Date: 26/11/2006

New PWM controllers from Intersil saves current sensing resistor.

The new PWM controllers ISL6545 and ISL6545A from Intersil integrate few key on board components into the chip itself. The boot diode, current sensing function and MOSFET drivers are packed in the chip. The current sensing is done by measuring the lower MOSFET's on-resistance, rDS(ON). Both have fixed frequency oscillator (300kHz for ISL6545; 600KHz for ISL6545A) to save some space and circuit complexity.

Work on single feedback loop and voltage-mode control and drive N-channel MOSFETs in a synchronous buck topology. Can work from input voltage range of 1.0V to 12V. The lowest output voltage is 0.6V and with a tolerance of +/-1%. The error amplifiers inside the chips provide 20MHz gain bandwidth product and 9V/microsecond slew-rate. There is also a soft start feature.

The applications suggested are, PCs, DSPs, Embedded controllers, PC add-on cards, cable/DSL modems, set top boxes.
RoHS: available

Package: ISL6545: 8 lead SOIC.
ISL6545A: 10 lead QFN package
Price: ISL6545: $1.00 each in 1K quantities
ISL6545A: $1.51 each in 1K quantities