ISL9440IRZ

Overview

The ISL9440IRZ is a quad-output synchronous buck controller integrating three PWM controllers and one low-dropout linear regulator controller. Designed for multi-rail power in cable/satellite set-top boxes, VoIP gateways, and cable modems, it features 300 kHz switching frequency with 180° phase shifting to reduce input ripple. Outputs are adjustable down to 0.8V. It includes internal soft-start, independent enable inputs for sequencing, and integrated UV/OV/OC/OT protections within a 5mm x 5mm QFN package.

Feature Summary

• Integrates three synchronous buck PWM controllers and one LDO controller for compact multi-rail power solutions.
• Features 180-degree phase-shifted PWM operation to minimize RMS input current and voltage ripple.
• Provides independent enable inputs to facilitate precise supply rail sequencing.

Applications

• Cable and satellite set-top boxes
• VoIP gateways
• Cable modems

Procurement Notes

Verify the specific suffix 'IRZ' against the manufacturer's official datasheet to confirm pinout compatibility and thermal pad requirements. Confirm that the 300 kHz switching frequency aligns with system design constraints. Ensure the 5mm x 5mm QFN package footprint matches the PCB layout specifications before finalizing procurement.

Selection Notes

Select this component when designing systems requiring four distinct output rails from a single controller IC. The integrated LDO complements the three buck converters for low-noise applications. Verify that the 0.8V minimum output voltage meets the lowest load requirement. Consider the internal loop compensation benefits for reducing external component count and total solution cost.

Part Context

The ISL9440 series belongs to Renesas' portfolio of mixed-signal power management ICs designed for home connectivity and industrial applications. It utilizes current mode control with feed-forward to maintain stability across various operating conditions without requiring complex external compensation networks.

Replacement Considerations

ISL9440A (600 kHz) and ISL9441 (no early warning) are functionally similar variants within the same family. Verify if the different switching frequencies or feature sets meet the specific application requirements before substitution.