PCAL9539AHF,128

I/o Expanders Overview

The PCAL9539AHF,128 is a low-voltage 16-bit General Purpose Input/Output (GPIO) expander designed for I2C-bus and SMBus applications. It features an operating power supply voltage range of 1.65 V to 5.5 V and supports Fast-mode communication at 400 kHz. The device includes an active LOW reset input and an open-drain active LOW interrupt output. It offers Agile I/O capabilities such as programmable output drive strength, latchable inputs, and programmable pull-up/pull-down resistors. Packaged in a 24-terminal HWQFN with dimensions of 4 x 4 x 0.75 mm, it operates within a temperature range of -40 °C to +85 °C.

I/o Expanders Feature Summary

• Agile I/O configuration including programmable output drive strength, latchable inputs, and selectable pull-up/pull-down resistors
• Interrupt masking and status registers allow selective monitoring of input state changes without spurious signals during power-up
• Active LOW hardware reset pin enables system initialization without requiring power cycling
• Pin-to-pin compatibility with PCA9539 and PCA9539A families while providing enhanced software backward compatibility

I/o Expanders Applications

• ACPI power switches
• Sensor interface expansion
• Push button matrix scanning
• LED control circuits
• Fan speed control systems

I/o Expanders Procurement Notes

Verify the ordering suffix ,128 corresponds to the HWQFN24 package and reel packing method. Confirm that the component meets RoHS3 compliance standards and check the specific moisture sensitivity level requirements for your assembly process. Ensure the supplier provides valid traceability documentation for the NXP Semiconductors manufacturing origin.

I/o Expanders Selection Notes

Select this component when interfacing with microprocessors requiring additional GPIOs while minimizing interconnections. The wide voltage range supports next-generation low-power designs. Consider the Agile I/O features if application requirements include programmable drive strengths or input latching. Verify that the 24-HWQFN package fits the available PCB footprint and thermal management constraints.

I/o Expanders Part Context

The PCAL9539AHF,128 belongs to the PCAL9539A series of low-voltage I/O expanders. It serves as a direct pin-to-pin replacement for the PCA9539 and PCA9539A devices. Unlike its predecessors, it powers up with all I/O interrupts masked to prevent spurious signals during board bring-up. This evolution enhances reliability in systems requiring stable initialization sequences.

I/o Expanders Replacement Considerations

PCAL9539APW is a compatible alternative in the TSSOP24 package. Both variants share identical electrical characteristics and register sets. Select based on packaging preference and thermal dissipation requirements rather than functional differences.