Intersil - Three-Channel Wide Vin Step-Down Controllers Provide Efficient, Compact Power Solutions

ISL9443/4 Provide Design Flexibility for Multi-Output Power Supplies

The ISL9443 and ISL9444 incorporate three independent synchronous buck (step-down) controllers with flexible enable, tracking and sequencing features. The controllers’ 180 degree out-of-phase operation and internal compensation minimize ripple and reduce the need for external components. With an integrated 5V bias LDO, they can operate over a wide Vin range of 4.5V to 26V. The output voltage can be programmed from 0.7V to as high as 90% of Vin.

Diode emulation mode with pulse-skipping optimizes light-load efficiency and reduces standby current to only 30uA. For high power applications, the controllers include low resistance gate drivers to support up to 25 amps per channel. Programmable switching frequency of 200kHz to 1.2MHz (or external synchronization) and multiple protection capabilities provide designers with robust performance and optimal flexibility to tradeoff size versus efficiency.

The includes a number of additional features to enhance system functionality. It features a power failure monitor, three independent enables, and three independent Power Good signals, each with adjustable delay. An optional 5V bias input bypasses the internal LDO to reduce power dissipation within the package.

Features and Specifications
Wide input voltage range of 4.5V to 26V
32uA (typical) standby current delivers excellent light-load efficiency with low output voltage ripple Precision 1% voltage reference tolerance Adjustable switching frequency of 200kHz to 1.2MHz permits user tradeoff between efficiency and size Internal compensation supports all-ceramic output capacitors Adaptive shoot-through protection with over-current, over-voltage and over-temperature protection