The NCA9555B is a 24-pin device that provides 16 bits of General Purpose parallel Input/Output (GPIO) expansion for the two-line bidirectional I2C bus applications. It provides a simple solution when additional I/Os are needed for ACPI power switches, sensors, push buttons, LEDs, fans, etc. The NCA9555B consists of two 8-bit Configuration (Input or Output selection); Input, Output and Polarity Inversion (active HIGH or active LOW operation) registers. The system master can enable the I/Os as either inputs or outputs by writing to the I/O configuration bits. The data for each Input or Output is kept in the corresponding Input or Output register. The polarity of the read register can be inverted with the Polarity Inversion register. All registers can be read by the system master. The NCA9555B open-drain interrupt output is activated when any input state differs from its corresponding input port register state and is used to indicate to the system master that an input state has changed. The power-on reset sets the registers to their default values and initializes the device state machine. Three hardware pins (A0, A1, A2) vary the fixed I2C-bus address and allow up to eight devices to share the same I2C-bus.
Product Features
? I2C to Parallel Port Expander
? Operating power supply voltage range of 1.65 V to 5.5 V
? Low standby current
? Open-drain active-low interrupt output
? 5.5 V tolerant, 16 I/O ports which default to input mode
? Compatible with most microcontrollers
? Up to 400 kHz clock frequency
? Noise filter on SCL/SDA inputs
? Polarity Inversion register
? Internal power-on reset
? No glitch on power-up
? Address by three hardware address pins for use of up to eight devices
? Latched outputs with high-current drive capability for directly driving LEDs
? Latch-up performance exceeds 100 mA per JESD 78, class IIESD protection exceeds JESD 22: 2000 V HBM, 200 V MM, and 1000 V CDM
Application
? GPIO expansion for I2C-bus applications
? Servers, personal computers, personal electronics
? Routers (Telecom Switching Equipment)
? Products with GPIO-Limited processors
Functional Block Diagram
For more product information, please contact us.
