Step-down DC/DC power switch regulator

ISL8540  description

The ISL8540 is a step-down DC/DC power switch regulator that accepts 9.0V to 40V inputs and provides 2A output current. The device has a 20 Ld HTSSOP package. The output voltage can be set between 1.21V and 35V via an external voltage divider.

The DMOS transistor devices using internal power, typical rDS (ON) 0.19Ω, in order to obtain high efficiency and high speed switch. Switching frequencies in the range of 100kHz ~ 600kHz can be achieved (the maximum power consumption of various packages must be observed).

Notable features of this next-generation DC/DC converter include pulse-to-pulse current limiting for FET protection, short circuit mode for short circuit protection, voltage feedforward regulation, frequency synchronization, soft start, typically low standby current of 60 μA in the disabled state, and thermal shutdown.

ISL8540 Pinout

 ISL8540 Block diagram

Typical schematic diagram of ISL8540 (5v vout)

Typical schematic diagram of ISL8540 (12v vout)

Features

• Voltage feedforward mode

• Step down DC/DC supporting up to 2A

• Input voltage range of 9.0V to 40V

• Internal reference of 1.21V ±1%

• Adjustable output voltage range of 1.21V to 35V

• Adjustable switching frequency 100kHz to 600kHz

• Frequency SYNC pin

• Zero load current operation

• Pulse-by-pulse mode current limit and Hiccup mode

• Low standby current of 60µA typical

• Thermal shutdown

• Load dump to 100V for 400ms

• Pb-free (RoHS compliant)

Applications

• Non-isolated telecom power supply

• Industrial and automotive power supplies

• Portable computers

• Battery chargers

• Distributed power systems