Overview
The PCA9538PWG4 is an 8-bit I2C and SMBus low-power I/O expander produced by Texas Instruments, although it may be listed under Burr Brown due to historical reasons. 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 with a power supply range from 2.3 V to 5.5 V and supports both 100-kHz (Standard-mode) and 400-kHz (Fast-mode) clock frequencies. The PCA9538PWG4 is particularly useful in applications where additional I/Os are needed for switches, sensors, push-buttons, LEDs, fans, and other similar devices.
Key Specifications
| Parameter | Min | Max | Unit |
|---|---|---|---|
| Power Supply Voltage | 2.3 | 5.5 | V |
| Standby Current Consumption | 1 | μA | |
| I2C Clock Frequency (Standard-mode) | 100 | kHz | |
| I2C Clock Frequency (Fast-mode) | 400 | kHz | |
| Output High Voltage (VCC – VOH) at 25°C | 0.4 | V | |
| Total Current Sourced by All I/Os | 85 | mA | |
| Maximum Current per I/O | 25 | mA | |
| Package Types | SSOP (16), TVSOP (16), SOIC (16), TSSOP (16) |
Key Features
- Low standby current consumption of 1 μA max.
- I2C to parallel port expander.
- Open-drain active-low interrupt output.
- ESD protection exceeds JESD 22 standards.
- Hardware selectable address pins (A0 and A1) allowing up to four devices on the same I2C bus.
- High-current drive capability for directly driving LEDs.
- Interrupt generation on the INT pin whenever an input port changes state.
- Reset feature via RESET pin or power-on reset.
Applications
- Expanding I/O capabilities for microcontrollers and other ICs.
- Control and monitoring of switches, sensors, push-buttons, LEDs, and fans.
- Use in industrial automation, consumer electronics, and automotive systems.
- Implementation in IoT devices requiring additional I/O ports.
Q & A
- What is the power supply voltage range for the PCA9538PWG4?
The PCA9538PWG4 operates with a power supply range from 2.3 V to 5.5 V.
- What are the supported I2C clock frequencies for this device?
The device supports both 100-kHz (Standard-mode) and 400-kHz (Fast-mode) clock frequencies.
- How many devices can be connected on the same I2C bus using the PCA9538PWG4?
Up to four devices can be connected on the same I2C bus using the hardware selectable address pins (A0 and A1).
- What is the purpose of the INT pin on the PCA9538PWG4?
The INT pin generates an interrupt signal whenever an input port changes state, allowing the microcontroller to be informed without continuous polling.
- How can the PCA9538PWG4 be reset?
The device can be reset using the RESET pin or by cycling the power supply to cause a power-on reset.
- What is the maximum current that can be sourced by all I/Os combined?
The total current sourced by all I/Os must be limited to 85 mA.
- What is the maximum current per I/O?
Each I/O must be externally limited to a maximum of 25 mA.
- What types of packages are available for the PCA9538PWG4?
The device is available in SSOP (16), TVSOP (16), SOIC (16), and TSSOP (16) packages.
- Does the PCA9538PWG4 have ESD protection?
Yes, the device has ESD protection that exceeds JESD 22 standards.
- Can the PCA9538PWG4 directly drive LEDs?
Yes, the device outputs have high-current drive capability for directly driving LEDs.
