TCA9539PWR

TCA9539PWR is a Texas Instruments 16-bit I2C/SMBus I/O expander in a 24-pin TSSOP package, tape and reel — for adding sixteen GPIOs over two wires in keypads, LED banks and industrial I/O where the host MCU has run out of pins. Beyond raw pin count, it carries an interrupt output, a hardware reset pin and configuration registers, so slow inputs can be serviced on change instead of polled. It operates from 1.65 V to 5.5 V at up to 400 kHz, sitting directly on low-voltage logic rails without level shifting. The code recently registered one of the largest daily gains on ic.net.cn's price-movement board, evidence of active market demand. Selection advice: the PWR suffix denotes TSSOP-24 on tape and reel — match the full code to your layout. Do not confuse this expander with the TCA9548A switch also listed here: the switch multiplexes one bus to several downstream buses to resolve address clashes, while the TCA9539 creates new GPIO — designs short of pins need this part, designs short of addresses need the other. TI lists this part as ACTIVE. Parameters verified against the TI official product page.