Overview
The PCA9538APWJ, produced by NXP USA Inc., is an 8-bit I2C and SMBus low-power I/O expander. This device is designed to provide general-purpose parallel input and output expansion for the two-line bidirectional I2C bus or SMBus protocol. It operates within a power supply range of 2.3 V to 5.5 V, making it versatile for various applications. The PCA9538APWJ is particularly useful when additional I/Os are needed for components such as switches, sensors, push-buttons, LEDs, and fans.
Key Specifications
| Parameter | Value | Notes |
|---|---|---|
| Operating Power-Supply Voltage | 2.3 V to 5.5 V | |
| Standby Current Consumption | 1 μA max | |
| I2C Bus Frequency | 100 kHz (Standard-mode), 400 kHz (Fast-mode) | |
| Hardware Address Pins | A0 and A1 | Allow up to four devices on the same I2C bus |
| Interrupt Output | Open-drain active-low | Generated on INT pin when input port changes state |
| Reset Input | Active-low | Can be reset by cycling the power supply or using the RESET feature |
| ESD Protection | 2000-V Human-body model, 200-V Machine model, 1000-V Charged-device model | JESD 22 and JESD 78 compliant |
| Output Current Capability | Up to 25 mA per I/O, 200 mA total for P port | |
| Package Options | SSOP (16), TVSOP (16), SOIC (16), TSSOP (16) | Varying body sizes |
Key Features
- Low standby current consumption of 1 μA max
- I2C to parallel port expander
- Open-drain active-low interrupt output
- Active-low reset input
- 5-V tolerant I/O ports
- 400-kHz Fast I2C bus capability
- Input and output configuration register
- Polarity inversion register
- Power-up with all channels configured as inputs
- No glitch on power-up
- Noise filter on SCL/SDA inputs
- Latched outputs with high-current drive capability for directly driving LEDs
- ESD protection exceeding JESD 22 and JESD 78 standards
Applications
The PCA9538APWJ is suitable for a variety of applications where additional I/O expansion is required. These include:
- Switches and push-buttons
- Sensors and monitoring systems
- LED indicators and displays
- Fans and other small motors
- General-purpose I/O expansion in microcontroller-based systems
Q & A
- What is the operating voltage range of the PCA9538APWJ?
The PCA9538APWJ operates within a power supply range of 2.3 V to 5.5 V.
- What are the I2C bus frequencies supported by the PCA9538APWJ?
The device supports both 100 kHz (Standard-mode) and 400 kHz (Fast-mode) I2C bus frequencies.
- How many devices can be connected on the same I2C bus using the PCA9538APWJ?
Up to four devices can be connected on the same I2C bus using the A0 and A1 hardware address pins.
- What is the purpose of the INT pin on the PCA9538APWJ?
The INT pin generates an open-drain active-low interrupt signal when an input port changes state, informing the microcontroller of incoming data without needing to communicate via the I2C bus.
- What is the maximum standby current consumption of the PCA9538APWJ?
The maximum standby current consumption is 1 μA.
- Does the PCA9538APWJ have ESD protection?
Yes, the device has ESD protection exceeding JESD 22 and JESD 78 standards.
- What is the maximum output current capability per I/O and total for the P port?
Each I/O can source up to 25 mA, and the total current for the P port is limited to 200 mA.
- What are the available package options for the PCA9538APWJ?
The device is available in SSOP (16), TVSOP (16), SOIC (16), and TSSOP (16) packages.
- Can the PCA9538APWJ directly drive LEDs?
Yes, the latched outputs have high-current drive capability for directly driving LEDs.
- How does the PCA9538APWJ handle power-up configuration?
The device powers up with all channels configured as inputs and has no glitch on power-up).
