PCA9555PW I/O Expander 16 I2C SMBus 400 kHz Equivalent & Substitute Parts

Part Overview

The PCA9555PW is a 16-bit I/O expander interface circuit designed for I2C and SMBus communication at 400 kHz clock frequency in a 24-TSSOP surface mount package. This Texas Instruments component features push-pull output configuration with 10mA/25mA source/sink current capability and power-on reset functionality. The part is currently listed as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Key Parameters

Parameter	Value
Manufacturer Part Number	PCA9555PW
Manufacturer	Texas Instruments
Number of I/O	16
Interface	I2C, SMBus
Clock Frequency	400 kHz
Output Type	Push-Pull
Current - Output Source/Sink	10mA, 25mA
Voltage - Supply	2.3V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Package / Case	24-TSSOP (0.173", 4.40mm Width)
Product Status	Obsolete
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution for the PCA9555PW is determined by the following critical parameters: 16 I/O count, I2C/SMBus interface support, 400 kHz clock frequency, 24-TSSOP package compatibility, and push-pull output configuration. Substitute parts are grouped into two categories based on these electrical and mechanical constraints:

Category 1: Direct Pin-Compatible Substitutes (24-TSSOP Package, Push-Pull Output) Parts maintaining identical package footprint and push-pull output topology: PCA9535APW,118; PCA9535PW,112; PCA9555PW,112; MAX7311AUG+; MAX7311AUG+T; MAX7318AUG+T

Category 2: Functional Equivalents with Package Variation (24-QSOP Package, Open Drain Output) Parts with different package and output configuration: MAX7313AEG+; MAX7313AEG+T

Category 3: Functional Equivalents with Reduced Parameter Definition Parts with I2C interface and 400 kHz operation in 24-TSSOP package: PI4IOE5V9555LEX

Parameter Comparison

Part Number	Manufacturer	I/O Count	Interface	Clock Frequency	Output Type	Current Source/Sink	Supply Voltage	Operating Temp	Package	Product Status
PCA9555PW	Texas Instruments	16	I2C, SMBus	400 kHz	Push-Pull	10mA, 25mA	2.3V ~ 5.5V	-40°C ~ 85°C	24-TSSOP	Obsolete
MAX7311AUG+	Analog Devices Inc./Maxim Integrated	16	I2C, SMBus	400 kHz	Push-Pull	31mA, 43mA	2V ~ 5.5V	-40°C ~ 125°C	24-TSSOP	Active
MAX7311AUG+T	Analog Devices Inc./Maxim Integrated	16	I2C, SMBus	400 kHz	Push-Pull	31mA, 43mA	2V ~ 5.5V	-40°C ~ 125°C	24-TSSOP	Active
MAX7312AUG+	Analog Devices Inc./Maxim Integrated	16	I2C, SMBus	400 kHz	Push-Pull	31mA, 43mA	2V ~ 5.5V	-40°C ~ 125°C	24-TSSOP	Active
MAX7313AEG+	Analog Devices Inc./Maxim Integrated	16	I2C, SMBus	400 kHz	Open Drain	50mA	2V ~ 3.6V	-40°C ~ 125°C	24-QSOP	Active
MAX7313AEG+T	Analog Devices Inc./Maxim Integrated	16	I2C, SMBus	400 kHz	Open Drain	50mA	2V ~ 3.6V	-40°C ~ 125°C	24-QSOP	Active
MAX7318AUG+T	Analog Devices Inc./Maxim Integrated	16	I2C, SMBus	400 kHz	Push-Pull	31mA, 43mA	2V ~ 5.5V	-40°C ~ 125°C	24-TSSOP	Active
PCA9535APW,118	NXP USA Inc.	16	I2C, SMBus	400 kHz	Push-Pull	10mA, 25mA	1.65V ~ 5.5V	-40°C ~ 85°C	24-TSSOP	Active
PCA9535PW,112	NXP Semiconductors	16	I2C, SMBus	400 kHz	Push-Pull	10mA, 25mA	2.3V ~ 5.5V	-40°C ~ 85°C	24-TSSOP	Active
PCA9555PW,112	NXP Semiconductors	16	I2C, SMBus	400 kHz	Push-Pull	10mA, 25mA	2.3V ~ 5.5V	-40°C ~ 85°C	24-TSSOP	Active
PI4IOE5V9555LEX	Diodes Incorporated	16	I2C	400 kHz	Not Specified	Not Specified	2.3V ~ 5.5V	-40°C ~ 85°C	24-TSSOP	Active

Engineering Selection Recommendations

Primary Substitutes (Highest Compatibility) PCA9535PW,112 and PCA9555PW,112 from NXP Semiconductors are direct functional equivalents with identical electrical specifications, package footprint, and active product status. These parts maintain the same supply voltage range (2.3V ~ 5.5V), output current ratings (10mA/25mA), and operating temperature range (-40°C ~ 85°C) as the original PCA9555PW. Both are ROHS3 compliant with unlimited moisture sensitivity rating.

Secondary Substitutes (Enhanced Performance) MAX7311AUG+, MAX7311AUG+T, MAX7312AUG+, and MAX7318AUG+T from Analog Devices Inc./Maxim Integrated provide superior output current capability (31mA/43mA) and extended operating temperature range (-40°C ~ 125°C). These parts maintain 24-TSSOP package compatibility and push-pull output configuration. Supply voltage range extends to 2V minimum, providing broader system compatibility. All are active products with ROHS3 compliance.

Alternative with Package Consideration MAX7313AEG+ and MAX7313AEG+T feature open-drain output configuration in 24-QSOP package with higher output current (50mA) but narrower supply voltage range (2V ~ 3.6V). These require PCB layout redesign due to package change and are suitable only for systems operating within the specified voltage window.

Functional Equivalent with Limited Specification Data PI4IOE5V9555LEX from Diodes Incorporated maintains 16 I/O count, I2C interface, 400 kHz operation, and 24-TSSOP package. Incomplete parameter definition for output type and current capability requires datasheet review before selection.

Frequently Asked Questions (FAQ)

Q: Can PCA9535PW,112 directly replace PCA9555PW in existing designs? A: Yes. Both parts share identical electrical specifications, package footprint (24-TSSOP), interface protocol (I2C/SMBus 400 kHz), output configuration (push-pull), and operating parameters. No circuit modification is required.

Q: What is the primary advantage of MAX7311AUG+T over PCA9555PW? A: MAX7311AUG+T provides higher output current capability (31mA/43mA versus 10mA/25mA) and extended operating temperature range (-40°C ~ 125°C versus -40°C ~ 85°C) while maintaining identical package and interface specifications. This enables use in higher-current applications and wider temperature environments.

Q: Why are MAX7313AEG+ and MAX7313AEG+T listed as alternatives despite package differences? A: These parts maintain 16 I/O count, I2C/SMBus interface, and 400 kHz operation but use 24-QSOP package instead of 24-TSSOP and feature open-drain output instead of push-pull. They are functional equivalents for applications where package footprint redesign is acceptable and open-drain output topology is compatible with system requirements.

Q: Is PI4IOE5V9555LEX a suitable replacement? A: PI4IOE5V9555LEX maintains core functionality (16 I/O, I2C 400 kHz, 24-TSSOP package, 2.3V ~ 5.5V supply) but lacks complete parameter specification for output type and current capability. Datasheet verification is required before design implementation.

Q: What supply voltage range is common across all substitutes? A: The minimum common supply voltage across all listed substitutes is 2V. The original PCA9555PW and most NXP alternatives specify 2.3V minimum. MAX7313 variants limit operation to 3.6V maximum, restricting use in 5V-only systems.

Q: Are all substitute parts ROHS3 compliant? A: Yes. All listed substitute parts maintain ROHS3 compliance and unlimited moisture sensitivity rating (MSL 1), matching the original PCA9555PW environmental certification status.

Q: Which substitute offers the best thermal performance? A: MAX7311AUG+, MAX7311AUG+T, MAX7312AUG+, and MAX7318AUG+T support extended operating temperature range to 125°C, compared to 85°C maximum for PCA9555PW and NXP alternatives. This provides 40°C additional thermal margin for high-temperature applications.

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