Air Cooling Solutions

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.

iNERGY-Drive™ FOC 12V / 24V / 48V Up to 60,000 RPM Production-Ready PCB
Request Reference Design
Fan PQ Performance8080 · 48V
AMCA 210 Fig.12 · Type A · ρ 1.155 kg/m³
Static pressure (both)inergy powerCompetitor power
48.0 V2.49 A18,440 RPM
Static Pressure218.8 mmAq
Air Flow125.0 CFM
Input Power267 / 271 W
Power Saving+1.5 %
Operating PointQ = 125.0 CFM
Shut-offFree air
Same P-Q performance · inergy draws up to ~1.8% less power · 2026/04/22
AI Server Fan Solutions
iNERGY-Drive™ · 3-Phase High-Speed FOC

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
60K
Max RPM (4028 fan)
48V
Data Center Ready
11.6%
Efficiency vs Competitors
5°C
Lower Coil Temperature
IC Detail · Specifications
iU6398 · 48V HV-Buck 3-Phase FOC

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
iU6398 · Pin Assignment (Top View) — click to enlarge
ParameterValue
Max Voltage120V
Operating Voltage20V – 80V (VIN)
HV Buck100V internal Buck controller
Pre-driverN/N MOS pre-driver · Max 160V
VCC125.5V – 16V (pre-driver voltage)
Regulators5V VDD (logic)
Control InputPWM duty / DC voltage / Clock
ProtectionOCP / Current Chop / Current Limit / OLVP / Lock Protection and Auto-Recovery
Programming4-wire terminal (VDC/PWM/FG/GND)
PackageQFN 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
Reference Design Available — Schematic + BOM + Gerber + Firmware
VIN
GN
BTS
SW
CRS
VCC12
HV BUCK
LDO5V
FG
PWM
FG_Out
PWM_In
LDO
BLDC
FOC Controller
VBx
HOx
LSx
LOx
Level
Shifter
Delay
Match
GD
GD
N/N MOS
(U, V, W)
Motor
OPA
OPA
RC Gain
RC Gain
OCP
Hall(Option)
OPA1
OPA2
// iU6398 · 48V HV-Buck 3-phase FOC — functional block diagram ↔ scroll to explore
iU6395 · 12V 3-Phase FOC · N/N · New ★ Recommended

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
iU6395 · Pin Assignment (Top View) — click to enlarge
ParameterValue
Operating Voltage5V – 18V (22V abs. max)
Pre-driverN/N MOS pre-driver
Built-in Regulators8V VINT (pre-driver voltage) · 5V VDD (logic)
Control InputPWM duty / Clock
ProtectionOLVP / OCP / Current Limit / Current Chop / Lock Protection and Auto-Recovery
Programming4-wire terminal (VDC/PWM/FG/GND)
PackageQFN 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
Recommended for all new 12V 3-phase FOC fan designs
See Full FOC Performance Data →
PWM
PWM_In
BLDC
FOC Controller
VBx
HOx
LSx
LOx
Level
Shifter
Delay
Match
GD
GD
N/N MOS
(U, V, W)
Motor
OPA
OPA
RC Gain
RC Gain
OCP
Hall(Option)
OPA1
OPA2
PVCC
VDD(5V)
LDO8
PVCC 5~18V
VINT(8V)
LDO5
FGOUT
FG
UVLO
// iU6395 · 12V N/N 3-phase FOC — functional block diagram ↔ scroll to explore
iU6391 · 12V/24V 3-Phase FOC

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
iU6391 · Pin Assignment (Top View) — click to enlarge
ParameterValue
Operating Voltage7V – 32V (VM, FG)
Pre-driverP/N MOS pre-driver
Regulators7V VINT (pre-driver voltage) · 5V VDD (logic)
FG OutputOpen-drain MOSFET, programmable custom FG function
Control InputPWM duty / DC / Clock
ProtectionOCP / Current Chop / Current Limit / OLVP / Lock Protection and Auto-Recovery
Programming4-wire terminal (VDC/PWM/FG/GND)
PackageQFN 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
See Full FOC Performance Data →
VM
VCC
VDD(5V)
FGOUT
PWM
FG
PWM_In
LDO7
BLDC
FOC Controller
HOx
LOx
Level
Shifter
Delay
Match
GD
GD
N/P MOS
(U, V, W)
Motor
OPA
OPA
RC Gain
RC Gain
OCP
Hall(Option)
OPA1
OPA2
VM 7~32V
VINT(7V)
LDO5

(VM-Vint)
// iU6391 · 12V/24V 3-phase FOC — functional block diagram ↔ scroll to explore
iU6291 · Single-Phase BLDC · 7–32V

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
iU6291 · Pin Assignment (Top View) — click to enlarge
ParameterValue
TopologySingle-Phase BLDC Motor Controller
Operating Voltage7V – 32V (PVCC)
Pre-driverP/N MOS pre-driver
Regulators7V VINT (pre-driver voltage) · 5V VDD (logic)
FG OutputOpen-drain MOSFET, programmable custom FG function
Control InputPWM duty / DC / Clock
Lead AnglePositive / Negative / Zero-crossing
ProtectionOCP / Current Chop / Current Limit / OLVP / Lock Protection and Auto-Recovery
Programming4-wire terminal (VDC/PWM/FG/GND)
PackageQFN-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
Request iU6291 Reference Design →
VM
VCC
VDD(5V)
FGOUT
PWM
FG
PWM_In
LDO7
BLDC
Smart Single Phase
Controller
HOx
LOx
Level
Shifter
Delay
Match
GD
GD
Motor
CMP
OCP
Hall(Option)
VM 7~32V
VINT(7V)
LDO5

(VM-Vint)
// iU6291 · Single-Phase BLDC controller — functional block diagram ↔ scroll to explore
Air-Cooling Design-In Map

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 TypeCommon Fan SizeVoltageNotesRecommended IC
1U Server402812V / 24VIndustry-standard 40×40×28 mm high-speed faniU6395 iU6391
1U High-Performance AI Server405612V / 24V / 48VDual-rotor, very high static pressureiU6398 iU6395
2U Server603812V / 24V / 48VCommon CPU and chassis coolingiU6398 iU6395
2U High Density605624V / 48VDual-rotor server faniU6398
3U / 4U Server803812V / 24V / 48VVery common telecom and server faniU6398 iU6391
AI GPU Server8056 / 807648VExtreme airflow, counter-rotating fansiU6398
Storage Server923812V / 24V / 48VHigh airflow, lower noiseiU6398 iU6395
Telecom Rack1203848VWidely used in outdoor telecom cabinetsiU6398
Datacenter Cooling Module1207648VHigh-pressure cooling for datacenter infrastructureiU6398
Edge Server / OCP Platform1405148VOpen Compute and edge computing systemsiU6398
BESS Cooling System1725148VBattery Energy Storage System coolingiU6398
Large Industrial Cooling20060 / 2008048VPower conversion and industrial cabinet coolingiU6398
AI Rack Cooling22060 / 2258048VHigh-volume airflow applicationsiU6398
CDU / Liquid Cooling Support2508048VCooling Distribution Unit air moversiU6398
Hyperscale Datacenter Cooling28080 / 3008048VRack-level and facility-level cooling systemsiU6398
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 ClassCommon Fan SizeVoltageRecommended IC
Entry GPU4010, 401512ViU6395 iU6291
Mid-range GPU5010, 501512ViU6395 iU6291
Gaming GPU7010, 701512ViU6395 iU6391
RTX 4070–5080 Class8010, 8015, 901512ViU6395 iU6391
AI GPU Blower7530, 9733, custom12ViU6395 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.

Consumer / VGA
12V · 4010 / 5015 / 7015 / 8015
High-volume consumer GPU and AI accelerator cooling fans on the 12V rail.
iU6395iU6291
Enterprise / Server
12V/24V · 4028 / 6038 / 8038
The workhorse server fans across enterprise, 1U–4U and telecom chassis.
iU6395iU6391iU6398
Emerging AI Server
48V · 4056 / 6056 / 8056
Dual-rotor 48V architectures for high-performance AI and GPU servers.
iU6398
Storage & Telecom
48V · 9238 / 12038 / 12076
High-airflow storage servers and outdoor telecom cabinet cooling.
iU6398
Edge / OCP / BESS
48V · 14051 / 17251
Open Compute edge platforms and Battery Energy Storage System cooling.
iU6398
Industrial & AI Rack
48V · 20060 / 20080 / 22060 / 22580
High-power industrial cabinet and high-volume AI rack airflow.
iU6398
CDU & Hyperscale
48V · 25080 / 28080 / 30080
Cooling Distribution Unit air movers and facility-level hyperscale cooling.
iU6398
Reference Designs

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.

Reference Design · 48V FOC Platform
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 → 20080iU6398 + iM164148V
Request Files →
Reference Design · 12V N/N FOC · New ★
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.
iU6395 QFN28N/N Stage12V
Request Files →
Reference Design · 12/24V FOC
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.
iU6391 QFN28Hall Optional12/24V
Request Files →
Reference Design · Single-Phase
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.
iU6291 QFN20Hall Support12/24V
Request Files →
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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.

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