Highly Efficient 3A Synchronous Buck Regulator

Topology: Boost
Input Voltage (min.): 0.72 V
Input Voltage (max.): 0.85 V
Output 1: 1.80 V / 2.400 A

Original publication on 2018-01-25, revision 0.00


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.


  • 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
  • Small 12 Ld 3mmx4mm Dual Flat No-Lead (DFN) package


  Order Code SPEC Product series L
RDC typ.
RDC max.
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