SI8420AD-A-ISR Digital Isolator Equivalent & Substitute Parts

Part Overview

The SI8420AD-A-ISR is a general purpose digital isolator manufactured by Skyworks Solutions Inc., featuring 5000Vrms isolation voltage and 2-channel unidirectional configuration in a 16-SOIC package. This component is classified as obsolete, making identification of suitable substitute parts essential for ongoing system support and new design implementations. The part utilizes capacitive coupling technology to provide galvanic isolation between logic circuits operating at different voltage domains.

Substiute Parts

SI8420AD-A-ISR

Skyworks Solutions Inc.In Stock: 803SI8420AD-A-ISR Datasheet

Current PartRFQ

ISO7820LLDWR

Texas InstrumentsIn Stock: 4270ISO7820LLDWR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the SI8420AD-A-ISR is determined by the following critical parameters:

• Isolation Voltage: Substitute must meet or exceed 5000Vrms
• Channel Count & Configuration: Must provide 2 channels with unidirectional input capability (minimum 2 inputs on Side 1)
• Package Type: Must be 16-SOIC (0.295", 7.50mm Width) for PCB layout compatibility
• Technology: Capacitive coupling technology ensures functional equivalence
• Supply Voltage Compatibility: Operating range must encompass or overlap with 2.7V – 5.5V
• Operating Temperature: Must support -40°C to 125°C range

The ISO7820LLDWR from Texas Instruments satisfies all substitution criteria, offering enhanced performance specifications while maintaining full pin and package compatibility.

Parameter Comparison

Engineering Selection Recommendations

The ISO7820LLDWR is a direct functional substitute for the SI8420AD-A-ISR based on the following engineering criteria:

Package and Pinout Compatibility: Both components utilize the 16-SOIC (0.295", 7.50mm Width) package with identical pin assignments for 2-channel unidirectional digital isolation, enabling direct PCB layout compatibility without redesign.

Electrical Parameter Compliance: The ISO7820LLDWR meets all minimum electrical requirements of the SI8420AD-A-ISR while providing superior performance margins. The 5700Vrms isolation voltage exceeds the 5000Vrms requirement, and the 100kV/µs CMTI specification significantly exceeds the 20kV/µs minimum, providing enhanced noise immunity in high-speed switching environments.

Product Status and Availability: The ISO7820LLDWR is in active production status with documented inventory availability (4170 pcs), whereas the SI8420AD-A-ISR is obsolete. This substitution ensures long-term supply chain continuity and access to current manufacturing processes.

Regulatory Compliance: The ISO7820LLDWR carries ROHS3 compliance certification and REACH unaffected status, meeting current environmental and regulatory standards. The SI8420AD-A-ISR compliance status is not specified.

Performance Enhancement: The substitute part delivers improved propagation delay (25ns vs. 35ns), reduced pulse width distortion (4.5ns vs. 25ns), and extended operating temperature range (-55°C to 125°C vs. -40°C to 125°C), providing design margin for demanding applications.

Frequently Asked Questions (FAQ)

Q: Can the ISO7820LLDWR be used as a direct replacement for the SI8420AD-A-ISR without PCB modifications?

A: Yes. Both components share identical 16-SOIC package dimensions and pinout configuration. The ISO7820LLDWR can be substituted without PCB layout changes or signal routing modifications.

Q: What are the key differences between these two isolators?

A: The ISO7820LLDWR provides enhanced specifications across multiple parameters: 5700Vrms isolation (vs. 5000Vrms), 100Mbps data rate (vs. 1Mbps), 100kV/µs CMTI (vs. 20kV/µs), and improved propagation delay and pulse width distortion. Both maintain identical 2-channel unidirectional configuration and capacitive coupling technology.

Q: Is the ISO7820LLDWR suitable for applications originally designed for the SI8420AD-A-ISR?

A: Yes. The ISO7820LLDWR exceeds all electrical and thermal requirements of the original design. Applications operating within the SI8420AD-A-ISR specifications will function identically with the substitute part, with improved performance margins and reliability.

Q: What is the supply voltage compatibility between these parts?

A: The SI8420AD-A-ISR operates from 2.7V to 5.5V, while the ISO7820LLDWR operates from 2.25V to 5.5V. The substitute part extends the lower supply voltage range, providing greater design flexibility for low-voltage applications.

Q: Are there any temperature range considerations for substitution?

A: The ISO7820LLDWR supports -55°C to 125°C, extending the lower operating temperature limit by 15°C compared to the SI8420AD-A-ISR (-40°C to 125°C). This provides additional margin for applications in cold environments.

Q: What packaging options are available for the ISO7820LLDWR?

A: The ISO7820LLDWR is supplied in Cut Tape (CT) and Digi-Reel packaging formats, as well as Tape & Reel (TR) configuration. Verify packaging format availability with your supplier to match your procurement and assembly requirements.

Q: Does the substitute part meet current regulatory standards?

A: Yes. The ISO7820LLDWR is ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements. The original SI8420AD-A-ISR compliance status is not documented.