The PCA9539PW from Texas Instruments is a highly sophisticated and efficient low-voltage 16-bit I2C and SMBus I/O expander.

• Function: General-purpose remote I/O expansion
• Interface: Two-wire serial interface
• Supply Voltage Range: 2.3 to 5.5 V
• Standby Current: Low
• I/O Pins: 16 I/O pins that can be used as inputs, outputs, or both
• Current Sink: Up to 25 mA
• LED Drive: Can drive LEDs directly
• Level Shifting: Built-in level shifting feature
• Interrupt Output: Configurable to alert the microcontroller when there is a change in the input state
• Package: TSSOP24 package
• Hot Insertion: Supported