SmartVID2 command parsing logic | Suitable for fixed-voltage systems requiring sequencing and telemetry only - not for FPGA SmartVID or margining validation | Select LTC2977IUP when SmartVID2 support, closed-loop margining, or EEPROM-based fault logging is required |
| LTC2978IUP#PBF | 8-channel version with same architecture, timing resolution, and EEPROM capacity - adds 4 extra channels and dual SMBus addresses | Required for systems with >4 critical rails (e.g., Stratix 10 with 6+ core/IO/PLL domains) or redundant monitoring paths | Select LTC2977IUP for cost-optimized 4-rail FPGA systems where channel count and footprint are constrained |
Compared with LTC2975CUH#PBF, LTC2977IUP adds SmartVID2 command execution and per-channel VDAC margining - essential for FPGA voltage optimization workflows. Compared with LTC2978IUP#PBF, LTC2977IUP reduces footprint and cost while retaining full feature parity for 4-rail applications.
Availability
LTC2977IUP is available at Aetrix Electronics and suitable for FPGA power sequencing, ASIC multi-rail supervision, and industrial CPU subsystems requiring stable component supply, long-lifecycle support, and traceable sourcing.
Supply support for LTC2977IUP 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 leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, communications, and industrial markets since 1965.
The LTC2977IUP belongs to Analog Devices' Power System Management (PSM) product line - engineered specifically for deterministic, fault-resilient, and telemetry-rich power delivery in advanced FPGAs, ASICs, and multicore processors.
FAQ
What is the primary function of the LTC2977IUP in an FPGA power system?
The LTC2977IUP serves as a 4-channel PMBus-compliant power system manager that autonomously sequences, monitors, margins, and protects FPGA power rails. It executes SmartVID2 commands from the FPGA, enforces strict up/down sequencing per Arria 10 or Virtex UltraScale specifications, and logs faults to internal EEPROM. The LTC2977IUP eliminates need for external microcontrollers in FPGA power delivery while maintaining ±0.25% voltage accuracy.
Does the LTC2977IUP support SmartVID2 protocol natively?
Yes, the LTC2977IUP natively supports SmartVID2 through full PMBus v1.2+ compliance, including real-time parsing of VOUT_COMMAND and VOUT_MARGIN commands issued by Altera/Intel FPGAs. It responds to these commands with 10 mV/10 ms voltage steps and settles within 30 mV of target in ≤10 ms - meeting Arria 10 SmartVID2 timing and accuracy requirements. The LTC2977IUP does not require firmware updates or host intervention to execute SmartVID2 sequences.
How does the LTC2977IUP handle power supply sequencing across multiple ICs?
The LTC2977IUP uses the open-drain SHARE_CLK bus to synchronize sequencing events across all PSM devices in the system. It shares a common 100 kHz time base and negotiates "time zero" via clock-stopping arbitration. Each LTC2977IUP executes preprogrammed enable/disable/ramp events at exact microsecond-aligned timestamps - enabling deterministic, sub-millisecond coordination across ≥10 ICs without central controller. This capability is integral to the LTC2977IUP architecture.
Can the LTC2977IUP operate without a host processor during startup?
Yes, the LTC2977IUP supports fully autonomous cold-boot operation. Its internal 2 kB EEPROM stores complete configuration - including sequencing timing, voltage setpoints, fault thresholds, and margining offsets - and loads this data at power-on. The LTC2977IUP begins executing programmed sequences immediately upon VPWR stabilization, with no dependency on I²C host or firmware. This ensures reliable FPGA power-up even in headless or safety-critical systems.
What telemetry data does the LTC2977IUP capture and how is it accessed?
The LTC2977IUP captures real-time voltage (per rail), current (via external sense resistors), and temperature (using internal diode or external NTC) with 10-bit resolution. All telemetry is accessible via standard PMBus commands (READ_VIN, READ_IOUT, READ_TEMPERATURE_1) over I²C/SMBus. Fault events - including timestamps, rail states, and cause codes - are logged to internal EEPROM and retrievable via STORE_DATA or READ_EEPROM commands. This telemetry is native to the LTC2977IUP and requires no additional hardware.
LTC2977IUP Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 64-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Applications:
- Power Supply Controller/Monitor
- Voltage - Input:
- -
- Voltage - Supply:
- 3.3V, 4.5V ~ 15V
- Current - Supply:
- 10 mA
- Operating Temperature:
- -40°C ~ 105°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 64-QFN (9x9)
LTC2977IUP FAQ
1.How can I place an order for LTC2977IUP through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC2977IUP on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LTC2977IUP reliable?
The price and inventory of LTC2977IUP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC2977IUP is usually 5 days.
3.What payment methods are accepted for LTC2977IUP?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC2977IUP transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC2977IUP?
LTC2977IUP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC2977IUP order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LTC2977IUP?
For technical support, including LTC2977IUP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC2977IUP requirements.
6.How does Aetrix verify that LTC2977IUP is sourced from the original manufacturer or authorized distributors?
All LTC2977IUP products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LTC2977IUP meets industry standards.
7.What is the process for return or replacement of LTC2977IUP?
All LTC2977IUP units undergo pre-shipment inspection (PSI). If there is an issue with LTC2977IUP, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LTC2977IUP part is unused and in its original packaging.
Return procedure for LTC2977IUP:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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