AI Server Fan BLDC Motor Driver ICs
Intelligent. Efficient. Scalable. High-performance fan solutions for AI servers and data centers — powerful airflow, high efficiency, low vibration and high adaptability, and complete reference designs.
Intelligent. Efficient. Scalable.
Designed specifically for AI servers and data centers, our inergy-Drive™ fan solutions deliver powerful airflow, ultra-low vibration and exceptional energy savings to keep AI systems running at peak reliability 24/7.
- Up to 60,000 RPM — validated on 4028 server fan format
- FOC Precision Control — low vibration, high efficiency, self-learning algorithm
- System-Level Optimization — thermal-aware, energy-saving control platform
- Total Solution — Driver IC + MCU firmware + reference schematic ready
- 4-Wire Terminal Programming — flash parameters without disassembling the fan
- OEM/ODM Support — customizable for your specific fan and application
iU6398 — 48V Server Fan Driver
The go-to solution for 48V AI data center fans and liquid cooling pumps. Integrates a 100V Buck controller to eliminate the thermal limitation of external step-down circuits.
iU6398 Datasheet PDF · Rev 0.1| Parameter | Value |
|---|---|
| Max Voltage | 120V |
| Operating Voltage | 20V – 80V (VIN) |
| HV Buck | 100V internal Buck controller |
| Pre-driver | N/N MOS pre-driver · Max 160V |
| VCC12 | 5.5V – 16V (pre-driver voltage) |
| Regulators | 5V VDD (logic) |
| Control Input | PWM duty / DC voltage / Clock |
| Protection | OCP / Current Chop / Current Limit / OLVP / Lock Protection and Auto-Recovery |
| Programming | 4-wire terminal (VDC/PWM/FG/GND) |
| Package | QFN 4×4 – 32L |
- HV Buck integrated — no external step-down, eliminates thermal bottleneck in 48V fan PCBA
- 160V N/N pre-driver — direct drive of high-voltage N-channel MOSFETs
- Internal temperature sensor — real-time OTP protection without external NTC
- FOC self-learning — auto-optimizes across load and coil variation
- PWM / DC / Clock input — compatible with all BMC/IPMI fan control interfaces
- QFN 4×4-32L — compact package, fits 40mm fan PCB form factor
Application: 48V AI Server Fan
4028 / 4056 server fan · 48V 1A FOC design · PCBA diameter 24.4mm
iU6395 — New 12V FOC Controller Recommended over iU6391
The newest member of the inergy-Drive™ family and the recommended choice for new 12V-class server and VGA fan designs. The iU6395 moves to an N/N MOS pre-driver with dual integrated current-sense amplifiers, giving a cooler, higher-current power stage and tighter FOC current control than the established iU6391.
iU6395 Datasheet PDF · Rev P0.1| Parameter | Value |
|---|---|
| Operating Voltage | 5V – 18V (22V abs. max) |
| Pre-driver | N/N MOS pre-driver |
| Built-in Regulators | 8V VINT (pre-driver voltage) · 5V VDD (logic) |
| Control Input | PWM duty / Clock |
| Protection | OLVP / OCP / Current Limit / Current Chop / Lock Protection and Auto-Recovery |
| Programming | 4-wire terminal (VDC/PWM/FG/GND) |
| Package | QFN 4×4 – 28L |
Why iU6395 over iU6391
- N/N MOS pre-driver — drives low-RDS(on) N-channel MOSFETs on both high and low side for higher current and a cooler power stage than the N/P stage of iU6391
- Dual integrated current-sense amplifiers — two on-chip current amps plus two op-amps give precise phase-current sensing for FOC, removing external current-sense circuitry
- Dedicated 8V VINT gate-drive rail — strong, stable gate drive independent of the motor supply
- Internal + external thermal sensor — place OTP sensing at the hottest point of the fan PCBA
- Windmill startup — catches a fan already spinning (forward or reverse) before taking control
- Drop-in tooling — same QFN 4×4-28L footprint and 4-wire terminal programming as iU6391
Application: 12V High-Current Server & VGA Fans
4028 / 4056 server fans · 4010 / 5015 / 7015 / 8015 VGA fans · high-current N/N power stage
iU6391 — 12V/24V Fan Controller
Three-phase high-speed FOC driver with built-in N/P pre-driver covering the wider 7–32V (12V/24V) range. The established, proven IC for 12V and 24V server fans — for new high-current 12V designs, the iU6395 is now recommended.
iU6391 Datasheet PDF · Rev 0.2| Parameter | Value |
|---|---|
| Operating Voltage | 7V – 32V (VM, FG) |
| Pre-driver | P/N MOS pre-driver |
| Regulators | 7V VINT (pre-driver voltage) · 5V VDD (logic) |
| FG Output | Open-drain MOSFET, programmable custom FG function |
| Control Input | PWM duty / DC / Clock |
| Protection | OCP / Current Chop / Current Limit / OLVP / Lock Protection and Auto-Recovery |
| Programming | 4-wire terminal (VDC/PWM/FG/GND) |
| Package | QFN 4×4 – 28L |
- FOC vs 120° square wave — better efficiency at 7,000–20,000 RPM (sine magnetization) and 8,000–22,000 RPM (square magnetization)
- Auto-optimize across all loads — light, medium, and heavy fan loads
- ±15% coil tolerance — auto-corrects, IDC increase only 1.7–5.8%
- 120,000 RPM capability — 4KHz electrical frequency × 4-pole motor
- All startup conditions — zero speed, tailwind, reverse wind
- Constant power & current — maintains set operating point across voltage variation
iU6291 — Single-Phase Fan Driver
Single-phase BLDC motor controller with an embedded P/N MOS pre-driver and integrated peripherals across a 7–32V supply. CMOS-compatible logic, flexible motor-parameter tuning, complete OCP / OVP / UVLO protection, and validated at ultra-high speed 45000 RPM on a 12V 4028 fan.
iU6291 Datasheet PDF · Rev 0.2| Parameter | Value |
|---|---|
| Topology | Single-Phase BLDC Motor Controller |
| Operating Voltage | 7V – 32V (PVCC) |
| Pre-driver | P/N MOS pre-driver |
| Regulators | 7V VINT (pre-driver voltage) · 5V VDD (logic) |
| FG Output | Open-drain MOSFET, programmable custom FG function |
| Control Input | PWM duty / DC / Clock |
| Lead Angle | Positive / Negative / Zero-crossing |
| Protection | OCP / Current Chop / Current Limit / OLVP / Lock Protection and Auto-Recovery |
| Programming | 4-wire terminal (VDC/PWM/FG/GND) |
| Package | QFN-20 (4×4 mm) |
- Quasi-sine waveform control — rectangular / trapezoidal waveform generation softens switching, cutting commutation noise and vibration
- Ultra-high speed 45000 RPM validated — 12V single-phase 4028 fan (FG × 30 = RPM)
- Lead-angle adjustment — positive / negative / zero-crossing to optimize efficiency
- Constant power — current auto-adjusts with voltage (10V×1.23A ≈ 12V×1.02A ≈ 14.2V×0.865A ≈ 12.3W)
- +3.3–11.6% efficiency vs competitor — lower IDC across all PWM levels; coil temp ~5°C cooler after 60 min
- 4-wire terminal programming — flash via VDC / PWM / FG / GND without disassembly
- Complete protection — OCP / OVP / UVLO with programmable locked-rotor & soft-start
Fan Size & Voltage Application Map
inergy cooling-fan controllers are dedicated to the fan formats and voltage rails used across today's AI datacenter, server, telecom and GPU systems. Use this map to match the right inergy-Drive™ IC to your fan size and rail.
Server & Datacenter Fans
| Server Type | Common Fan Size | Voltage | Notes | Recommended IC |
|---|---|---|---|---|
| 1U Server | 4028 | 12V / 24V | Industry-standard 40×40×28 mm high-speed fan | iU6395 iU6391 |
| 1U High-Performance AI Server | 4056 | 12V / 24V / 48V | Dual-rotor, very high static pressure | iU6398 iU6395 |
| 2U Server | 6038 | 12V / 24V / 48V | Common CPU and chassis cooling | iU6398 iU6395 |
| 2U High Density | 6056 | 24V / 48V | Dual-rotor server fan | iU6398 |
| 3U / 4U Server | 8038 | 12V / 24V / 48V | Very common telecom and server fan | iU6398 iU6391 |
| AI GPU Server | 8056 / 8076 | 48V | Extreme airflow, counter-rotating fans | iU6398 |
| Storage Server | 9238 | 12V / 24V / 48V | High airflow, lower noise | iU6398 iU6395 |
| Telecom Rack | 12038 | 48V | Widely used in outdoor telecom cabinets | iU6398 |
| Datacenter Cooling Module | 12076 | 48V | High-pressure cooling for datacenter infrastructure | iU6398 |
| Edge Server / OCP Platform | 14051 | 48V | Open Compute and edge computing systems | iU6398 |
| BESS Cooling System | 17251 | 48V | Battery Energy Storage System cooling | iU6398 |
| Large Industrial Cooling | 20060 / 20080 | 48V | Power conversion and industrial cabinet cooling | iU6398 |
| AI Rack Cooling | 22060 / 22580 | 48V | High-volume airflow applications | iU6398 |
| CDU / Liquid Cooling Support | 25080 | 48V | Cooling Distribution Unit air movers | iU6398 |
| Hyperscale Datacenter Cooling | 28080 / 30080 | 48V | Rack-level and facility-level cooling systems | iU6398 |
Accelerate Your Next-Generation Cooling Design with the iU6398 Platform
From compact 40×56 mm server fans to high-power 200 mm+ EC cooling solutions, the iU6398 delivers a highly integrated 48V BLDC motor-driver platform for AI servers, telecom infrastructure, datacenters, battery energy storage systems (BESS), and industrial cooling applications.
Designed for demanding thermal-management environments, the iU6398 provides advanced PWM speed control, FG / RD monitoring, locked-rotor protection, and high-efficiency motor control — helping manufacturers reduce development time while maximizing cooling performance and system reliability.
Whether you are developing high-speed server fans, AI GPU cooling modules, telecom cooling systems, or large EC fans for energy storage and datacenter infrastructure, the iU6398 offers a scalable solution to accelerate your product development.
Evaluate the iU6398 with Our Engineering Team →Traditional Servers — 12V
Mainstream rail for general-purpose server fans. iU6395 (N/N) recommended for new high-current designs.
Telecom Equipment — 24V
Established telecom and industrial fan rail, covered by iU6391 across the 7–32V range.
AI Servers / OCP / Datacenter — 48V
Increasingly common (2025–2026) for lower current and better power efficiency. iU6398 HV-Buck is purpose-built for it.
VGA / GPU Fans — mostly 12V BLDC
| GPU Class | Common Fan Size | Voltage | Recommended IC |
|---|---|---|---|
| Entry GPU | 4010, 4015 | 12V | iU6395 iU6291 |
| Mid-range GPU | 5010, 5015 | 12V | iU6395 iU6291 |
| Gaming GPU | 7010, 7015 | 12V | iU6395 iU6391 |
| RTX 4070–5080 Class | 8010, 8015, 9015 | 12V | iU6395 iU6391 |
| AI GPU Blower | 7530, 9733, custom | 12V | iU6395 iU6291 |
Today's leading graphics cards use custom versions of these sizes with 12V motors and integrated FG / PWM control — a direct fit for the inergy-Drive™ lineup. The new iU6395 three-phase FOC controller and the iU6291 single-phase driver deliver the low acoustic noise, high efficiency, and precise speed control that premium GPU and AI accelerator cooling demands, with production-ready reference designs to shorten time-to-market.
inergy Cooling-Fan ASIC Roadmap Priorities
From consumer GPU fans to hyperscale datacenter EC fans, the inergy-Drive™ lineup spans the full cooling-fan opportunity — 40 mm all the way up to 300 mm-class air movers.
12V · 4010 / 5015 / 7015 / 8015
High-volume consumer GPU and AI accelerator cooling fans on the 12V rail.
12V/24V · 4028 / 6038 / 8038
The workhorse server fans across enterprise, 1U–4U and telecom chassis.
48V · 4056 / 6056 / 8056
Dual-rotor 48V architectures for high-performance AI and GPU servers.
48V · 9238 / 12038 / 12076
High-airflow storage servers and outdoor telecom cabinet cooling.
48V · 14051 / 17251
Open Compute edge platforms and Battery Energy Storage System cooling.
48V · 20060 / 20080 / 22060 / 22580
High-power industrial cabinet and high-volume AI rack airflow.
48V · 25080 / 28080 / 30080
Cooling Distribution Unit air movers and facility-level hyperscale cooling.
Production-Ready Reference Designs
Production-ready PCB reference designs for AI server, datacenter and GPU fan applications. The iU6398 48V platform alone scales from compact 4028 server fans all the way up to 200 mm-class (20080) high-power EC air movers — and every design ships with schematic, BOM, Gerber files and C-source firmware, ready for mass production.
48V FOC — 4028 up to 20080
One scalable 48V BLDC reference platform spanning compact 4028 server fans to 200 mm-class (20080) high-power EC fans. iU6398 HV-Buck + iM-series MOSFETs, Buck-integrated with no external regulator. Reference PCBA from 24.4 mm upward, validated across server, telecom, BESS and datacenter cooling.
4028 12V 3-Phase FOC (iU6395)
EVB for the new iU6395 N/N FOC controller. Low-RDS(on) N-channel power stage with dual integrated current sensing. Recommended platform for new high-current 12V server and VGA fans. QFN-28, Hall optional.
4028 12V/24V 3-Phase FOC (iU6391)
EVB PCB for iU6391 three-phase FOC. 28-pin QFN with N/P MOSFET power stage. Hall sensor optional. Production-ready schematic and BOM included.
Single-Phase High-Speed (iU6291)
iU6291 1P EVB (PCB-P-T271 V.02). Red PCB with Hall sensor option. Supports 12V/24V single-phase fan up to 60,000 RPM. S Programmer compatible.
Request Air Cooling Reference Design Files
Schematic + BOM + Gerber + C-source firmware. Our FAE will match the right IC to your fan spec and arrange remote fine-tune support.