Overview
The PCF8574TS/3,118, produced by NXP USA Inc., is a remote 8-bit I/O expander designed for use with the two-wire bidirectional I²C-bus. This device provides general-purpose remote I/O expansion, making it suitable for a variety of applications requiring additional I/O ports. The PCF8574TS is part of the PCF8574/74A series, which are identical except for the different fixed portion of the slave address.
Key Specifications
| Parameter | Description |
|---|---|
| Interface Type | I²C-bus (100 kHz) |
| No. of I/O's | 8 quasi-bidirectional ports |
| Supply Voltage Range | 2.5 V to 6 V |
| Digital IC Case Style | SSOP-20 |
| No. of Pins | 20 |
| Operating Temperature Range | -40°C to +85°C |
| Interrupt Output | Active LOW open-drain interrupt output |
| Hardware Address Inputs | Three hardware address inputs |
| Power-On Reset (POR) | Initializes I/Os as inputs with a weak internal pull-up 100 µA current source |
| Current Consumption | Typical static current consumption of 2.5 µA |
Key Features
- Provides general-purpose remote I/O expansion via the I²C-bus.
- Eight quasi-bidirectional ports that can be independently assigned as inputs or outputs.
- Supports up to 16 devices on the same I²C-bus, allowing for up to 128 I/Os.
- Active LOW open-drain interrupt output to indicate changes in input state.
- Low current consumption, making it suitable for mobile applications.
- Latched output ports directly drive LEDs.
- Three hardware address inputs for device addressing.
- Power-On Reset (POR) initializes I/Os as inputs with a weak internal pull-up.
Applications
- Expanding the I/O capability of microcontrollers in various embedded systems.
- Mobile applications due to low current consumption.
- Industrial control systems requiring additional I/O ports.
- Automotive systems for monitoring and controlling various parameters.
- Consumer electronics for adding more functionality without increasing the microcontroller's pin count.
Q & A
- What is the primary function of the PCF8574TS?
The primary function of the PCF8574TS is to provide general-purpose remote I/O expansion via the two-wire bidirectional I²C-bus.
- How many quasi-bidirectional ports does the PCF8574TS have?
The PCF8574TS has eight quasi-bidirectional ports.
- What is the operating voltage range of the PCF8574TS?
The operating voltage range is from 2.5 V to 6 V.
- What is the maximum number of PCF8574TS devices that can be connected on the same I²C-bus?
Up to 16 devices can be connected on the same I²C-bus, supporting up to 128 I/Os.
- What is the purpose of the interrupt output on the PCF8574TS?
The interrupt output is used to indicate to the microcontroller that an input state has changed, eliminating the need for continuous polling.
- How does the Power-On Reset (POR) function on the PCF8574TS?
The POR initializes the I/Os as inputs with a weak internal pull-up 100 µA current source.
- What is the typical static current consumption of the PCF8574TS?
The typical static current consumption is 2.5 µA.
- What type of package does the PCF8574TS come in?
The PCF8574TS comes in a SSOP-20 package.
- What is the operating temperature range of the PCF8574TS?
The operating temperature range is from -40°C to +85°C.
- Can the PCF8574TS directly drive LEDs?
