I2C GPIO expanders feature configurable pull-up resistor and pin-compatible footprints

Nexperia has released a new portfolio of 16-channel I2C GPIO expanders created to improve flexibility and reuse in electronic systems. The portfolio offers an elegant solution for requiring extra I/Os while keeping the interconnections minimal, allowing design engineers to add new features with no increase in PCB design complexity and BOM. It incorporates the NCA9595, the industry’s first GPIO expander, to offer a register configurable internal pull-up resistor for customised power optimisation.

The number of sensor signals which need monitoring by a microcontroller continues to increase in line with the growth of the servers, automotive, industrial, medical and IoT, as does the number of LEDs employed as system status indicators. Microcontrollers are developed with limited numbers of GPIO ports, many are employed internally within a system, leaving just a small number of IOs available to connect to sensors or LEDs. With this limitation, I2C GPIO offers an extra 128 I/O channels.

The I2C GPIO portfolio also includes the NCA9535, NCA9539, NCA9555 and NCA9595 devices. These parts have been developed in pin-to-pin compatible packages with industry-standard footprints (TSSOP24 and HWQFN24) to provide a cost-effective and flexible solution for growing the number of parallel IOs in an electronic system. All the devices with features are mentioned below.

The NCA9595 differs from competing GPIO expanders by incorporating a register configurable internal pull-up resistor. This element removes the necessity for external pull-up resistors (saving board space and cost) and optimises power consumption based on customer needs.

Notably, all parts in the portfolio provide additional application features and benefits compared to similar competing devices – they have a lower standby current of 2.5uA (28% lower than the competition), output capacitance of 4.5pF (45% lower than the competition), and propagation delay of 280ns (6% faster than the competition), allowing lower power and faster GPIO to I2C (and reverse) response, respectively. All devices operate over a 1.65V-5.5V range and from -40C to +85C and -40C to +125C.