SI8440BB-C-ISR Digital Isolator Equivalent & Substitute Parts

Part Overview

The SI8440BB-C-ISR is a general purpose digital isolator manufactured by Skyworks Solutions Inc., featuring 4-channel capacitive coupling isolation with 2500Vrms isolation voltage and 150Mbps data rate in a 16-SOIC package. This device is classified as "Not For New Designs," indicating it has reached end-of-life status. Finding equivalent substitute parts is necessary for ongoing production support, maintenance applications, and designs requiring compatible pin-compatible or functionally equivalent alternatives.

Substiute Parts

SI8440BB-C-ISR

Skyworks Solutions Inc.In Stock: 6230SI8440BB-C-ISR Datasheet

Current PartRFQ

SI8640BB-B-ISR

Skyworks Solutions Inc.In Stock: 108270SI8640BB-B-ISR Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SI8440BB-C-ISR is determined by the following critical parameters:

Core Compatibility Criteria:

• Number of channels: 4 channels required
• Isolation voltage: 2500Vrms minimum
• Package type: 16-SOIC (0.295", 7.50mm Width) for mechanical compatibility
• Data rate: 150Mbps minimum
• Technology: Capacitive coupling isolation
• Channel configuration: Unidirectional, 4 inputs on Side 1, 0 inputs on Side 2
• Supply voltage range: Must accommodate 2.7V minimum operation
• Operating temperature range: -40°C ~ 125°C

The SI8640BB-B-ISR qualifies as a direct substitute based on matching all core compatibility parameters while offering enhanced performance characteristics in specific areas.

Parameter Comparison

Engineering Selection Recommendations

SI8640BB-B-ISR as Primary Substitute:

The SI8640BB-B-ISR is the qualified substitute for SI8440BB-C-ISR applications. This recommendation is based on:

• Product Status Advantage: SI8640BB-B-ISR carries Active product status, ensuring continued manufacturing support and availability, whereas SI8440BB-C-ISR is Not For New Designs.
• Pin Compatibility: Identical 16-SOIC package footprint enables direct PCB replacement without layout modifications.
• Electrical Compatibility: All critical isolation and safety parameters match or exceed the original part specifications.
• Compliance Alignment: Both parts maintain identical RoHS3 compliance, ECCN classification, and HTSUS coding, ensuring regulatory consistency.
• Performance Trade-offs: The substitute exhibits improved CMTI (35kV/µs vs. 25kV/µs) but with slightly increased propagation delay (13ns vs. 9.5ns) and pulse width distortion (4.5ns vs. 2.5ns). These timing differences must be evaluated against specific application timing requirements.
• Supply Voltage Flexibility: SI8640BB-B-ISR supports operation down to 2.5V, providing additional design margin compared to the 2.7V minimum of the original part.

Frequently Asked Questions (FAQ)

Q: Can SI8640BB-B-ISR be used as a direct replacement for SI8440BB-C-ISR in existing designs?

A: Yes, SI8640BB-B-ISR is pin-compatible and functionally equivalent for the core isolation function. However, timing-sensitive applications must verify that the increased propagation delay (13ns vs. 9.5ns) and pulse width distortion (4.5ns vs. 2.5ns) do not violate system timing constraints.

Q: What is the primary reason to switch from SI8440BB-C-ISR to SI8640BB-B-ISR?

A: SI8440BB-C-ISR is classified as "Not For New Designs," indicating end-of-life status. SI8640BB-B-ISR is an Active product with ongoing manufacturing support and availability, making it the appropriate choice for production continuity.

Q: Are the package dimensions identical between these two parts?

A: Yes, both parts use the 16-SOIC (0.295", 7.50mm Width) package. PCB footprints are mechanically and electrically compatible without modification.

Q: Does SI8640BB-B-ISR meet the same isolation voltage requirement?

A: Yes, both parts provide 2500Vrms isolation voltage and are suitable for applications requiring this isolation level.

Q: What is the significance of the improved CMTI in SI8640BB-B-ISR?

A: The SI8640BB-B-ISR offers 35kV/µs CMTI compared to 25kV/µs in SI8440BB-C-ISR. This enhanced common mode transient immunity provides better noise rejection in high-speed switching environments, though it is not required for basic functional compatibility.

Q: Are there any supply voltage differences that affect circuit design?

A: SI8640BB-B-ISR supports a minimum supply voltage of 2.5V versus 2.7V for SI8440BB-C-ISR. This provides additional design flexibility for low-voltage applications but does not prevent substitution in designs operating at 2.7V or higher.

Q: What packaging formats are available for SI8640BB-B-ISR?

A: SI8640BB-B-ISR is supplied in Cut Tape (CT) and Digi-Reel® packaging, whereas SI8440BB-C-ISR was supplied in Tape & Reel (TR) format. Verify packaging compatibility with your procurement and assembly processes.