Overview
The PCF8574AT/3,512 is a versatile 8-bit I/O expander designed by NXP Semiconductors for use with the I²C-bus. This device provides general-purpose remote I/O expansion, making it an essential component in modern electronic systems. It operates via a two-wire bidirectional I²C-bus, utilizing serial clock (SCL) and serial data (SDA) lines. The PCF8574AT/3,512 is particularly useful for expanding the I/O capacity of microcontrollers, allowing for the integration of additional sensors or actuators without the need for more microcontroller pins.
Key Specifications
| Parameter | Value |
|---|---|
| Manufacturer | NXP USA Inc. |
| Package / Case | 16-SOIC (0.295, 7.50mm Width) |
| Interface | I²C, SMBus |
| Supply Voltage | 2.5V to 6V |
| Operating Temperature | -40°C to +85°C |
| Pin Count | 16 |
| Number of Ports | 1 |
| Clock Frequency | 100 kHz |
| Current - Output Source/Sink | 300μA / 25mA |
| ESD Protection | 2000V HBM, 1000V CDM |
| Latch-up Testing | Exceeds 100 mA (JEDEC Standard JESD78) |
Key Features
- I²C Interface: The device features a 100 kHz standard-mode I²C-bus interface, ensuring seamless communication with microcontrollers and other digital systems.
- Quasi-Bidirectional Ports: Eight quasi-bidirectional ports (P0 to P7) that can be independently assigned as inputs or outputs.
- Hardware Address Inputs: Three hardware address inputs allow for up to eight devices to be connected on the same I²C-bus, supporting up to 128 I/Os.
- Interrupt Output: An active LOW open-drain interrupt output (INT) that indicates changes in input state without continuous polling.
- Low Power Consumption: Low standby current consumption (2.5 μA typical), making it suitable for battery-operated devices.
- ESD Protection: Superior ESD protection exceeding 2000V HBM and 1000V CDM, and latch-up testing exceeding 100 mA.
- Latched Outputs: Latched output ports that directly drive LEDs.
Applications
- Microcontroller Expansion: Enhances the I/O capacity of microcontrollers, allowing for the integration of additional sensors or actuators.
- I²C LCD Displays: Extends the usable pins in I²C LCD displays by connecting LCD data pins to the PCF8574T.
- Battery-Operated Devices: Suitable for battery-operated devices due to its low standby current consumption.
- Complex Circuits: Provides electrical resilience and protection in complex circuits, enhancing durability and reliability.
- Real-Time Data Processing: Ensures efficient real-time data processing and management in applications requiring high-speed communication and control.
Q & A
- What is the PCF8574AT/3,512 used for?
The PCF8574AT/3,512 is used for general-purpose remote I/O expansion via the I²C-bus, extending the I/O capacity of microcontrollers.
- What is the operating voltage range of the PCF8574AT/3,512?
The operating voltage range is 2.5V to 6V.
- How many quasi-bidirectional ports does the PCF8574AT/3,512 have?
The device has eight quasi-bidirectional ports (P0 to P7).
- What is the purpose of the interrupt output (INT) on the PCF8574AT/3,512?
The interrupt output indicates changes in input state without the need for continuous polling by the microcontroller.
- What kind of ESD protection does the PCF8574AT/3,512 offer?
The device offers ESD protection exceeding 2000V HBM and 1000V CDM.
- How many devices of the PCF8574AT/3,512 can be connected on the same I²C-bus?
Up to eight devices can be connected on the same I²C-bus, supporting up to 128 I/Os.
- What is the typical standby current consumption of the PCF8574AT/3,512?
The typical standby current consumption is 2.5 μA.
- Can the PCF8574AT/3,512 directly drive LEDs?
Yes, the latched output ports can directly drive LEDs.
- What is the clock frequency of the I²C-bus interface on the PCF8574AT/3,512?
The clock frequency is 100 kHz.
- How do you program the PCF8574AT/3,512?
The device is programmed by connecting it to a microcontroller via the I²C-bus and using the appropriate software to write to or read from the device's registers.
