TI PCA9538PWR

The PCA9538 is an 8-bit I/O expander compliant with the two-wire bidirectional I2C bus (or SMBus) protocol, designed for general-purpose parallel input/output (I/O) expansion. The device operates over a supply voltage range of 2.3V to 5.5V and supports clock frequencies of 100kHz (standard mode) and 400kHz (fast mode). When additional I/O is needed for switches, sensors, buttons, LEDs, fans, and similar peripherals, this device and other I/O expanders provide a simple solution.

The PCA9538 features an interrupt generation on the INT pin whenever an input port state changes. Hardware-selectable address pins A0 and A1 allow up to four PCA9538 devices to reside on the same I2C bus. The device can also be reset to its default state via the reset function or by power cycling to generate a power-on reset.

INT can be connected to the interrupt input of a microcontroller. By asserting an interrupt signal on this line, the remote I/O can notify the microcontroller whether input data is present on its ports, without requiring communication over the I2C bus. Therefore, the PCA9538 can also function as a simple slave device.

The device's latched outputs feature high-current drive capability for direct LED driving, with low current consumption.

Two hardware pins (A0 and A1) are used to program and alter the fixed I2C address, allowing up to four devices to share the same I2C bus or SMBus.

• 1μA low standby current consumption (maximum)
• I2C to parallel port expander
• Open-drain active-low interrupt output
• Active-low reset input
• Operating supply voltage range: 2.3V to 5.5V
• 5V-tolerant I/O ports
• 400kHz fast-mode I2C bus
• Two hardware address pins allow up to four devices on I2C/SMBus
• Input and output configuration registers
• Polarity inversion register
• All channels configured as inputs at power-up
• Glitch-free at power-up
• Noise filter on SCL/SDA inputs
• Latched outputs with maximum high-current drive capability for direct LED driving
• Latch-up performance exceeds 100mA per JESD78 Class II
• ESD protection performance exceeds JESD22 requirements
• 2000V Human Body Model (A114-A)
• 200V Machine Model (A115-A)
• 1000V Charged Device Model (C101)