Highly Efficient 3A Synchronous Buck Regulator ISL85003, ISL85003A

Topology: Buck
Input Voltage (min.): 4.50 V
Input Voltage (max.): 18.00 V
Switching Frequency (min.): 400.00 kHz
Switching Frequency (max.): 600.00 kHz
Output 1: 5.00 V / 3.000 A

Original publication on 2014-03-21, revision 1


The ISL85003 and ISL85003A are synchronous buck regulators with integrated high-side and low-side FET’s. 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 3x4mm DFN package. The ISL85003 is designed on Intersil’s proprietary fab processthat is designed to deliver very low rDS(ON) FET’s 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 FET’s, the device delivers very high efficiencypower to the load. The ISL85003 can automatically switch between DCM andCCM 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 outputis user adjustable, with external resistors, down to 0.8V. PullingEN above 0.6V enables the controller. The regulator supportspre-biased 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.The regulator is available in a small 3x4mm Dual Flat No-Lead (DFN) package.


  • 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
  • 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


  Order Code SPEC Product series L
Material Version Samples
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