Overview
The PCA9539RPW,112, produced by NXP USA Inc., is a 24-pin CMOS device designed to provide 16 bits of general-purpose parallel Input/Output (GPIO) expansion. This device is part of the I2C-bus and SMBus family of I/O expanders, enhancing the capabilities of microcontrollers by adding additional I/O ports. It is particularly useful in applications requiring more I/Os for devices such as ACPI power switches, sensors, push buttons, LEDs, and fans.
Key Specifications
| Parameter | Description |
|---|---|
| Number of I/Os | 16 bits |
| Interface | I2C-bus, SMBus |
| Operating Voltage | 2.3 V to 5.5 V (3.0 V to 5.5 V for PCA9539PW/Q900 and PCA9539RPW/Q900) |
| Package Type | 24-TSSOP (0.173, 4.40mm Width) |
| Interrupt Output | Open-drain active-low interrupt output |
| Reset Input | Active-low reset input |
| I/O Configuration | Configurable as inputs or outputs via I/O configuration bits |
| Polarity Inversion | Active-high or active-low operation via Polarity Inversion register |
| Power Consumption | Low standby-current consumption of 1 μA max |
| Addressing | Two hardware pins (A0, A1) for varying the fixed I2C-bus address, allowing up to four devices to share the same I2C bus or SMBus |
Key Features
- 16-bit I2C-bus GPIO with interrupt and reset capabilities
- Operating power supply voltage range of 2.3 V to 5.5 V
- 5 V tolerant I/Os
- Low standby-current consumption of 1 μA max
- Configurable I/O ports as inputs or outputs via I/O configuration bits
- Polarity inversion for active-high or active-low operation
- Open-drain active-low interrupt output to indicate input state changes
- High-current drive capability for directly driving LEDs
- Power-on reset and active-low reset input for initializing the device
Applications
The PCA9539RPW,112 is suitable for a variety of applications where additional I/O ports are required. These include:
- ACPI power switches
- Sensors and monitoring systems
- Push buttons and user interfaces
- LED indicators and display systems
- Fan control and other peripheral devices
Q & A
- What is the PCA9539RPW,112 used for?
The PCA9539RPW,112 is used to provide 16 bits of general-purpose parallel Input/Output (GPIO) expansion for microcontrollers via the I2C-bus or SMBus interface.
- What is the operating voltage range of the PCA9539RPW,112?
The operating voltage range is from 2.3 V to 5.5 V, with specific models operating from 3.0 V to 5.5 V.
- How are the I/O ports configured?
The I/O ports can be configured as either inputs or outputs by writing to the I/O configuration bits.
- What is the purpose of the interrupt output?
The open-drain active-low interrupt output is activated when any input state differs from its corresponding input port register state, indicating to the system master that an input state has changed.
- How does the reset function work?
The PCA9539RPW,112 has an active-low reset input. In the PCA9539, the reset sets the registers to their default values and initializes the I2C/SMBus state machine. In the PCA9539R, the reset only initializes the device state machine without changing the internal general-purpose registers.
- Can multiple PCA9539RPW,112 devices share the same I2C bus?
Yes, up to four devices can share the same I2C bus or SMBus by using two hardware pins (A0 and A1) to vary the fixed I2C-bus address.
- What is the power consumption of the PCA9539RPW,112 in standby mode?
The device has a low standby-current consumption of 1 μA max.
- Are the I/Os 5 V tolerant?
Yes, the I/Os of the PCA9539RPW,112 are 5 V tolerant.
- Can the PCA9539RPW,112 drive LEDs directly?
Yes, the device outputs have high-current drive capability for directly driving LEDs.
- What happens to the I/O ports during a power-on reset?
During a power-on reset, all registers return to their default values, and the I/O ports are configured as inputs.
