SX1509QBIULTRT

Overview

The SX1509QBIULTRT is a 16-channel General Purpose Input/Output (GPIO) expander manufactured by Semtech Corporation. It operates on an I2C serial interface with a maximum clock frequency of 400 kHz and supports supply voltages ranging from 1.2 V to 3.6 V. The device features open-drain and push-pull outputs capable of sourcing or sinking up to 8 mA and 15 mA respectively. It includes integrated LED drivers, a keypad engine, and power-on reset functionality. The component is housed in a 28-lead Ultra Thin Quad Flat No-Lead (QFN-UT) package measuring 4x4 mm, designed for surface-mount installation.

Feature Summary

• Ultra-low voltage operation suitable for battery-powered handheld devices
• Integrated LED driver and keypad engine for direct peripheral control
• Global level shifting capability between different voltage domains

Applications

• Low-power handheld battery-operated equipment
• Systems requiring serial expansion of microcontroller I/O ports
• Remote communication and control interfaces

Procurement Notes

Verify the specific suffix 'QB' against official Semtech documentation to confirm pinout and functional compatibility, as suffixes often denote package variations or temperature grades. Ensure the ordering part number matches the exact datasheet revision required for your design. Cross-reference the 28-QFN-UT package dimensions with your PCB footprint library to prevent assembly errors during production.

Selection Notes

Select this component when the system requires expanding GPIO capacity via I2C while supporting low-voltage logic levels down to 1.2 V. It is appropriate for designs needing integrated LED driving and keypad scanning without additional discrete components. Consider the 28-pin QFN package constraints and thermal dissipation requirements for high-density board layouts.

Part Context

This part belongs to the SX1509B family of ultra-low voltage GPIO expanders. It shares architectural similarities with the SX1508B and SX1507B models but provides 16 channels compared to their 8 or 4 channel configurations. The 'QB' suffix typically indicates a specific package variant within the PerSe product line, distinct from standard commercial grade parts.

Replacement Considerations

The SX1509BIULTRT is a related model within the same family. Verify if the 'I' versus 'Q' suffix denotes a difference in operating temperature range or package material before substituting. Ensure any replacement maintains the 28-QFN-UT form factor and I2C interface compatibility.