PCF8575DW Equivalent & Substitute Parts

Part Overview

The PCF8575DW is a 16-bit I/O expander interface IC designed for I2C and SMBus communication at 400 kHz, housed in a 24-SOIC package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. The PCF8575DW provides push-pull output capability with interrupt functionality and power-on reset features, suitable for applications requiring expanded digital I/O control over I2C bus architecture.

Key Parameters

Parameter	PCF8575DW Value
Number of I/O	16
Interface	I2C, SMBus
Clock Frequency	400 kHz
Voltage Supply Range	4.5V ~ 5.5V
Output Type	Push-Pull
Interrupt Output	Yes
Operating Temperature	-40°C ~ 85°C
Package Type	24-SOIC
Current Output Source/Sink	10mA, 25mA
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the PCF8575DW is determined by strict alignment of the following electrical and mechanical parameters:

Primary Substitution Criteria:

16-bit I/O configuration
I2C interface at 400 kHz clock frequency
Push-pull output type with interrupt capability
Power-on reset (POR) feature
24-SOIC package form factor
Supply voltage compatibility (minimum 4.5V operation required for direct drop-in replacement)

Secondary Considerations:

Operating temperature range (PCF8575DW: -40°C ~ 85°C)
Output current drive capability (10mA minimum source, 25mA sink)
RoHS3 compliance and MSL rating

Substitute parts are grouped into two categories:

Category 1: Direct Pin-Compatible Replacements (24-SOIC Package) PCF8575DWR, MAX7311AWG+, MAX7311AWG+T, MAX7312AWG+T, MAX7318AWG+T — These parts maintain identical pinout and 24-SOIC packaging, supporting the full 4.5V ~ 5.5V supply range required by the original design.

Category 2: Functional Equivalents (Alternative Packages) MAX7326AEG+T (24-QSOP), MCP23016 series (28-QFN, 28-SPDIP, 28-SSOP, 28-SOIC) — These parts provide equivalent I/O expansion functionality with 16-bit I2C interface but require PCB layout and pinout redesign due to different package geometries.

Parameter Comparison

Part Number	Manufacturer	I/O Count	Interface	Clock Freq	Supply Voltage	Output Type	Interrupt	Temp Range	Package	Status
PCF8575DW	Texas Instruments	16	I2C, SMBus	400 kHz	4.5V ~ 5.5V	Push-Pull	Yes	-40°C ~ 85°C	24-SOIC	Obsolete
PCF8575DWR	Texas Instruments	16	I2C, SMBus	400 kHz	2.5V ~ 5.5V	Push-Pull	Yes	-40°C ~ 85°C	24-SOIC	Active
MAX7311AWG+	Analog Devices Inc./Maxim Integrated	16	I2C, SMBus	400 kHz	2V ~ 5.5V	Push-Pull	Yes	-40°C ~ 125°C	24-SOIC	Active
MAX7311AWG+T	Analog Devices Inc./Maxim Integrated	16	I2C, SMBus	400 kHz	2V ~ 5.5V	Push-Pull	Yes	-40°C ~ 125°C	24-SOIC	Active
MAX7312AWG+T	Analog Devices Inc./Maxim Integrated	16	I2C, SMBus	400 kHz	2V ~ 5.5V	Push-Pull	Yes	-40°C ~ 125°C	24-SOIC	Active
MAX7318AWG+T	Analog Devices Inc./Maxim Integrated	16	I2C, SMBus	400 kHz	2V ~ 5.5V	Push-Pull	Yes	-40°C ~ 125°C	24-SOIC	Active
MAX7326AEG+T	Analog Devices Inc./Maxim Integrated	16	I2C	400 kHz	1.71V ~ 5.5V	Push-Pull	Yes	-40°C ~ 125°C	24-QSOP	Active
MCP23016-I/ML	Microchip Technology	16	I2C	400 kHz	2V ~ 5.5V	Push-Pull	Yes	-40°C ~ 85°C	28-QFN	Active
MCP23016-I/SP	Microchip Technology	16	I2C	400 kHz	2V ~ 5.5V	Push-Pull	Yes	-40°C ~ 85°C	28-SPDIP	Active
MCP23016-I/SS	Microchip Technology	16	I2C	400 kHz	2V ~ 5.5V	Push-Pull	Yes	-40°C ~ 85°C	28-SSOP	Active
MCP23016T-I/SO	Microchip Technology	16	I2C	400 kHz	2V ~ 5.5V	Push-Pull	Yes	-40°C ~ 85°C	28-SOIC	Active

Engineering Selection Recommendations

For Direct Replacement (No PCB Redesign Required):

PCF8575DWR is the manufacturer-recommended successor from Texas Instruments, maintaining identical 24-SOIC pinout and electrical interface. This part is active in production with expanded supply voltage range (2.5V ~ 5.5V) and is RoHS3 compliant with MSL-1 rating.

MAX7311AWG+, MAX7311AWG+T, MAX7312AWG+T, and MAX7318AWG+T from Analog Devices Inc./Maxim Integrated are pin-compatible alternatives in 24-SOIC packaging. These parts support extended operating temperature range (-40°C ~ 125°C) and lower minimum supply voltage (2V). All are active products with RoHS3 compliance and MSL-1 rating.

For Functional Equivalence (PCB Redesign Required):

MAX7326AEG+T provides 16-bit I2C I/O expansion in a more compact 24-QSOP package with the widest supply voltage range (1.71V ~ 5.5V) and extended temperature capability (-40°C ~ 125°C). Suitable for space-constrained applications where pinout redesign is acceptable.

MCP23016 series (Microchip Technology) offers multiple package options: 28-QFN (MCP23016-I/ML), 28-SPDIP (MCP23016-I/SP), 28-SSOP (MCP23016-I/SS), and 28-SOIC (MCP23016T-I/SO). All variants provide 16-bit I2C interface at 400 kHz with 25mA output drive capability. The 28-SPDIP variant offers through-hole mounting for legacy assembly processes. All MCP23016 variants are active products with RoHS3 compliance and MSL-1 rating.

All substitute parts listed maintain RoHS3 compliance and REACH unaffected status, matching the original PCF8575DW regulatory requirements.

Frequently Asked Questions (FAQ)

Q: Can PCF8575DWR be used as a direct drop-in replacement for PCF8575DW?

A: Yes. PCF8575DWR maintains identical pinout, 24-SOIC package geometry, and I2C/SMBus interface specifications. The primary difference is expanded supply voltage range (2.5V ~ 5.5V vs. 4.5V ~ 5.5V) and active product status. Designs operating at 4.5V ~ 5.5V require no modifications.

Q: What is the key difference between MAX7311 and MAX7312 variants?

A: Both MAX7311AWG+ and MAX7312AWG+T are functionally equivalent 16-bit I2C I/O expanders in 24-SOIC packaging with identical electrical specifications. The difference lies in packaging format: MAX7311AWG+ is supplied in Tube packaging, while MAX7312AWG+T is supplied in Tape & Reel format. Selection depends on procurement and assembly requirements.

Q: Why do MCP23016 parts have different package designations (28-QFN, 28-SOIC, 28-SSOP, 28-SPDIP)?

A: MCP23016 is available in multiple package options to accommodate different PCB assembly technologies and space constraints. The 28-SOIC (MCP23016T-I/SO) is the closest surface-mount equivalent to the 24-SOIC PCF8575DW, though it requires pinout redesign. The 28-SPDIP (MCP23016-I/SP) supports through-hole assembly for legacy manufacturing processes.

Q: Is MAX7326AEG+T compatible with PCF8575DW designs?

A: MAX7326AEG+T provides equivalent 16-bit I2C I/O expansion functionality but uses a 24-QSOP package instead of 24-SOIC. This requires PCB layout and schematic redesign. The part is suitable for new designs where package footprint optimization is a priority.

Q: What supply voltage range should I use when substituting with MAX7311 or MAX7312 series?

A: MAX7311 and MAX7312 series support 2V ~ 5.5V supply range. For designs originally specified at 4.5V ~ 5.5V (PCF8575DW), operation within this range is fully supported. Lower voltage operation (2V ~ 4.5V) is possible but requires verification that all system components support this range.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed (PCF8575DWR, MAX7311 series, MAX7312 series, MAX7318 series, MAX7326 series, and MCP23016 series) are RoHS3 compliant with MSL-1 moisture sensitivity rating, matching the original PCF8575DW regulatory status.

Q: Which substitute part has the highest inventory availability?

A: MAX7312AWG+T has the highest inventory at 60,400 pieces in stock. PCF8575DWR has 6,326 pieces, and MAX7311AWG+ has 29,945 pieces available. MCP23016-I/SP has the largest inventory among Microchip options at 1,000,399 pieces.

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