LTM4628IV#PBF is a dual-channel, high-efficiency, ultrathin µModule® (power module) DC/DC step-down regulator designed and manufactured by Analog Devices Inc. (ADI) — originally developed by Linear Technology (acquired by ADI in 2017). It belongs to the advanced LTM46xx family of fully integrated, system-in-package power solutions, engineered specifically for space-constrained, high-performance applications, where delivering up to 13 A per channel (26 A total) from a single compact module — with exceptional thermal performance, fast transient response, and minimal external components — is critical.
The “IV” suffix denotes the 144-pin LGA package (16 mm × 16 mm × 1.82 mm) — an ultra-low-profile, thermally enhanced land-grid array; the “#PBF” signifies tray packaging, Pb-free (“PBF”), RoHS-compliant, and qualified for industrial temperature range (–40°C to +125°C junction).
⚠️ Critical Clarification:
The LTM4628 is not a controller IC or discrete power stage. It is a complete, self-contained dual-output power module, integrating:
- Two independent, synchronous buck regulators (each with internal MOSFETs, drivers, and gate logic);
- Precision analog control loop (voltage-mode, with programmable soft-start, tracking, and margining);
- High-density passive components (inductors, input/output capacitors, compensation network) — all embedded inside the package;
- Robust protection: overcurrent (OCP), overtemperature (OTP), undervoltage lockout (UVLO), and output overvoltage (OVP);
- Advanced digital features: I²C/PMBus™ interface (for real-time telemetry: VOUT, IOUT, TJ, faults), programmable sequencing, and fault logging.
It operates from an input voltage range of 4.5 V to 26.5 V, delivers two independently adjustable outputs from 0.6 V to 5 V, supports phase interleaving (reducing input ripple current by ～70%), and achieves up to 98% peak efficiency. Its 16 mm × 16 mm × 1.82 mm LGA footprint is less than half the area of two discrete 10 A modules — and its exposed metal top enables direct heatsinking (e.g., via thermal pad to chassis or cold plate), making it ideal for high-power density systems like AI accelerators, FPGAs, ASICs, and telecom infrastructure.
Introduction
The LTM4628IV#PBF delivers unprecedented power integration and intelligence in an ultrathin, thermally optimized package:
🔹 Dual 13 A outputs in one module: Eliminates need for two separate regulators, reducing PCB area by >40%, simplifying layout, and improving power delivery consistency (e.g., matched load sharing, timing, and thermal behavior);
🔹 True system-in-package: All magnetics (dual shielded inductors), MOSFETs, drivers, compensation, and filtering are fully embedded — only 4 external components required per channel (input cap, output cap, feedback resistors, optional I²C pull-ups);
🔹 Intelligent digital power management: Full PMBus 1.3 compliance enables remote configuration, real-time monitoring (voltage, current, temperature), fault logging, and adaptive margining — essential for data center power integrity and predictive maintenance;
🔹 Superior thermal performance: Exposed metal top (heat spreader) allows direct conduction cooling (e.g., 10 W/channel dissipation into a 25°C cold plate → TJ < 90°C), while bottom-side thermal vias support convection cooling — enabling full 13 A operation at +85°C ambient without airflow.
Its 144-pin LGA (IV) package (16 mm × 16 mm × 1.82 mm) is JEDEC-standard, reflow-compatible, and designed for automated optical inspection (AOI) — supporting high-yield, high-reliability volume manufacturing.
Key Features
✅ High-Power Dual Output:
• Output current: 13 A per channel (26 A total);
• Output voltage range: 0.6 V to 5.0 V (adjustable via resistor or I²C);
• Input voltage range: 4.5 V to 26.5 V;
• Peak efficiency: 98% @ 12 VIN, 1.0 VOUT, 13 A.
✅ Ultrathin, Thermally Optimized Package:
• Package: 144-pin LGA (16 mm × 16 mm × 1.82 mm);
• Exposed metal top: Enables direct heatsinking (conductive cooling);
• Bottom thermal vias: Support convection cooling — θJA ≈ 12°C/W (with 4-layer board, 2 oz Cu, 100 mm² EP copper);
• Operating junction temperature: –40°C to +125°C.
✅ Advanced Digital Control & Monitoring (PMBus):
• Interface: I²C-compatible PMBus 1.3 (400 kHz max);
• Real-time telemetry: VOUT, IOUT (per channel), TJ, input voltage, status flags;
• Programmable features: Soft-start, tracking, margining (±5%), sequencing, OCP/OVP/OTP thresholds;
• Fault logging: Stores last 8 fault events with timestamps and parameters.
✅ High Performance & Robustness:
• Transient response: < 50 µs recovery to ±1% for 50% load step (13 A → 6.5 A);
• Output voltage accuracy: ±0.5% (initial), ±1.0% (over line/temp/life);
• Protection: Overcurrent (hiccup or latch-off), overtemperature, input UVLO, output OVP;
• EMI reduction: Spread-spectrum modulation, phase interleaving, integrated shielding.
✅ Minimal External Components & Design Simplicity:
• Only 4 external components per channel required:
✓ Input capacitor (bulk + ceramic),
✓ Output capacitor (≥ 220 µF total per channel),
✓ Feedback resistors (if not using I²C),
✓ Optional I²C pull-ups;
• No external inductors, MOSFETs, drivers, or compensation needed.
Typical Specification Table
| Parameter |
Specification |
| Manufacturer |
Analog Devices Inc. (ADI) — formerly Linear Tech |
| Product Series |
LTM46xx Family (Ultrathin µModule Regulators) |
| Model |
LTM4628IV#PBF |
| Function |
Dual-Channel, 13 A per Channel µModule Regulator |
| Output Current (per ch) |
13 A (continuous), 15 A (peak) |
| Input Voltage Range |
4.5 V to 26.5 V |
| Output Voltage Range |
0.6 V to 5.0 V (adjustable) |
| Peak Efficiency |
98% @ 12 VIN, 1.0 VOUT, 13 A |
| Transient Response |
< 50 µs to ±1% (50% load step) |
| Output Accuracy |
±0.5% (initial), ±1.0% (over temp/line/life) |
| Interface |
PMBus 1.3 (I²C-compatible, 400 kHz) |
| Package |
144-Lead LGA (16 mm × 16 mm × 1.82 mm) (IV) |
| RoHS / Green |
Yes (Pb-free, Halogen-free) |
| Operating Junction Temp. |
–40°C to +125°C |
| Packaging |
Tray (#PBF) |
Typical Applications
🔹 AI & HPC Accelerators: Powering GPUs, TPUs, and FPGAs (e.g., NVIDIA A100, Xilinx Versal) requiring tightly regulated, high-current, low-noise 0.8–1.2 V rails — leveraging dual-channel interleaving and PMBus telemetry for dynamic voltage/frequency scaling (DVFS).
🔹 Telecom & Networking Equipment: Baseband units (BBUs), packet processors, and optical line cards needing reliable 3.3 V/5 V/12 V auxiliary rails with hot-swap capability and fault logging.
🔹 Test & Measurement Systems: High-speed ADC/DAC signal chains, arbitrary waveform generators, and spectrum analyzers — benefiting from low noise, fast transients, and precise voltage margining for calibration.
🔹 Industrial Automation & Robotics: Servo drives, vision systems, and PLCs requiring robust, compact power for multicore processors (e.g., AM6x Sitara, i.MX8) and high-speed I/O.
🔹 Aerospace & Defense Avionics: Ruggedized radar, EW, and comms modules where high power density, reliability, and thermal resilience (–40°C to +125°C) are mandatory.
🔹 Medical Imaging Electronics: CT detector modules, MRI gradient amplifiers, and ultrasound beamformers — enabled by low EMI, high efficiency, and PMBus-based health monitoring.
