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PCAL9554B; PCAL9554C: Low-voltage 8-bit I²C-bus and SMBus low power I/O port with interrupt, weak pull-up and Agile I/O

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. The only 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 address conflicts. 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 PCAL9554B/PCAL9554C to interface with next-generation microprocessors and microcontrollers where supply levels are dropping down to conserve power.

The PCAL9554B/PCAL9554C contains the PCA9554A register set of four 8-bit Configuration, Input, Output, and Polarity Inversion registers, and additionally, the PCAL9554B/PCAL9554C 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 PCAL9554B is a pin-for-pin replacement for the PCA9554, while the PCAL9554C replaces 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 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 PCAL9554B or PCAL9554C can remain a simple slave device.

The device outputs have 25 mA sink capabilities for directly driving LEDs while consuming low device current.

Three hardware pins (A0, A1, A2) select the fixed I²C-bus address and allow up to eight devices to share the same I²C-bus/SMBus. The PCAL9554B and PCAL9554C differ only in their base I²C-bus addresses permitting a total of 16 of the same devices on the I²C-bus, minimizing the chance of address conflict, even in the most complex system.

Outline 3d SOT403-1

• Pin to pin replacement for PCA9554 and PCA9554B, PCA9554A and PCA9554C with interrupts disabled at power-up Software backward compatible with PCA9554 and PCA9554B, PCA9554A and PCA9554C
• 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 fall times in low capacitance applications Input latch: Input Port register values changes are kept until the Input Port register is 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 changes state

Data Sheets (1)

Application Notes (1)

Package Information (2)

Packing (1)

Supporting Information (1)

Design Support

• Expert mode sample code for 8-bit Totem Pole (REV 1.0) TXT 8-BIT-TOTEM-POLE-READ-WRITE 12/10/2014

Ordering Information

Package Information

Product ID	Package Description	Outline Version	Reflow/Wave Soldering	Packing	Product Status	Part NumberOrdering code(12NC)	Marking	Chemical Content	RoHS / Pb Free / RHF	LeadFree Conversion Date	MSL	MSL LF
PCAL9554BBS		SOT758-1		Reel 13" Q2/T3	Active	PCAL9554BBSHP (9352 993 93128)	L4B	PCAL9554BBS		Always Pb-free	1	1
PCAL9554BPW		SOT403-1	SSOP-TSSOP-VSO-WAVE	Reel 13" Q1/T1	Active	PCAL9554BPWJ (9352 993 92118)	PL9554B	PCAL9554BPW		Always Pb-free	1	1
PCAL9554CPW		SOT403-1	SSOP-TSSOP-VSO-WAVE	Reel 13" Q1/T1	Active	PCAL9554CPWJ (9352 993 94118)	PL9554C	PCAL9554CPW		Always Pb-free	1	1
PCAL9554CBS		SOT758-1		Reel 13" Q2/T3	Active	PCAL9554CBSHP (9352 993 95128)	L4C	PCAL9554CBS		Always Pb-free	1	1