DATASHEET
ISL85403 FN8631
Rev 1.00
March 13, 2015 2.5A Regulator with Integrated High-side MOSFET for Synchronous Buck or
Boost Buck Converter
The ISL85403 is a 40V, 2.5A synchronous buck or boost buck
controller with a high-side MOSFET and low-side driver
integrated. In buck mode, the ISL85403 supports a wide input
range of 3V to 40V. In boost-buck mode, the input range can
be extended down to 2.5V and output regulation can be
maintained when VIN drops below VOUT, enabling sensitive
electronics to remain on in low input voltage conditions.
The ISL85403 has a flexible selection of operation modes of
forced PWM mode and PFM mode. In PFM mode, the
quiescent input current is as low as 180ВµA (AUXVCC connected
to VOUT). The load boundary between PFM and PWM can be
programmed to cover wide applications.
The low-side driver can be either used to drive an external low-side
MOSFET for a synchronous buck or left unused for a standard
non-synchronous buck. The low-side driver can also be used to
drive a boost converter as a preregulator followed by a buck
controlled by the same IC, which greatly expands the operating
input voltage range down to 2.5V or lower (Refer to “Typical …
