Overview
The PCF8574AP,112, 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 PCF8574AP is identical to the PCF8574, except for the different fixed portion of the slave address, allowing multiple devices to be connected on the same I²C-bus.
Key Specifications
| Specification | Value |
|---|---|
| Operating Supply Voltage | 2.5 V to 6 V |
| I²C-bus Interface | 100 kHz (Standard-mode I²C-bus) |
| Number of I/O Ports | 8 quasi-bidirectional ports |
| Hardware Address Inputs | 3 (allowing 8 programmable slave addresses) |
| Interrupt Output | Active LOW open-drain interrupt output |
| Package Types | DIP16, SO16, SSOP20 |
| Operating Temperature | -40°C to +85°C |
| Standby Current | 2.5 µA (typical, static) |
| ESD Protection | Exceeds 2000 V HBM per JESD22-A114 and 1000 V CDM per JESD22-C101 |
| Total Package Sink Capability | 80 mA |
Key Features
- I²C-bus to parallel port expander
- 8-bit remote I/O pins that default to inputs at power-up
- Latched outputs directly drive LEDs
- Low standby current (2.5 µA typical)
- Active LOW open-drain interrupt output
- Eight programmable slave addresses using three address pins
- Internal Power-On Reset (POR) initializes I/Os as inputs with a weak internal pull-up 100 µA current source
- ESD protection exceeds 2000 V HBM per JESD22-A114 and 1000 V CDM per JESD22-C101
Applications
The PCF8574AP is versatile and can be used in various applications, including:
- Mobile devices due to its low current consumption
- Industrial control systems requiring additional I/O ports
- Automotive systems for expanding I/O capabilities
- Consumer electronics for keypads, LED indicators, and other input/output functions
- Embedded systems where I²C-bus communication is utilized
Q & A
- What is the primary function of the PCF8574AP?
The primary function of the PCF8574AP is to provide general-purpose remote I/O expansion via the two-wire bidirectional I²C-bus. - What is the operating supply voltage range for the PCF8574AP?
The operating supply voltage range is 2.5 V to 6 V. - How many quasi-bidirectional I/O ports does the PCF8574AP have?
The PCF8574AP has 8 quasi-bidirectional I/O ports. - What is the purpose of the three hardware address inputs?
The three hardware address inputs allow for eight programmable slave addresses, enabling multiple devices to be connected on the same I²C-bus. - What is the interrupt output type of the PCF8574AP?
The interrupt output is an active LOW open-drain interrupt output. - What is the typical standby current of the PCF8574AP?
The typical standby current is 2.5 µA. - What is the operating temperature range of the PCF8574AP?
The operating temperature range is -40°C to +85°C. - Does the PCF8574AP have ESD protection?
Yes, it exceeds 2000 V HBM per JESD22-A114 and 1000 V CDM per JESD22-C101. - Can the PCF8574AP directly drive LEDs?
Yes, the latched output ports directly drive LEDs. - How many devices of the PCF8574AP can be connected on the same I²C-bus?
Up to 16 devices (8 of each PCF8574 and PCF8574A) can be connected on the same I²C-bus, supporting up to 128 I/Os.
