The ISL9440, ISL9440A and ISL9441 are quad-output synchronous buck controllers that integrate 3 PWM controllers and 1 low drop-out linear regulator controller, which are full featured and designed to provide multi-rail power for use in products such as cable and satellite set-top boxes, VoIP gateways, cable modems, and other home connectivity products as well as a variety of industrial and general purpose applications. Each output is adjustable down to 0. 8V. The PWMs are synchronized at 180° out of phase thus reducing the RMS input current and ripple voltage. The ISL9440, ISL9440A and ISL9441 offer internal soft-start, independent enable inputs for ease of supply rail sequencing, and integrated UV/OV/OC/OT protections in a space conscious 5mmx5mm QFN package. The ISL9440 and ISL9440A offers an early warning function to output a logic signal to warn the system to back up data when the input voltage falls below a certain level. The ISL9440, ISL9440A and ISL9441 are utilize internal loop compensation to keep minimum peripheral components for compact design and a low total solution cost. These devices are implemented with current mode control with feed forward to cover various applications even with fixed internal compensations. The table below shows the difference in terms of ISL9440, ISL9440A and ISL9441 features.

ISL9440 YES 300
ISL9440A YES 600
ISL9441 NO 300


  • Three integrated synchronous buck PWM controllers
  • Internal bootstrap diodes
  • Internal compensation
  • Internal soft-start
  • Independent control for each regulator and programmable output voltages; independent enable/shutdown
  • Fixed Switching Frequency: 300kHz (ISL9440, ISL9441); 600kHz (ISL9440A)
  • Adaptive shoot through protection on all synchronous buck controllers
  • Independently programmable voltage outputs
  • Out-of-phase switching to reduce input capacitance (0°/180°/0°)
  • No external current sense resistor
  • Uses lower MOSFET's rDS(ON)
  • Current mode controller with voltage feed forward
  • Complete protection
  • Overcurrent, overvoltage, undervoltage lockout, over-temperature
  • Cycle-by-cycle current limiting
  • Wide input voltage range
  • Input rail powers VIN Pin: 5.6V to 24V
  • Input rail powers VCC_5V Pin (VIN tied to VCC_5V, for 5V input applications): 4.5V to 5.6V
  • Early warning (ISL9440, ISL9440A) on input voltage failure
  • Integrated reset function (ISL9440, ISL9440A)
  • Pb-free (RoHS compliant)


  • Satellite and Cable Set-Top Boxes
  • Cable Modems
  • VoX Gateway Devices
  • NAS/SAN Devices

Product Options

Part Number Part Status Pkg. Type Carrier Type MOQ Buy Sample
Active QFN Tube 60
Active QFN Reel 6000

Documentation & Downloads

Title language Type Format File Size Date
Datasheets & Errata
ISL9440, ISL9440A, ISL9441 Datasheet 日本語 Datasheet PDF 1.52 MB
User Guides & Manuals
ISL9440AEVAL1Z User Guide Manual PDF 1.32 MB
ISL9440AMGTHEVAL1Z User Guide Manual PDF 926 KB
Application Notes & White Papers
Five Easy Steps to Create a Multi-Load Power Solution White Paper PDF 846 KB
How Green is Your Cloud? White Paper PDF 295 KB
AN1681: Grounding Techniques Application Note PDF 509 KB
AN1684: Nonideality of Ground Application Note PDF 397 KB
PCN15046 - Wafer Fabrication Site Change for Listed Intersil Products - Global Foundry P6 Process transfer to Palm Bay - Phase II Product Change Notice PDF 398 KB
PCN13060 - Test Site Change for the Listed Intersil Products Product Change Notice PDF 223 KB
PCN13025 - Alternate Bond Wire Material and Manufacturing Facilities for Assembly of the Listed Intersil DFN/QFN Packaged Products - Advanced Semiconductor Engineering (ASECL) - Chung-Li , Taiwan and STATS ChipPAC (SCM) - Kuala Lumpur, Mal Product Change Notice PDF 106 KB
PCN13009 - Alternate Bond Wire Material and Manufacturing Facilities for Assembly of the Listed Intersil DFN/QFN Packaged Products - Advanced Semiconductor Engineering (ASECL) - Chung-Li (ASECL), Taiwan and STATS ChipPAC (SCM) - Kuala Lump Product Change Notice PDF 173 KB
PCN10055 - Alternate Bond Wire Material for Assembly of the Listed Intersil DFN/QFN Packaged Products - STATS ChipPAC Malaysia Product Change Notice PDF 248 KB
ISL9440xEVAL1Z Design Files Design File ZIP 274 KB
ISL9440 Dual Sync Buck with Linear Reg iSim:PE Model Schematic SXSCH 250 KB
TB389: PCB Land Pattern Design and Surface Mount Guidelines for QFN Packages Other PDF 958 KB

Software & Tool Pages

Title Type Description Company
iSim:PE Offline Simulation Tool Simulator iSim Personal Edition (iSim:PE) speeds the design cycle and reduces risk early in any project, identifying parts that can be used in current as well as next-generation designs. Renesas

Boards & Kits

Part Number Title Type Company
ISL9440AEVAL1Z Triple, 180° Out-of-Phase, Step-Down PWM and Single Linear Controller Evaluation Board Evaluation Renesas