PCF8574DW Equivalent & Substitute Parts

Part Overview

The PCF8574DW is an 8-bit I/O expander with I2C interface operating at 100 kHz, manufactured by Texas Instruments in a 16-SOIC surface mount package. This part is classified as obsolete, making equivalent substitutes necessary for new designs and ongoing production requirements. The PCF8574DW provides remote I/O expansion capabilities with push-pull output configuration and power-on reset functionality across industrial temperature ranges.

Substiute Parts

PCF8574DW

Texas InstrumentsIn Stock: 68173PCF8574DW Datasheet

Current PartRFQ

PCF8574DWR

Texas InstrumentsIn Stock: 104771PCF8574DWR Datasheet

MFR RecommendedRFQ

PCF8574T/3,512

NXP USA Inc.In Stock: 2237PCF8574T/3,512 Datasheet

DirectRFQ

PCF8574T/3,518

NXP USA Inc.In Stock: 2285PCF8574T/3,518 Datasheet

DirectRFQ

PCA9554AD,118

NXP USA Inc.In Stock: 3992PCA9554AD,118 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the PCF8574DW is determined by electrical and mechanical compatibility across the following critical parameters: I/O count (8 bits), interface protocol (I2C), output configuration (push-pull), interrupt capability, supply voltage range, operating temperature range, and physical package format (16-SOIC). Substitute parts must maintain functional equivalence in these core specifications.

The substitute parts are grouped into two categories:

Direct Electrical Equivalents (Same Clock Frequency): PCF8574DWR, PCF8574T/3,512, and PCF8574T/3,518 maintain the 100 kHz I2C clock frequency specification, identical to the main part.

Enhanced Functional Equivalent (Higher Clock Frequency): PCA9554AD,118 operates at 400 kHz I2C with SMBus compatibility, providing higher communication speed while maintaining all core I/O expansion functionality and electrical parameters within acceptable ranges.

Parameter Comparison

Engineering Selection Recommendations

PCF8574DWR is the primary substitute, offering identical electrical specifications and active product status from Texas Instruments. This part maintains 100 kHz I2C operation and is available in Cut Tape and Digi-Reel packaging for production flexibility.

PCF8574T/3,512 and PCF8574T/3,518 are direct NXP equivalents with active status. Both maintain 100 kHz I2C clock frequency and identical I/O functionality. The primary difference is packaging: tube format for PCF8574T/3,512 and cut tape/reel for PCF8574T/3,518. Note that source/sink current is specified at 300µA minimum versus 1mA for the original part.

PCA9554AD,118 serves as an enhanced alternative when higher I2C communication speed is acceptable. Operating at 400 kHz with SMBus compatibility, this part expands protocol flexibility while maintaining all core I/O expansion features. Supply voltage range is slightly narrower (2.3V ~ 5.5V versus 2.5V ~ 6V). Source current is specified at 10mA minimum.

All substitute parts maintain ROHS3 compliance and operate across the full -40°C to 85°C industrial temperature range.

Frequently Asked Questions (FAQ)

Q: Can PCF8574DWR directly replace PCF8574DW without circuit modification?

A: Yes. PCF8574DWR maintains identical electrical specifications, pin configuration, and 16-SOIC package format. No circuit changes are required for direct substitution.

Q: What is the difference between PCF8574T/3,512 and PCF8574T/3,518?

A: Both parts are electrically identical NXP equivalents with 100 kHz I2C operation. The difference is packaging: PCF8574T/3,512 is supplied in tube format, while PCF8574T/3,518 is supplied in cut tape and Digi-Reel format for automated assembly.

Q: Can PCA9554AD,118 be used as a drop-in replacement?

A: PCA9554AD,118 is electrically compatible and pin-compatible in the 16-SOIC package. However, it operates at 400 kHz I2C clock frequency instead of 100 kHz, and has a slightly narrower supply voltage range (2.3V ~ 5.5V). Verify that your I2C bus and power supply specifications accommodate these differences before substitution.

Q: Are there differences in source/sink current specifications?

A: Yes. PCF8574DW and PCF8574DWR specify 1mA minimum source current. PCF8574T/3,512 and PCF8574T/3,518 specify 300µA minimum. PCA9554AD,118 specifies 10mA minimum. All parts maintain 25mA sink current. Verify your application's output current requirements before selection.

Q: What is the moisture sensitivity level difference?

A: PCF8574DW and PCF8574DWR have MSL 1 (unlimited shelf life). PCF8574T/3,512 and PCF8574T/3,518 have MSL 2 (1 year shelf life). This affects storage and handling requirements for long-term inventory.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts maintain ROHS3 compliance and REACH unaffected status, matching the original PCF8574DW environmental certifications.