GPIO expansion for mixed-voltage I2C buses
The TCA9536DGKR is a 4-bit I²C and SMBus GPIO expander from Texas Instruments, providing general-purpose remote I/O expansion for microcontrollers through a two-wire serial interface. It operates from a 1.65 V to 5.5 V supply, allowing direct connection to both low-voltage core logic and legacy 5 V peripherals without a level translator. With a 1 MHz clock rate and an open-drain interrupt output, the part signals the host on input changes without polling, reducing bus traffic in latency-sensitive applications.
I/O count, drive, and temperature range
Four configurable I/O pins each sink 25 mA or source 10 mA, sufficient to drive LEDs or small relays directly through the open-drain outputs. The POR (power-on reset) feature ensures the outputs default to a known high-impedance state at power-up, preventing unintended actuator activation during supply ramp. Rated for -40°C to +125°C operation, the device suits industrial enclosures, engine-bay electronics, and outdoor telecom gear where ambient temperatures exceed the commercial 85°C ceiling.
Package and footprint options
Available in an 8-pin VSSOP (DGK) package — also listed as 8-TSSOP or 8-MSOP with a 3.00 mm body width — the footprint is shared across multiple TI GPIO expanders, simplifying PCB layout reuse. Supplied in Tape & Reel or Cut Tape for both prototyping and production volumes.
Lifecycle and sourcing posture
The part is sourced through authorized and independent distribution channels; current pricing and lead time are confirmed at RFQ against the BOM quantity.