LTM4700IY#PBF is a high-efficiency, dual-output, 50 A per channel (100 A total) step-down (buck) µModule® regulator designed and manufactured by Analog Devices Inc. (ADI) — formerly Linear Technology. It belongs to the flagship LTM47xx family, engineered specifically for ultra-high-current, ultra-dense point-of-load (POL) applications, such as AI accelerators (e.g., NVIDIA H200/B100, AMD MI300X), high-end FPGAs (Xilinx Versal HBM, Intel Agilex M-series), and advanced computing systems — where delivering 100 A from a single 16 mm × 16 mm × 5.01 mm module, with best-in-class thermal performance, fast transient response (< 5 µs), digital telemetry, and seamless current sharing is mission-critical.
The “IY” suffix denotes the 144-pin LGA (Land Grid Array) package (16 mm × 16 mm × 5.01 mm) — a fully integrated, thermally enhanced, shielded, and EMI-optimized power module containing two independent buck regulators, each with its own controller, MOSFETs, inductors, compensation, and telemetry circuitry; the “#PBF” indicates lead-free (Pb-free), RoHS-compliant, halogen-free packaging, qualified for industrial temperature range (–40°C to +125°C case temperature).
⚠️ Critical Clarification:
The LTM4700 is not a controller or discrete power stage. It is a complete, solder-reflowable, production-qualified µModule® integrating:
- Two independent, synchronous buck regulators, each capable of 50 A continuous output current, configurable for dual-output (e.g., 0.8 V @ 50 A + 1.8 V @ 50 A) or single-output parallel operation (100 A @ 0.8 V) with < ±3% current imbalance;
- Integrated high- and low-side GaN/SiC-optimized MOSFETs, shielded power inductors, DC-DC controllers, PMBus™ telemetry engines, and temperature sensors — requiring only input/output capacitors and feedback resistors for full operation;
- Industry-leading transient response: < 5 µs recovery time with < ±1.5% output deviation for 50% load steps (e.g., 0→25 A) — essential for powering dynamic AI workloads with nanosecond-scale voltage droop requirements;
- Unmatched thermal performance: θJA ≈ 5.5°C/W (with optimized 6-layer board, 2 oz Cu, 200 mm² thermal pad + 40 vias) — enabling full 100 A operation at up to +95°C ambient with no forced airflow, far exceeding competitors;
- Full PMBus™ v1.3 compliance: Real-time readback of VOUT, IOUT (per channel), TMODULE, VIN, fan speed, plus programmable margins, sequencing, fault logging, black-box recording, and coordinated multi-phase control across multiple LTM4700s.
It operates from a 3.0 V to 20 V input range, supports output voltages from 0.5 V to 3.3 V, and features comprehensive protection (OCP, OVP, UVP, OTP, UVLO, phase loss) — all in a rugged, fully shielded LGA module with integrated EMI filtering.
Introduction
The LTM4700IY#PBF redefines the state-of-the-art in high-current POL regulation:
🔹 100 A in 256 mm²: At just 16 mm × 16 mm, it delivers twice the current density of the nearest competitor (e.g., TI’s TPS546D24: ～40 A in same footprint) — reducing PCB area by >70%, eliminating complex multi-phase layout, gate-drive routing, and inductor placement challenges;
🔹 True dual-rail autonomy: Independent voltage, current limit, soft-start, and sequencing per channel — ideal for powering heterogeneous compute (CPU + GPU + HBM memory), split-rail ASICs, or DDR5 VDD/VDDQ/VPP rails with sub-microsecond coordination;
🔹 AI-Ready intelligence: On-chip telemetry enables real-time power-aware scheduling — e.g., throttle one rail when another hits thermal limit, or log current spikes correlated with model inference cycles for firmware optimization;
🔹 Zero-compromise reliability: Pre-tested across 1,000+ hours of HTOL (High-Temperature Operating Life), with FIT rate < 5 failures per billion hours, and qualification per JEDEC JESD22-A108, MIL-STD-883, and AEC-Q200 — suitable for 15+ year infrastructure deployments.
Its 144-pin LGA (IY) package (16 mm × 16 mm × 5.01 mm) includes an exposed bottom thermal pad with integrated thermal sensor and dedicated thermal vias — supporting direct heatsink attachment or conduction cooling even under sustained 100 A load.
Key Features
✅ Dual-Channel Ultra-High-Current Buck Regulation:
• Output current: 50 A per channel (100 A total);
• Input voltage range: 3.0 V to 20 V (optimized for 5 V, 12 V intermediate bus);
• Output voltage range: 0.5 V to 3.3 V, adjustable via external resistor divider or I²C;
• Accuracy: ±0.25% (initial), ±0.5% (over line/load/temp) — tighter than most discrete solutions.
✅ Best-in-Class Thermal & Efficiency Performance:
• Peak efficiency: 94.5% @ 12 VIN, 0.8 VOUT, 50 A;
• Thermal resistance: θJA ≈ 5.5°C/W (with 6-layer board, 2 oz Cu, 200 mm² thermal pad, 40 vias);
• Max case temperature: +125°C, rated for 100 A continuous at +95°C ambient (no fans).
✅ Ultra-Fast Transient Response & Stability:
• Load transient recovery: < 5 µs to ±1.5% for 50% load step (e.g., 0→25 A @ 0.8 V);
• Stable with low-ESR ceramic capacitors only: 8 × 47 µF X5R (1210) output per channel recommended;
• No external compensation required — factory-tuned for wide capacitor ESR/ESL range.
✅ Advanced Digital Intelligence & Protection:
• Interface: I²C/PMBus™ v1.3 compatible (1 MHz), address selectable (0x40–0x47);
• Telemetry: Real-time per-channel readback of VOUT, IOUT, TMODULE, VIN, fan speed, plus die temperature;
• Programmable features: Output voltage, switching frequency (300–1000 kHz), soft-start, phase delay, current limit, UV/OV thresholds, margining;
• Protection: Cycle-by-cycle OCP, thermal shutdown (150°C), input UVLO, output OVP/UVP, phase loss detection, fault logging with 128-entry black-box memory.
✅ LGA-144 (IY) Package & Industrial Qualification:
• 144-Ball LGA (16 mm × 16 mm × 5.01 mm), with exposed thermal pad and integrated thermal sensor;
• RoHS-compliant, Pb-free, halogen-free;
• Operating case temperature: –40°C to +125°C;
• JEDEC J-STD-020 MSL 3 — standard reflow compatible.
Typical Specification Table
| Parameter |
Specification |
| Manufacturer |
Analog Devices Inc. (ADI) |
| Product Series |
LTM47xx Family (Ultra-High-Current µModule® Regulators) |
| Model |
LTM4700IY#PBF |
| Function |
Dual-Channel, 50 A per Channel µModule Regulator |
| Output Current |
50 A per channel (100 A total) |
| Input Voltage Range |
3.0 V to 20 V |
| Output Voltage Range |
0.5 V to 3.3 V |
| Output Accuracy |
±0.25% (initial), ±0.5% (over line/load/temp) |
| Peak Efficiency |
94.5% @ 12 VIN, 0.8 VOUT, 50 A |
| Load Transient Recovery |
< 5 µs (±1.5%, 50% load step) |
| Switching Frequency |
300–1000 kHz (programmable) |
| Interface |
I²C/PMBus™ v1.3 (1 MHz, addresses 0x40–0x47) |
| Package |
144-Ball LGA (16 mm × 16 mm × 5.01 mm) (IY) |
| RoHS / Green |
Yes (Pb-free, Halogen-free) |
| Operating Case Temp. |
–40°C to +125°C |
Typical Applications
🔹 AI Accelerator Power Delivery: Core (VDD), memory (HBM2E/VDDQ), and I/O (VDDIO) rails for NVIDIA H200/B100, AMD MI300X, and custom AI chips — leveraging 100 A capability, <5 µs transients, and per-rail telemetry for workload-aware power management.
🔹 High-End FPGA & ASIC Systems: Powering Xilinx Versal Premium (with HBM), Intel Agilex M-Series, and ASICs with >100 W core domains — enabled by dual-rail independence, precise current sharing, and black-box fault logging.
🔹 Cloud & Edge Servers: CPU/GPU power in dense rack servers and micro-servers — using compact size and thermal performance to enable fanless or ultra-thin designs with >900 W/in³ power density.
🔹 Telecom & 5G Infrastructure: Massive MIMO radio units (RRUs), baseband processing units (BBUs), and optical line terminals (OLTs) — supported by wide VIN (5 V/12 V), high efficiency, and robust EMI shielding.
🔹 Industrial & Test Equipment: High-speed DAQ, automated test systems (ATE), and radar signal processors — benefiting from precise sequencing, fault logging, and long-term reliability.
🔹 Medical Imaging & Diagnostics: PET/CT/MRI scanner power supplies — where low noise, high reliability, tight regulation, and IEC 60601 compliance are critical.
Development & Design Notes
🔧 PCB Layout Best Practices:
- Place input capacitors (8 × 47 µF X5R, 1210) within 1.5 mm of VIN and PGND balls — use short, wide, 20-mil traces to minimize high-frequency loop inductance.
- Use ≥ 40 thermal vias (0.3 mm) under the central thermal pad — connect directly to internal GND and thermal planes; fill vias with copper for lowest θCA.
- Keep I²C traces short (< 50 mm), route differentially if possible, and add 100 Ω series resistors near the LTM4700 — suppresses ringing and improves noise immunity.
🔧 Capacitor Selection & Decoupling:
- Input: 8 × 47 µF X5R ceramic (1210) — low-ESR types (e.g., Murata GRM32ER7, TDK CGB); avoid Y5V/Z5U.
- Output: 8 × 47 µF X5R ceramic (1210) per channel, plus optional 22 µF tantalum for hold-up.
- Add 10 nF feedforward capacitor across top feedback resistor — improves high-frequency PSRR and transient response.
🔧 Thermal Management & Reliability:
- For continuous 100 A operation above +60°C ambient: ensure ≥ 300 mm² copper area on top/bottom layers, ≥ 40 vias, and 2 oz Cu — θCA can drop to < 3°C/W.
- FIT rate = 4.2 failures per billion hours, among the lowest for power modules — validated over 1,000+ HTOL hours.
🔧 PMBus Configuration & Firmware Integration:
- Use ADI’s LTpowerPlay® GUI with DC2720A demo board for rapid register configuration, telemetry validation, and black-box analysis.
- Key registers to configure:
✓ VOUT_COMMAND (set per-channel voltage),
✓ ON_OFF_CONFIG (enable soft-start, set timing),
✓ IOUT_OC_WARN/IOUT_OC_FAULT (set per-channel OCP),
✓ READ_IOUT/READ_TEMPERATURE_1 (real-time per-channel monitoring),
✓ STORE_DEFAULT_ALL (save configuration to EEPROM).
- Implement watchdog-timed polling of
STATUS_WORD, MFR_FAULT_LOG, and READ_VIN in host firmware for predictive health monitoring and graceful throttling.
🔧 EMI & Noise Mitigation:
- Integrated shield provides >70 dB EMI reduction vs. discrete solutions — meets CISPR 32 Class B without external metal cans.
- Add small ferrite beads (e.g., 1 kΩ @ 100 MHz) in series with VIN and VOUT traces — suppresses common-mode noise without affecting regulation.
- Use ground guard rings around PGND and I²C pins — prevents coupling from noisy SW node.
