PCA9538A: Low-voltage 8-bit I²C-bus I/O port with interrupt and reset

The PCA9538A 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 PCA9538A to interface with next-generation microprocessors and microcontrollers 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-standard devices. A more fully functional device, the PCAL9538A, is available with Agile I/O features. See the respective data sheet for more details.

The PCA9538A 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 PCA9538A can remain a simple slave device.

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

The power-on reset sets the registers to their default values and initializes the device state machine. In the PCA9538A, the RESET pin causes the same reset/default I/O input configuration to occur without de-powering the device, holding the registers and I²C-bus state machine in their default state until the RESET input is once again HIGH. This input requires a pull-up to VDD.

Two hardware pins (A0, A1) select the fixed I²C-bus address and allow up to four devices to share the same I²C-bus/SMBus.

Outline 3d SOT403-1

Data Sheets (1)

Name/Description	Modified Date
Low-voltage 8-bit I2C-bus I/O port with interrupt and reset (REV 1.0) PDF (2.4 MB) PCA9538A	28 Sep 2012

Application Notes (1)

Name/Description	Modified Date
Low Voltage Agile I/O GPIO Input/Output Characteristics (REV 1.0) PDF (443.0 kB) AN11496	15 Aug 2014

Package Information (2)

Name/Description	Modified Date
plastic thin shrink small outline package; 16 leads; body width 4.4 mm (REV 1.0) PDF (300.0 kB) SOT403-1	08 Feb 2016
plastic thermal enhanced very thin quad flat package; no leads; 16 terminals; body 3 x 3 x 0.85 mm (REV 1.0) PDF (201.0 kB) SOT758-1	08 Feb 2016

Packing (1)

Name/Description	Modified Date
TSSOP16; Reel pack; SMD, 13" Q1/T1 Standard product orientation Orderable part number ending ,118 or... (REV 1.0) PDF (218.0 kB) SOT403-1_118	08 Apr 2013

Supporting Information (1)

Name/Description	Modified Date
Footprint for wave soldering (REV 1.0) PDF (16.0 kB) SSOP-TSSOP-VSO-WAVE	08 Oct 2009

Ordering Information

Product	Status
PCA9538ABS	Active
PCA9538APW	Active

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
PCA9538APW		SOT403-1	SSOP-TSSOP-VSO-WAVE	Reel 13" Q1/T1	Active	PCA9538APWJ (9352 993 87118)	PA9538A	PCA9538APW		Always Pb-free	1	1
PCA9538ABS		SOT758-1		Reel 13" Q2/T3	Active	PCA9538ABSHP (9352 993 88128)	P3A	PCA9538ABS		Always Pb-free	1	1