PCAL9538APWJ

The PCAL9538A is a low-voltage 8-bit General Purpose Input/Output (GPIO) expander with interrupt and reset for I²C-bus/SMBus applications. NXP I/O expanders provide a simple solution when additional I/Os are needed while keeping interconnections to a minimum, for example, in ACPI power switches, sensors, push buttons, LEDs, fan control, etc. In addition to providing a flexible set of GPIOs, the wide VDD range of 1.65 V to 5.5 V allows the PCAL9538A to interface with next-generation microprocessors and microcontrollers where supply levels are dropping down to conserve power. The PCAL9538A contains the PCA9538A register set of four 8-bit Configuration, Input, Output, and Polarity Inversion registers, and additionally, the PCAL9538A has Agile I/O, which are additional features specifically designed to enhance the I/O. These additional features are: programmable output drive strength, latchable inputs, programmable pull-up/pull-down resistors, maskable interrupt, interrupt status register, programmable open-drain or push-pull outputs. The PCAL9538A is a pin-to-pin replacement for the PCA9538, however, the PCAL9538A powers up with all I/O interrupts masked. This mask default allows for a board bring-up free of spurious interrupts at power-up. The PCAL9538A open-drain interrupt (INT\) 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. INT\ can be connected to the interrupt input of a microcontroller. By sending an interrupt signal on this line, the remote I/O can inform the microcontroller if there is incoming data on its ports without having to communicate via the I²C-bus. Thus, the PCAL9538A can remain a simple slave device.

• I²C-bus to parallel port expander
• Operating power supply voltage range of 1.65 V to 5.5 V
• Low standby current consumption:
  • 1.5 µA (typical at 5 V V_DD)
  • 1.0 µA (typical at 3.3 V V_DD)
• Schmitt-trigger action allows slow input transition and better switching noise immunityat the SCL and SDA inputs
  • V_hys = 0.10 x V_DD (typical)
• 5 V tolerant I/Os
• Active LOW reset input (RESET)
• Open-drain active LOW interrupt output (INT)
• 400 kHz Fast-mode I²C-bus
• Internal power-on reset
• Power-up with all channels configured as inputs
• No glitch on power-up
• Latched outputs with 25 mA drive maximum capability for directly driving LEDs
• Latch-up performance exceeds 100 mA per JESD78, Class II
• ESD protection exceeds JESD22:
  • 2000 V Human Body Model (A114-A)
  • 1000 V Charged-Device Model (C101)