PCA6408ABSHP

The PCA6408A is an 8-bit general purpose I/O expander that provides remote I/O expansion for most microcontroller families via the I²C-bus interface. NXP I/O expanders provide a simple solution when additional I/Os are needed while keeping interconnections to a minimum, for example, in battery-powered mobile applications for interfacing to sensors, push buttons, keypad, etc. In addition to providing a flexible set of GPIOs, it simplifies interconnection of a processor running at one voltage level to I/O devices operating at a different (usually higher) voltage level. The PCA6408A has built-in level shifting feature that makes these devices extremely flexible in mixed signal environments where communication between incompatible I/O voltages is required. Its wide VDD range of 1.65 V to 5.5 V on the dual power rail allows seamless communications with next-generation low voltage microprocessors and microcontrollers on the interface side (SDA/SCL) and peripherals at a higher voltage on the port side. There are two supply voltages for PCA6408A: VDD(I2C-bus) and VDD(P). VDD(I2C-bus) provides the supply voltage for the interface at the master side (for example, a microcontroller) and the VDD(P) provides the supply for core circuits and Port P. The bidirectional voltage level translation in the PCA6408A is provided through VDD(I2C-bus). VDD(I2C-bus) should be connected to the VDD of the external SCL/SDA lines. This indicates the VDD level of the I²C-bus to the PCA6408A. The voltage level on Port P of the PCA6408A is determined by the VDD(P). The PCA6408A consists of one 8-bit Configuration (input or output selection), Input, Output, and Polarity Inversion (active HIGH) register. At power-on, the I/Os are configured as inputs.

• I²C-bus to parallel port expander
• Operating power supply voltage range of 1.65 V to 5.5 V
• Allows bidirectional voltage-level translation and GPIO expansion between:
  • 1.8 V SCL/SDA and 1.8 V, 2.5 V, 3.3 V or 5 V Port P
  • 2.5 V SCL/SDA and 1.8 V, 2.5 V, 3.3 V or 5 V Port P
  • 3.3 V SCL/SDA and 1.8 V, 2.5 V, 3.3 V or 5 V Port P
  • 5 V SCL/SDA and 1.8 V, 2.5 V, 3.3 V or 5 V Port P
• Low standby current consumption of 1 µA
• Schmitt-trigger action allows slow input transition and better switching noise immunityat the SCL and SDA inputs:
  • V_hys = 0.18 V (typical) at 1.8 V
  • V_hys = 0.25 V (typical) at 2.5 V
  • V_hys = 0.33 V (typical) at 3.3 V
  • V_hys = 0.5 V (typical) at 5 V
• 5 V tolerant I/O ports
• Active LOW reset input (RESET)
• Open-drain active LOW interrupt output (INT)
• 400 kHz Fast-mode I²C-bus
• Input/Output Co