SI8440AB-C-IS1R Digital Isolator Equivalent & Substitute Parts

Part Overview

The SI8440AB-C-IS1R is a general purpose digital isolator manufactured by Skyworks Solutions Inc., featuring 2500Vrms isolation voltage and 4-channel unidirectional configuration. This component utilizes capacitive coupling technology and operates across a supply voltage range of 2.7V to 5.5V with a 1Mbps data rate.

The SI8440AB-C-IS1R carries a product status of "Not For New Designs," indicating it is obsolete or in end-of-life phase. This status necessitates identification of functionally equivalent alternatives for ongoing production requirements and new design implementations.

Substiute Parts

SI8440AB-C-IS1R

Skyworks Solutions Inc.In Stock: 1173SI8440AB-C-IS1R Datasheet

Current PartRFQ

SI8640AB-B-IS1R

Skyworks Solutions Inc.In Stock: 936SI8640AB-B-IS1R Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SI8440AB-C-IS1R is determined by the following critical parameters:

• Isolation voltage rating of 2500Vrms or higher
• 4-channel configuration with unidirectional input topology (4 inputs / 0 outputs)
• 1Mbps data rate capability
• 16-SOIC package compatibility
• Capacitive coupling technology
• Operating temperature range of -40°C to 125°C
• Supply voltage compatibility within or overlapping the 2.7V ~ 5.5V range

The SI8640AB-B-IS1R meets all substitution criteria and represents a direct functional equivalent with enhanced performance characteristics in specific parameters.

Parameter Comparison

Engineering Selection Recommendations

The SI8640AB-B-IS1R is the recommended substitute for the SI8440AB-C-IS1R based on the following engineering criteria:

Product Status Alignment: The SI8640AB-B-IS1R maintains Active product status, ensuring continued manufacturer support, availability, and compliance with current design standards. The original SI8440AB-C-IS1R is designated "Not For New Designs," making transition to an active alternative necessary for long-term supply chain viability.

Functional Equivalence: Both devices share identical isolation voltage (2500Vrms), channel configuration (4-channel unidirectional), data rate (1Mbps), package format (16-SOIC), and operating temperature range (-40°C to 125°C). Pin-level compatibility and functional behavior are preserved.

Performance Enhancement: The SI8640AB-B-IS1R provides improved Common Mode Transient Immunity (35kV/µs versus 25kV/µs) and faster rise/fall times (2.5ns versus 3.8ns/2.8ns), delivering superior noise immunity and signal integrity in high-speed switching environments.

Supply Voltage Compatibility: The SI8640AB-B-IS1R operates across 2.5V to 5.5V, which encompasses the original device's 2.7V to 5.5V range. Applications operating at 2.5V will require verification of the original design's actual operating point.

Compliance and Certification: Both devices carry identical ECCN (EAR99) and HTSUS (8542.39.0001) classifications, maintaining regulatory compliance for export and tariff purposes.

Frequently Asked Questions (FAQ)

Q: Can the SI8640AB-B-IS1R be used as a direct replacement for the SI8440AB-C-IS1R?

A: Yes. Both devices share identical isolation voltage, channel count, channel configuration, data rate, package format, and operating temperature range. The SI8640AB-B-IS1R is functionally equivalent and pin-compatible, with enhanced performance in CMTI and rise/fall time specifications.

Q: What is the difference in Common Mode Transient Immunity between these parts?

A: The SI8440AB-C-IS1R specifies 25kV/µs (Typ) CMTI, while the SI8640AB-B-IS1R specifies 35kV/µs. The higher CMTI rating of the substitute provides improved immunity to rapid voltage transients on the isolated side, reducing the risk of false signal transitions in noisy environments.

Q: Are there supply voltage considerations when substituting?

A: The SI8440AB-C-IS1R operates from 2.7V to 5.5V, while the SI8640AB-B-IS1R operates from 2.5V to 5.5V. If the original design operates at 2.5V, the substitute is compatible. If the original design operates below 2.5V, the substitute cannot be used without circuit modification.

Q: Is the 16-SOIC package identical between both parts?

A: Yes. Both devices use the 16-SOIC (0.154", 3.90mm Width) package. PCB footprints, land patterns, and mounting procedures are identical. No layout modifications are required.

Q: Why is the SI8440AB-C-IS1R marked "Not For New Designs"?

A: This designation indicates the part is in end-of-life phase and the manufacturer recommends against its use in new product development. The SI8640AB-B-IS1R, with Active status, is the recommended path forward for new designs and ongoing production.

Q: Are there any performance trade-offs when using the SI8640AB-B-IS1R?

A: No trade-offs exist. The SI8640AB-B-IS1R provides equivalent or superior performance across all measured parameters. Rise/fall times are faster (2.5ns versus 3.8ns/2.8ns), and CMTI is higher (35kV/µs versus 25kV/µs), representing performance improvements rather than compromises.

Q: What is the inventory status of the substitute part?

A: The SI8640AB-B-IS1R has 862 pieces in stock as new original inventory, ensuring availability for immediate procurement and production requirements.