PCA9557DB Equivalent & Substitute Parts

Part Overview

The PCA9557DB is an 8-bit I/O expander designed for I2C and SMBus communication at 400 kHz, packaged in a 16-SSOP surface mount configuration. This device is classified as obsolete, making substitute parts necessary for new designs and ongoing production requirements. The PCA9557DB provides open drain and push-pull output options with a supply voltage range of 2.3V to 5.5V and operates across the industrial temperature range of -40°C to 85°C.

Substiute Parts

PCA9557DB

Texas InstrumentsIn Stock: 2177PCA9557DB Datasheet

Current PartRFQ

PCA9557PWR

Texas InstrumentsIn Stock: 30955PCA9557PWR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the PCA9557DB is determined by functional and electrical equivalence across the following criteria:

• I/O Configuration: 8-bit I/O expander functionality
• Communication Protocol: I2C and SMBus compatibility at 400 kHz
• Output Characteristics: Open drain and push-pull output capability
• Electrical Performance: Current sourcing/sinking of 10mA and 25mA
• Supply Voltage Range: 2.3V to 5.5V operation
• Temperature Range: -40°C to 85°C operating specification
• Compliance: ROHS3 compliance and REACH unaffected status
• Base Product Number: PCA9557 series designation

The primary distinction between the main part and its substitute relates to packaging format and product status. The PCA9557DB uses 16-SSOP packaging and is obsolete, while the substitute maintains electrical equivalence with alternative packaging and active product status.

Parameter Comparison

Engineering Selection Recommendations

The PCA9557PWR serves as the direct functional equivalent to the PCA9557DB. Both devices maintain identical electrical specifications, communication protocols, and performance characteristics across all operating conditions. The PCA9557PWR is the manufacturer-recommended substitute, offering the advantage of active product status with established supply chain availability.

The primary design consideration is the package transition from 16-SSOP to 16-TSSOP. The 16-TSSOP package is narrower (4.40mm versus 5.30mm), which may require PCB layout modifications. Both packages are surface mount configurations with equivalent pin counts and functionality.

Selection of the PCA9557PWR is appropriate for new designs, production continuations, and legacy system updates. The active product status ensures long-term availability and manufacturing support. Both devices maintain ROHS3 compliance and REACH unaffected status, satisfying regulatory requirements.

Frequently Asked Questions (FAQ)

Q: Are the PCA9557DB and PCA9557PWR electrically identical?

A: Yes. Both devices provide 8-bit I/O expansion with I2C and SMBus 400 kHz communication, identical output types, current ratings, supply voltage ranges, and operating temperature specifications. Electrical functionality is equivalent.

Q: What is the primary difference between these parts?

A: The main differences are packaging format and product status. The PCA9557DB uses 16-SSOP packaging and is obsolete. The PCA9557PWR uses 16-TSSOP packaging and maintains active product status.

Q: Can I use PCA9557PWR as a direct replacement in existing designs?

A: Functional replacement is direct. However, the narrower 16-TSSOP package (4.40mm width versus 5.30mm) requires PCB layout verification. Pin configuration and functionality remain identical, but physical footprint dimensions differ.

Q: Are there supply chain differences between these parts?

A: The PCA9557PWR has significantly higher inventory availability (30,882 pieces) compared to the PCA9557DB (2,100 pieces). The active product status of the PCA9557PWR ensures continued manufacturing and distribution support.

Q: Do both parts meet the same compliance standards?

A: Yes. Both the PCA9557DB and PCA9557PWR are ROHS3 compliant, REACH unaffected, and carry identical moisture sensitivity levels (MSL 1 - Unlimited).

Q: What packaging format should I specify for new designs?

A: The PCA9557PWR with 16-TSSOP packaging is the recommended selection for new designs, as it maintains active product status and manufacturer support.