描述 Description

The PCA9538A is a low-voltage 8-bit General Purpose Input/Output (GPIO) expanderwith interrupt and reset for I2C-bus/SMBus applications. NXP I/O expanders provide asimple solution when additional I/Os are needed while keeping interconnections to aminimum, 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 Vallows the PCA9538A to interface with next-generation microprocessors andmicrocontrollers where supply levels are dropping down to conserve power.
The PCA9538A contains the PCA9538A register set of four 8-bit Configuration, Input,Output, and Polarity Inversion registers.
The PCA9538A is a pin-to-pin replacement for the PCA9538 and other industry-standarddevices. A more fully functional device, the PCAL9538A, is available with Agile I/Ofeatures. See the respective data sheet for more details.
The PCA9538A open-drain interrupt (INT) output is activated when any input state differsfrom its corresponding Input Port register state and is used to indicate to the systemmaster that an input state has changed.
INT can be connected to the interrupt input of a microcontroller. By sending an interruptsignal on this line, the remote I/O can inform the microcontroller if there is incoming dataon its ports without having to communicate via the I2C-bus. Thus, the PCA9538A canremain a simple slave device.
The device outputs have 25 mA sink capabilities for directly driving LEDs while consuminglow device current.
The power-on reset sets the registers to their default values and initializes the device statemachine. In the PCA9538A, the RESET pin causes the same reset/default I/O inputconfiguration to occur without de-powering the device, holding the registers and I2C-busstate machine in their default state until the RESET input is once again HIGH. This inputrequires a pull-up to VDD.
Two hardware pins (A0, A1) select the fixed I2C-bus address and allow up to four devicesto share the same I2C-bus/SMBus.

特性 Features

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 VDD)
1.0 μA (typical at 3.3 V VDD)
Schmitt-trigger action allows slow input transition and better switching noise immunityat the SCL and SDA inputsVhys = 0.10 x VDD (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)
Packages offered: TSSOP16 and HVQFN16