ISL85003: Highly Efficient 3A Synchronous Buck Regulator

The ISL85003 and ISL85003A are synchronous buck regulators with integrated high-side and low-side FETs. The regulator can operate from an input voltage range of 4.5V to 18V while delivering a very efficient continuous 3A current. This is all delivered in a very compact 3mmx4mm DFN package.

The ISL85003 is designed on Intersil’s proprietary fab process that is designed to deliver very low rDS(ON) FETs with an optimized current mode controller wrapped around it. The high-side NFET is designed to have an rDS(ON) of 65mΩ while the low-side NFET is designed to have an rDS(ON) of 45mΩ. With these two FETs, the device delivers very high efficiency power to the load.

The ISL85003 can automatically switch between DCM and CCM for light-load efficiency in DCM. The switching frequency in CCM is internally set to 500kHz.

The device provides a maximum static regulation tolerance of ±1% over wide line, load and temperature ranges. The output is user adjustable, with external resistors, down to 0.8V. Pulling EN above 0.6V enables the controller. The regulator supports prebiased output.

Fault protection is provided by internal current limiting during positive or negative overcurrent conditions, output and input under and overvoltage detection and an over-temperature monitoring circuit.

Key Differences in Family
Part NumberInternal/External CompenstationExternal Frequency SyncProgrammable Soft-startSwitching FrequencyCurrent RatingDatasheet
ISL85003YesYesNo500kHz3Aisl85003-a.pdf
ISL85003AYesNoYes500kHz3Aisl85003-a.pdf
ISL85005YesYesNo500kHz5Aisl85005-05a.pdf
ISL85005AYesNoYes500kHz5Aisl85005-05a.pdf
Key Features
  • Input voltage range 4.5V to 18V
  • Output voltage adjustable from 0.8V, ±1%
  • Efficiency up to 95%
  • Integrated boot diode with undervoltage detection
  • Current mode control
    • DCM/CCM
    • Internal or external compensation options
    • 500kHz switching frequency option
    • External synchronization up to 2MHz on ISL85003
  • Adjustable soft-start time on the ISL85003A
  • Open-drain PG window comparator
    • Built-in protection
    • Positive and negative overcurrent protection
    • Overvoltage and thermal protection
    • Input overvoltage protection
  • Small 12 Ld 3mmx4mm Dual Flat No-Lead (DFN) package
Applications
  • Network and communication equipment
  • Industrial process control
  • Multifunction printers
  • Point-of-load regulators
  • Standard 12V rail supplies
  • Embedded computing
Typical Diagram
Application Notes
TitleTypeUpdatedSizeOther Languages
AN9208: High Frequency Power ConvertersPDF13 Nov 201478 KB
AN7244: Understanding Power MOSFETsPDF13 Nov 201441 KB
AN9209: A Spice-2 Subcircuit Representation for Power MOSFETs Using Empirical MethodsPDF13 Nov 201456 KB
AN9210: A New PSpice Subcircuit for the Power MOSFET Featuring Global Temperature OptionsPDF13 Nov 2014190 KB
Datasheets
TitleTypeUpdatedSizeOther Languages
ISL85003, ISL85003A DatasheetPDF17 Mar 20172.1 MB日本語
Design Files
TitleTypeUpdatedSizeOther Languages
ISL85003EVAL2Z Design FilesZIP13 Nov 2014818 KB
ISL85003DEMO1Z Design FilesZIP13 Nov 2014293 KB
User Guides
TitleTypeUpdatedSizeOther Languages
ISL85003-AEVAL2Z User GuidePDF20 Mar 2017620 KB
ISL85003-ADEMO1Z User GuidePDF20 Mar 2017396 KB
White Papers
TitleTypeUpdatedSizeOther Languages
How to Protect Buck Regulators from Overcurrent DamagePDF30 Mar 2017392 KB
Five Easy Steps to Create a Multi-Load Power SolutionPDF30 Jan 2017502 KB
Order Information
Part NumberPackage TypeWeight(g)PinsMSL RatingPeak Temp (°C)RoHS Status
ISL85003FRZ-T12 Ld DFN T+R0.022123260RoHS
ISL85003FRZ-TK12 Ld DFN T+R0.022123260RoHS
ISL85003FRZ-T7A12 Ld DFN T+R0.022123260RoHS
ISL85003FRZ12 Ld DFN0.022123260RoHS
ISL85003DEMO1ZN/ARoHS
ISL85003EVAL2ZN/ARoHS
ISL85003, ISL85003A Datasheet 17 Mar 2017
ISL85003, ISL85003A Datasheet 17 Mar 2017
12 Ld DFN T+R ISL85003A
AN9208: High Frequency Power Converters 13 Nov 2014
AN7244: Understanding Power MOSFETs 13 Nov 2014
AN9209: A Spice-2 Subcircuit Representation for Power MOSFETs Using Empirical Methods 13 Nov 2014
AN9210: A New PSpice Subcircuit for the Power MOSFET Featuring Global Temperature Options 13 Nov 2014
ISL85003EVAL2Z Design Files 13 Nov 2014
ISL85003DEMO1Z Design Files 13 Nov 2014
ISL85003-AEVAL2Z User Guide 20 Mar 2017
ISL85003-ADEMO1Z User Guide 20 Mar 2017
How to Protect Buck Regulators from Overcurrent Damage 30 Mar 2017
Five Easy Steps to Create a Multi-Load Power Solution 30 Jan 2017