PCF8574APW Texas Instruments io-expanders (TSSOP-20) In Stock
PCF8574APW is an 8-bit I2C I/O expander by Texas Instruments, supporting 2.5V to 6V supply and 400kHz Fast-mode I2C. From $0.90/unit, in-stock, 1-piece MOQ, worldwide shipping.
- Manufacturer
- Texas Instruments
- Package
- TSSOP-20
- Pin Count
- 20
- Lifecycle
- ACTIVE
- Datasheet
- PCF8574APW Datasheet PDF
- Category
- io-expanders
- Price
- From $0.8988(MOQ 1)
- Temp Range
- -40.0°C to 85.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Applications
Widely used in embedded systems to expand GPIO on microcontrollers for driving LEDs, keypads, and relay boards. Also found in industrial HMI panels, home automation controllers, and smart meter display modules where I2C bus GPIO extension is needed.
Specifications
| supplyVoltage | 2.5V to 6V |
| interface | I2C / SMBus |
| maxClockFrequency | 400 kHz |
| ioPins | 8 |
| operatingTemperature | -40 to +85 |
| packageType | TSSOP-20 |
| pitch | 0.65 mm |
| addressableDevices | 8 per bus |
| interruptOutput | Yes (active-low) |
| Package | TSSOP-20 |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
Alternate & Equivalent Parts
Compatible alternatives and drop-in replacements for PCF8574APW:
Same 8-bit I2C I/O expander, different I2C address range (0x20-0x27 vs 0x38-0x3F)
8-bit I2C I/O expander with open-drain interrupt, 1.65V to 5.5V, TSSOP-16
Frequently Asked Questions
What is the PCF8574APW and what does it do?
The PCF8574APW is an 8-bit I2C-bus I/O port expander from Texas Instruments. It connects to a microcontroller via a 2-wire I2C interface (SDA/SCL) and provides 8 quasi-bidirectional I/O pins that can individually read or drive digital signals. It operates from 2.5V to 6V and supports I2C speeds up to 400kHz, making it ideal for expanding GPIO when a microcontroller runs out of I/O pins.
How many PCF8574APW devices can I connect to the same I2C bus?
Up to 8 PCF8574APW devices can share the same I2C bus. The device features 3 hardware address pins (A0, A1, A2), each tied high or low to set a unique 7-bit I2C address, giving 8 possible addresses. With 8 devices you can control up to 64 independent I/O pins over just 2 wires.
What is the difference between PCF8574APW and PCF8574PW?
Both are 8-bit I2C I/O expanders in the TSSOP-20 package. The key difference is the I2C base address range: PCF8574A (suffix A) uses addresses 0x38 to 0x3F, while PCF8574 (no A suffix) uses 0x20 to 0x27. This lets you mix both variants on one bus for up to 16 expander devices (128 I/O pins) simultaneously.
What supply voltage and logic levels does the PCF8574APW support?
The PCF8574APW operates from 2.5V to 6V. Its I/O pins are quasi-bidirectional with internal pull-ups, and logic levels track the supply voltage, making it compatible with both 3.3V and 5V microcontrollers without level-shifting in most designs.
What are the typical applications for the PCF8574APW?
Common applications include GPIO expansion for MCUs driving LED arrays, 4x4 keypads, relay modules, and LCD displays; industrial control panels requiring isolated I/O; home automation nodes; smart meters and energy monitors; and any battery-powered design where minimizing microcontroller I/O pin count reduces system cost.
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About Texas Instruments
Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
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