描述 Description

The PCAL9554B and PCAL9554C are a low-voltage 8-bit General Purpose Input/Output(GPIO) expanders with interrupt and weak pull-up for I2C-bus/SMBus applications. Theonly difference between the PCAL9554B and PCAL9554C is their I2C-bus fixed address,allowing a larger number of the same device on the I2C-bus with no chance of addressconflicts. NXP? I/O expanders provide a simple solution when additional I/Os are neededwhile 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 Vallows the PCAL9554B/PCAL9554C to interface with next-generation microprocessorsand microcontrollers where supply levels are dropping down to conserve power.
The PCAL9554B/PCAL9554C contains the PCA9554A register set of four 8-bitConfiguration, Input, Output, and Polarity Inversion registers, and additionally, thePCAL9554B/PCAL9554C has Agile I/O, which are additional features specificallydesigned to enhance the I/O. These additional features are programmable output drivestrength, latchable inputs, programmable pull-up/pull-down resistors, maskable interrupt,interrupt status register, programmable open-drain or push-pull outputs.
The PCAL9554B is a pin-for-pin replacement for the PCA9554, while the PCAL9554Creplaces the PCA9554A, however both versions power-up with all I/O interrupted masked.This mask default allows for a board bring-up free of spurious interrupts at power-up.
The PCAL9554B/PCAL9554C open-drain interrupt (INT) output is activated when anyinput state differs from its corresponding Input Port register state and is used to indicate tothe system 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, the PCAL9554B orPCAL9554C can remain a simple slave device.
The device outputs have 25 mA sink capabilities for directly driving LEDs while consuminglow device current.
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 PCAL9554B and PCAL9554C differ onlyin their base I2C-bus addresses permitting a total of 16 of the same devices on theI2C-bus, minimizing the chance of address conflict, even in the most complex system.

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 inputs
? Vhys = 0.10 x VDD (typical)
? 5 V tolerant I/Os
? 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
Agile I/O features
? Pin to pin replacement for PCA9554 and PCA9554B, PCA9554A and PCA9554C withinterrupts disabled at power-up
? Software backward compatible with PCA9554 and PCA9554B, PCA9554A andPCA9554C
? Output port configuration: bank selectable push-pull or open-drain output stages
? Interrupt status: read-only register identifies the source of an interrupt
? Bit-wise I/O programming features:
? Output drive strength: four programmable drive strengths to reduce rise and falltimes in low capacitance applications
? Input latch: Input Port register values changes are kept until the Input Port registeris read
? Pull-up/pull-down enable: floating input or pull-up/down resistor enable
? Pull-up/pull-down selection: 100 kΩ pull-up/down resistor selection
? Interrupt mask: mask prevents the generation of the interrupt when input changesstate