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Analog Devices Inc. LTM4681IY
- Part No.:
- LTM4681IY
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Converters
- Package:
- 330-BBGA Module
- Datasheet:
-
LTM4681IY.pdf
- Description:
- QUAD 30A OR SINGLE 120A UMODULE
- Quantity:
- Payment:
- Shipping:
Inventory:2,342
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Product details
Overview
LTM4681IY from Analog Devices is a quad-output, digitally managed µModule® DC/DC regulator delivering up to 31.25A per channel (125A total), with PMBus interface, integrated 16-bit ΔΣ ADC, ±0.5% DC output voltage accuracy over temperature, and 400kHz I²C-compatible serial interface. It serves as a high-density, telemetry-enabled power solution for multi-rail server, AI accelerator, and FPGA core supply applications.
For engineers reviewing the LTM4681IY datasheet, LTM4681IY pinout, LTM4681IY application, or LTM4681IY equivalent, this page delivers verified technical context on its quad-channel analog control loops, input current sensing capability, programmable soft-start/sequencing, real-time telemetry polling (up to 125Hz), and BGA package thermal performance - all critical for high-reliability digital power system design.
Technical Context
The LTM4681IY integrates four independent, digitally configurable analog PWM control loops with EEPROM-based configuration storage, enabling precise per-channel voltage, current limit, sequencing, and fault response settings. Each channel features differential output voltage sensing (VOSNS±), integrated input current sense amplifier, and dedicated thermal monitoring via TSNS pins.
Its PMBus 1.3-compliant interface supports full telemetry readback (input/output voltage/current, temperature, uptime, peak values) and writeable control (margining, slew rate, OV/UV thresholds, frequency, phasing). The device operates across 4.5V–16V input and delivers 0.5V–3.3V outputs with ±4% current readback accuracy from 0°C to 125°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Configuration | Quad 31.25A or single 125A configurable output array; enables flexible rail partitioning for multi-core processors. |
| Input Voltage Range | 4.5V to 16V DC; supports standard 5V, 12V intermediate bus architectures without external pre-regulation. |
| Output Voltage Range | 0.5V to 3.3V per channel; digitally programmable in 244µV LSB steps with ±0.5% DC accuracy over –40°C to 125°C. |
| Current Readback Accuracy | ±4% from 0°C to 125°C; enables accurate load-line calibration and dynamic power budgeting in real time. |
| Serial Interface | 400kHz PMBus-compliant I²C; supports telemetry polling up to 125Hz and full configuration via LTpowerPlay GUI. |
| Package Dimensions | 15mm × 22mm × 8.17mm BGA; SnPb finish (LTM4681IY#PBF); bottom-side thermal pad enables efficient heat transfer to PCB. |
| Thermal Performance | θJCbottom = 1.4°C/W; supports continuous 31.25A/channel operation with proper board-level thermal design. |
Pinout & Package
The LTM4681IY is housed in a 330-ball BGA package (15mm × 22mm × 8.17mm) with SnPb terminal finish, optimized for high-current power delivery and thermal dissipation. Bottom-side thermal pad requires solder paste stencil and reflow profile alignment per Analog Devices' assembly guidelines.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT0–VOUT3 | Regulated output voltage terminals | Four independent power outputs; each supports up to 31.25A with differential remote sensing (VOSNSn±). |
| IN_01+/IN_01−, IN_23+/IN_23− | Differential input current sense inputs | Enable accurate real-time input current measurement per channel pair (01 and 23) with integrated amplifier. |
| PGOOD0–PGOOD3 | Power-good status outputs | Open-drain signals indicating valid regulation per channel; used for sequencing and system-level fault coordination. |
| FAULT0–FAULT3 | Fault interrupt outputs | Active-low, open-drain pins asserting on OV, UV, OT, OC, or timing faults; support hardware-level fault propagation. |
| SDA_01/SDA_23, SCL_01/SCL_23 | PMBus data/clock lines | Dual isolated I²C buses (01 and 23) allow independent communication with two controller domains or redundancy. |
| SHARE_CLK_01/SHARE_CLK_23 | Phase synchronization clocks | Enable interleaved switching between channel pairs to reduce input/output ripple and improve EMI performance. |
| TSNS0–TSNS3 | External temperature sense inputs | Accept ΔVBE-based remote diode readings for per-rail thermal monitoring and derating control. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 16-bit ΔΣ ADC | Enables simultaneous high-resolution telemetry of voltage, current, temperature, and uptime without external converters. |
| Digital soft-start/stop with programmable slew rate | Prevents inrush current and ensures controlled ramp-up/down across all channels, critical for ASIC/FPGA power integrity. |
| EEPROM with ECC | Stores factory- and user-defined configurations (voltage, sequencing, fault thresholds) with error correction for field reliability. |
| Parallel and current-share capability | Supports stacking multiple LTM4681IY modules for >125A loads using SHARE_CLK and ALERT signaling for synchronized operation. |
| True input current sensing | Provides direct, calibrated measurement of total input current per channel pair-essential for power budgeting and efficiency optimization. |
Applications
| AI Accelerator Core Supply | Multi-Core CPU VR13/VR14 Compliance |
|---|---|
|
Use Scenario: Powering heterogeneous compute tiles in NVIDIA H100 or AMD MI300X accelerators requiring tightly regulated, dynamically scaled voltages under rapid load transients. IC Role / Device Role / Timing Role: Quad-channel µModule serving as primary core voltage regulator with per-rail telemetry, phase interleaving, and PMBus-controlled margining for AVS/FCCM. Use Value: Delivers <30µs transient settling time and ±0.5% DC accuracy, enabling aggressive voltage scaling while maintaining silicon reliability. |
Use Scenario: Delivering compliant VDD/VDDIO rails to x86 CPUs in enterprise servers, meeting VR13/VR14 specification for load-line, transient response, and telemetry reporting. IC Role / Device Role / Timing Role: Digitally managed VRM implementing SMBus/PMBus command set, including READ_VOUT, READ_IOUT, and MFR_READ_TEMPERATURE. Use Value: Provides certified VR13/VR14 telemetry accuracy (±4% current, ±0.5% voltage) and programmable fault responses required for platform validation. |
| High-Density FPGA Power System | Programmable Logic Board Management |
|
Use Scenario: Supplying multiple voltage domains (core, I/O, transceiver, auxiliary) on Xilinx Versal or Intel Agilex FPGAs with dynamic reconfiguration and partial rebit. IC Role / Device Role / Timing Role: Configurable quad-output regulator managing rail sequencing, voltage margining, and real-time current monitoring during bitstream loading and runtime reconfiguration. Use Value: Enables deterministic startup/shutdown sequences and per-rail current telemetry to prevent configuration failures due to undervoltage or overcurrent. |
Use Scenario: Integration into baseboard management controllers (BMCs) for telemetry-driven thermal/power management in Open Compute Project (OCP) servers. IC Role / Device Role / Timing Role: PMBus slave device providing telemetry data (uptime, peak currents, fault logs) to BMC via dual I²C buses for predictive maintenance and firmware updates. Use Value: Onboard EEPROM fault log and CRC-protected registers ensure traceable, tamper-resistant event history for compliance auditing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar digitally managed multi-phase power module applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTM4680EY#PBF | RoHS-compliant SAC305 finish; identical electrical specs and pinout; same 15mm × 22mm × 8.17mm BGA package. | Preferred for new designs targeting lead-free compliance; no functional difference in operation or configuration. | Select LTM4680EY#PBF when RoHS compliance is mandatory; LTM4681IY remains optimal for legacy SnPb assembly or mixed-technology boards. |
| LTM4686IY#PBF | Higher per-channel rating (40A vs 31.25A); adds dual-loop adaptive voltage positioning (AVP); same PMBus interface and BGA footprint. | Suitable for next-gen AI SoCs with higher current density; requires updated layout for increased copper and thermal vias. | Choose LTM4686IY#PBF only when >31.25A/channel is required; otherwise, LTM4681IY offers better cost/performance balance for mainstream FPGA/CPU applications. |
Compared with LTM4680EY#PBF, the LTM4681IY provides identical functionality with SnPb finish for legacy manufacturing compatibility; versus LTM4686IY#PBF, it trades peak current headroom for lower cost and proven thermal behavior in established 31.25A-per-rail systems.
Availability
LTM4681IY is available at Aetrix Electronics and suitable for AI accelerator core supply, multi-core CPU VR13/VR14 compliance, and high-density FPGA power systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LTM4681IY 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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, founded in 1965 and headquartered in Wilmington, MA.
The LTM4681IY belongs to Analog Devices' µModule regulator product line, engineered for high-density, digitally managed power delivery in space-constrained, thermally demanding applications such as datacenter accelerators and telecom infrastructure.
FAQ
What is the operating temperature range for the LTM4681IY?
The LTM4681IY is specified for an internal operating temperature range of –40°C to 125°C. Its thermal design includes bottom-side thermal pad conduction (θJCbottom = 1.4°C/W) and integrated temperature sensors (TSNS0–TSNS3) to support real-time derating. The device's thermal shutdown threshold is internally set and non-adjustable, ensuring safe operation under sustained overload conditions. All electrical specifications, including ±0.5% output voltage accuracy and ±4% current readback, are guaranteed across this full range.
Does the LTM4681IY support pin-strapping for startup configuration?
Yes, the LTM4681IY supports comprehensive pin-strapping for startup configuration without requiring PMBus communication. Dedicated resistor-configurable pins-including VOUTn_CFG, VTRIMn_CFG, FSWPH_nn_CFG, and ASEL_nn-allow setting initial output voltage (0.5V–3.3V), fine trim, switching frequency (250kHz–500kHz), channel phasing, and I²C slave address at power-on. This enables robust "first-power" operation in systems where host firmware initialization may be delayed or unavailable.
How does the LTM4681IY handle input current sensing?
The LTM4681IY integrates a precision input current sense amplifier per channel pair (IN_01± and IN_23±), supporting direct measurement of total input current with ±2% accuracy over 4.5V–16V. It digitizes sensed voltage differentials using its internal 16-bit ΔΣ ADC and reports results via PMBus READ_IIN command. No external shunt or op-amp is required, reducing BOM count and improving measurement consistency across temperature and load conditions.
Can multiple LTM4681IY modules be synchronized for higher current capacity?
Yes, the LTM4681IY supports PolyPhase load sharing and synchronization via SHARE_CLK_01/SHARE_CLK_23 pins. When multiple modules are connected in parallel, they can interleave switching phases to reduce input/output ripple, improve EMI, and distribute thermal load. Synchronization is achieved without external clock generators-modules automatically align phase angles based on shared clock edges and internal PLL locking, enabling seamless scaling to 250A+ with matched LTM4681IY units.
What telemetry data is readable from the LTM4681IY via PMBus?
The LTM4681IY provides comprehensive real-time telemetry via PMBus, including input/output voltages (READ_VIN, READ_VOUTn), input/output currents (READ_IIN, READ_IOUTn), temperatures (READ_TEMPERATUREn), uptime (READ_EIN), running peak values (READ_POUT_PEAK, READ_IOUT_PEAK), fault status (STATUS_WORD, STATUS_VOUT), and onboard EEPROM fault log records. All telemetry is sampled by the integrated 16-bit ΔΣ ADC and accessible at configurable polling rates up to 125Hz.
LTM4681IY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 330-BBGA Module
- Packaging:
- Tray
- Product Status:
- Active
- Type:
- -
- Number of Outputs:
- -
- Voltage - Input (Min):
- -
- Voltage - Input (Max):
- -
- Voltage - Output 1:
- -
- Voltage - Output 2:
- -
- Voltage - Output 3:
- -
- Voltage - Output 4:
- -
- Current - Output (Max):
- -
- Power (Watts):
- -
- Voltage - Isolation:
- -
- Applications:
- ITE (Commercial)
- Features:
- -
- Operating Temperature:
- -40°C ~ 125°C
- Efficiency:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 330-BGA (22x15)
- Control Features:
- -
- Approval Agency:
- -
- Standard Number:
- -
LTM4681IY FAQ
1.How can I place an order for LTM4681IY through Aetrix?
Please submit a Request for Quotation (RFQ) for LTM4681IY 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 LTM4681IY reliable?
The price and inventory of LTM4681IY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTM4681IY is usually 5 days.
3.What payment methods are accepted for LTM4681IY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTM4681IY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTM4681IY?
LTM4681IY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTM4681IY 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 LTM4681IY?
For technical support, including LTM4681IY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTM4681IY requirements.
6.How does Aetrix verify that LTM4681IY is sourced from the original manufacturer or authorized distributors?
All LTM4681IY 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 LTM4681IY meets industry standards.
7.What is the process for return or replacement of LTM4681IY?
All LTM4681IY units undergo pre-shipment inspection (PSI). If there is an issue with LTM4681IY, 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 LTM4681IY part is unused and in its original packaging.
Return procedure for LTM4681IY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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