PCA9555DB I/O Expander 16-Bit I2C/SMBus Interface

Part Overview

The PCA9555DB is a 16-bit I/O expander designed for I2C and SMBus communication at 400 kHz clock frequency. Manufactured by Texas Instruments, this device operates across a supply voltage range of 2.3V to 5.5V and supports an operating temperature range of -40°C to 85°C. The component is housed in a 24-SSOP surface mount package with push-pull output configuration and power-on reset (POR) functionality.

The PCA9555DB is classified as obsolete. Identifying equivalent and substitute parts is necessary to ensure design continuity, maintain supply chain reliability, and support long-term product availability for applications requiring 16-bit I/O expansion with I2C/SMBus interface capability.

Substiute Parts

PCA9555DB

Texas InstrumentsIn Stock: 2577PCA9555DB Datasheet

Current PartRFQ

MAX7312AAG+T

Analog Devices Inc./Maxim IntegratedIn Stock: 664MAX7312AAG+T Datasheet

MFR RecommendedRFQ

PCA9555DB,118

NXP USA Inc.In Stock: 3379PCA9555DB,118 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the PCA9555DB are identified based on strict electrical and mechanical compatibility criteria. The following parameters define valid substitution:

• I/O Count: Must be 16 bits
• Interface Protocol: Must support I2C and SMBus
• Clock Frequency: Must operate at 400 kHz
• Package Type: Must be 24-SSOP with identical 0.209" (5.30mm) width
• Output Configuration: Must be push-pull type
• Interrupt Output: Must be present
• Power-On Reset Feature: Must be included
• Surface Mount Mounting: Required
• RoHS3 Compliance: Required
• MSL Rating: Must be 1 (Unlimited)

Two substitute parts meet these criteria: the MAX7312AAG+T (Analog Devices Inc./Maxim Integrated) and the PCA9555DB,118 (NXP USA Inc.). Both maintain functional and mechanical equivalence to the original PCA9555DB while offering different supply voltage ranges and operating temperature specifications.

Parameter Comparison

Engineering Selection Recommendations

PCA9555DB,118 (NXP USA Inc.) is the direct functional equivalent. This variant maintains identical electrical specifications to the original PCA9555DB, including voltage supply range (2.3V ~ 5.5V), operating temperature range (-40°C ~ 85°C), and output current ratings (10mA, 25mA). The part is currently in active production status, ensuring supply chain continuity. It is available in Cut Tape and Digi-Reel packaging formats and carries ROHS3 compliance with MSL 1 rating.

MAX7312AAG+T (Analog Devices Inc./Maxim Integrated) is a functional substitute with enhanced specifications. This device extends the operating temperature range to -40°C ~ 125°C and provides higher output current capability (31mA, 43mA source/sink). The minimum supply voltage is 2V, which is 0.3V lower than the original specification. The MAX7312AAG+T is actively manufactured and available in Tape & Reel packaging. Selection of this part is appropriate for applications requiring extended temperature operation or higher output drive capability, provided the lower minimum supply voltage is compatible with the system design.

Both substitute parts maintain identical I/O count, interface protocol, clock frequency, package geometry, and compliance certifications as the original PCA9555DB.

Frequently Asked Questions (FAQ)

Q: Can the MAX7312AAG+T be used as a direct replacement for the PCA9555DB in all applications?

A: The MAX7312AAG+T is functionally compatible for I2C/SMBus communication and I/O expansion. However, it provides higher output current capability (31mA, 43mA versus 10mA, 25mA) and extended operating temperature range (-40°C ~ 125°C versus -40°C ~ 85°C). Applications operating at the upper temperature limit of 85°C or requiring the specific 10mA/25mA output current specification should verify compatibility with the enhanced specifications.

Q: What is the difference between PCA9555DB and PCA9555DB,118?

A: Both parts are based on the PCA9555 base product number and share identical electrical and mechanical specifications. The primary difference is packaging format: PCA9555DB,118 is supplied in Cut Tape and Digi-Reel formats by NXP, while the original PCA9555DB may have different packaging availability. The PCA9555DB,118 is currently in active production.

Q: Are all substitute parts available in the same package type?

A: Yes. All three parts—PCA9555DB, MAX7312AAG+T, and PCA9555DB,118—are housed in 24-SSOP packages with identical 0.209" (5.30mm) width. This ensures mechanical compatibility for PCB layout and assembly processes. Packaging format (Tape & Reel versus Cut Tape) differs by supplier but does not affect component functionality or footprint.

Q: What compliance certifications apply to these parts?

A: All three parts are ROHS3 compliant, carry MSL 1 (Unlimited) moisture sensitivity rating, and are REACH unaffected. These certifications ensure compliance with environmental and regulatory requirements for electronic component manufacturing and use.

Q: Which substitute part should be selected for new designs?

A: For new designs, either PCA9555DB,118 or MAX7312AAG+T is appropriate. PCA9555DB,118 maintains exact electrical specifications of the original part. MAX7312AAG+T offers enhanced performance with higher output current and extended temperature range. Selection depends on application requirements for output drive capability and operating temperature range.