描述 Description

The PCA9554B and PCA9554C are low-voltage 8-bit General Purpose Input/Output(GPIO) expanders with interrupt for I2C-bus/SMBus applications. The only differencebetween the PCA9554B and PCA9554C is their I2C fixed address allowing a largernumber of the same device on the I2C-bus with no chance of address conflict. NXP I/Oexpanders provide a simple solution when additional I/Os are needed while keepinginterconnections 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 allowthe PCA9554B/PCA9554C to interface with next-generation microprocessors andmicrocontrollers where supply levels are dropping down to conserve power.
The PCA9554B/PCA9554C contain a register set of 8-bit Configuration, Input, Output,and Polarity Inversion registers.
The PCA9554B is a pin-to-pin replacement for the PCA9554, while the PCA9554Creplaces the PCA9554A. Both of these devices replace other industry-standard partnumbers. More fully-featured parts PCAL9554B and PCAL9554C are also available withAgile I/O features. See the respective data sheet for more details.
The PCA9554B/PCA9554C open-drain interrupt (INT) output is activated when any inputstate differs from its corresponding Input Port register state and is used to indicate to thesystem master 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, thePCA9554B/PCA9554C can remain 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.
All input/output pins have weak pull-up resistors connected to them to eliminate externalcomponents.
Three hardware pins (A0, A1, A2) select the fixed I2C-bus address and allow up to eightdevices to share the same I2C-bus/SMBus. The PCA9554B and PCA9554C differ only intheir base I2C-bus addresses permitting a total of 16 devices on the I2C-bus, minimizingthe chance for address conflict, even in the most complex system.

特性 Features

I2 C-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 inputs:Vhys = 0.10 x VDD (typical)
5 V tolerant I/Os
Open-drain active LOW interrupt output (INT)
400 kHz Fast-mode I2 C-bus
Input/output configuration register
Polarity inversion register
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