Overview
The PCF8574T/3,518, manufactured 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 that require additional I/O ports. The PCF8574T/3,518 operates within a voltage range of 2.5 V to 6 V and features eight quasi-bidirectional ports, a 100 kHz I²C-bus interface, three hardware address inputs, and an interrupt output. This component is particularly useful in systems where additional I/O ports are needed without the need for additional microcontroller pins.
Key Specifications
| Parameter | Description |
|---|---|
| Manufacturer | NXP USA Inc. |
| Package Type | SO16 (Small Outline Package, 16 leads, body width 7.5 mm) |
| Packing Method | Reel 13” Q1/T1, Tape & Reel (TR) |
| Minimum Order Quantity | 1000 |
| Operating Voltage | 2.5 V to 6 V |
| I²C-Bus Frequency | 100 kHz |
| Number of I/O Ports | 8 quasi-bidirectional ports |
| Hardware Address Inputs | 3 |
| Interrupt Output | Active LOW open-drain interrupt output |
| Current Consumption | 2.5 µA (typical, static) |
| Temperature Range | -40°C to +85°C |
Key Features
- Eight quasi-bidirectional I/O ports that can be independently assigned as inputs or outputs.
- 100 kHz I²C-bus interface for communication with the system master.
- Three hardware address inputs allowing up to 16 devices on the same I²C-bus, supporting up to 128 I/Os.
- Active LOW open-drain interrupt output to indicate changes in input state without continuous polling.
- Low current consumption of 2.5 µA (typical, static), suitable for mobile applications.
- Latched output ports that directly drive LEDs.
- Internal Power-On Reset (POR) initializes I/Os as inputs with a weak internal pull-up current source.
Applications
- LED signs and displays
- Servers
- Key pads
- Industrial control systems
- Medical equipment
- PLC (Programmable Logic Controllers)
- Cellular telephones
- Mobile devices
- Gaming machines
- Instrumentation and test measurement equipment
Q & A
- What is the PCF8574T/3,518 used for?
The PCF8574T/3,518 is used for general-purpose remote I/O expansion via the two-wire bidirectional I²C-bus.
- What is the operating voltage range of the PCF8574T/3,518?
The operating voltage range is 2.5 V to 6 V.
- How many I/O ports does the PCF8574T/3,518 have?
The device has eight quasi-bidirectional I/O ports.
- What is the I²C-bus frequency of the PCF8574T/3,518?
The I²C-bus frequency is 100 kHz.
- How many devices of the same type can be on the same I²C-bus?
Up to 16 devices of the same type can be on the same I²C-bus, supporting up to 128 I/Os.
- What is the purpose of the interrupt output on the PCF8574T/3,518?
The interrupt output is used to indicate to the microcontroller that an input state has changed, eliminating the need for continuous polling.
- What is the typical current consumption of the PCF8574T/3,518 in static mode?
The typical current consumption in static mode is 2.5 µA.
- What is the temperature range of the PCF8574T/3,518?
The temperature range is -40°C to +85°C.
- How are the I/O ports initialized after a power-on reset?
The I/O ports are initialized as inputs with a weak internal pull-up current source after a power-on reset.
- What types of applications can the PCF8574T/3,518 be used in?
The PCF8574T/3,518 can be used in various applications such as LED signs, servers, keypads, industrial control systems, medical equipment, and more.
