Overview
The PCA9539, produced by Texas Instruments, is a 16-bit I2C and SMBus low-power I/O expander designed for remote I/O expansion in various microcontroller systems. It operates within a voltage range of 2.3 V to 5.5 V and is compatible with most microcontroller families via the I2C interface. The device features low standby current consumption, making it suitable for power-sensitive applications. It includes several key registers such as Configuration, Input Port, Output Port, and Polarity Inversion registers, allowing for flexible configuration and control of the I/O ports.
Key Specifications
| Parameter | Value | Conditions |
|---|---|---|
| Operating Voltage (VCC) | 2.3 V to 5.5 V | |
| Standby Current | 1 μA max | VI = GND, IO = 0, I/O = inputs, fSCL = 0 kHz |
| Operating Current | 100 μA (5.5 V), 30 μA (3.6 V), 20 μA (2.7 V) | VI = VCC or GND, IO = 0, I/O = inputs, fSCL = 400 kHz |
| I2C Bus Frequency | 400 kHz | |
| Output Current (High) | -10 mA | |
| Output Current (Low) | 25 mA | |
| Operating Temperature | -40°C to 85°C | |
| ESD Protection | 2000-V Human-body model, 1000-V Charged-device model | |
| Package Options | SSOP (24), TVSOP (24), SOIC (24), TSSOP (24), VQFN (24) |
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
- Compatible with most microcontrollers
- 400-kHz Fast I2C Bus
- Polarity inversion register
- Address by two hardware address pins for use of up to four devices
- Latched outputs with high-current drive capability for directly driving LEDs
- ESD protection exceeds JESD 22 standards
Applications
The PCA9539 is suitable for a variety of applications requiring remote I/O expansion, including industrial control systems, consumer electronics, and automotive systems. It is particularly useful in scenarios where additional I/O ports are needed without increasing the complexity of the main microcontroller. The device's low power consumption and high ESD protection make it ideal for use in battery-powered devices and harsh environments.
Q & A
- What is the operating voltage range of the PCA9539?
The PCA9539 operates within a voltage range of 2.3 V to 5.5 V. - What is the maximum standby current consumption of the PCA9539?
The maximum standby current consumption is 1 μA. - What is the I2C bus frequency supported by the PCA9539?
The PCA9539 supports a 400 kHz I2C bus frequency. - Can the PCA9539 drive LEDs directly?
Yes, the PCA9539 has latched outputs with high-current drive capability for directly driving LEDs. - How many devices can be addressed using the PCA9539?
Up to four devices can be addressed using the two hardware address pins. - What type of ESD protection does the PCA9539 offer?
The PCA9539 offers ESD protection exceeding JESD 22 standards, including 2000-V Human-body model and 1000-V Charged-device model. - What is the purpose of the open-drain active-low interrupt output?
The open-drain active-low interrupt output is used to indicate to the system master that an input state has changed. - How does the PCA9539 handle power-on reset?
The PCA9539 has an internal power-on reset that holds the device in a reset condition until VCC reaches the power-on reset threshold. - Can the PCA9539 be reset without de-powering the device?
Yes, the PCA9539 can be reset by asserting a low on the RESET input without de-powering the device. - What are the package options available for the PCA9539?
The PCA9539 is available in SSOP (24), TVSOP (24), SOIC (24), TSSOP (24), and VQFN (24) packages.
