H11A3SD Optoisolator Equivalent & Substitute Parts

Part Overview

The H11A3SD is a single-channel optoisolator transistor with base output manufactured by onsemi, rated for 5300Vrms isolation voltage in a 6-SMD surface mount package. This component is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and procurement planning. The H11A3SD serves applications requiring galvanic isolation with transistor output capability and integrated base connection for enhanced switching control.

Substiute Parts

H11A3SD

onsemiIn Stock: 3208H11A3SD Datasheet

Current PartRFQ

4N25SR2M

onsemiIn Stock: 943354N25SR2M Datasheet

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H11A3SM

onsemiIn Stock: 12345H11A3SM Datasheet

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H11A3SMT&R

Isocom Components 2004 LTDIn Stock: 1012H11A3SMT&R Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the H11A3SD is determined by the following critical parameters:

• Single-channel configuration: All substitute parts must provide exactly one isolated channel
• Transistor output with base connection: Output stage must include base terminal for direct drive capability
• 6-SMD surface mount package: Physical and electrical compatibility requires identical package footprint
• DC input type: Input stage must accept DC signal levels
• Isolation voltage rating: Substitute must meet or exceed 5300Vrms isolation specification
• Output voltage capability: Maximum output voltage must be 30V or greater
• Current transfer ratio: Minimum 20% @ 10mA transfer ratio required
• Switching speed: Turn-on and turn-off times of 2µs or faster acceptable
• Temperature range: Operating range must encompass -55°C to 100°C or be compatible with application requirements

Three substitute parts meet these criteria with varying isolation voltage ratings and product status classifications.

Parameter Comparison

Engineering Selection Recommendations

4N25SR2M (onsemi): Active product status provides ongoing manufacturer support and availability. Isolation voltage of 4170Vrms is lower than the H11A3SD specification; this substitute is suitable only for applications where reduced isolation voltage is acceptable. Forward current maximum of 60 mA versus 100 mA in the original part represents a design constraint. RoHS3 compliance certification is provided. Temperature range of -40°C to 100°C excludes low-temperature operation below -40°C.

H11A3SM (onsemi): Obsolete product status mirrors the main part, offering no long-term procurement advantage. Isolation voltage of 7500Vpk exceeds the H11A3SD requirement, providing margin for high-voltage applications. Vce saturation of 400mV matches the original specification. Forward current maximum of 60 mA represents a reduction from 100 mA. Temperature range of -40°C to 100°C excludes extended low-temperature operation.

H11A3SMT&R (Isocom Components 2004 LTD): Active product status ensures continued availability and manufacturer support. Isolation voltage specification of 7.5Vpk is significantly lower than required and indicates a data entry anomaly; this part is not suitable for the H11A3SD application. RoHS3 compliance certification is provided. Operating temperature range of -55°C to 100°C matches the original part specification. Output current capability of 50mA is lower than the original 100 mA specification.

Frequently Asked Questions (FAQ)

Q: Can the 4N25SR2M replace the H11A3SD in all applications?

A: The 4N25SR2M is suitable only for applications where isolation voltage of 4170Vrms meets system requirements. If the design requires 5300Vrms isolation, this substitute is not appropriate. Additionally, the reduced forward current maximum of 60 mA versus 100 mA must be verified against circuit current demands.

Q: What is the primary advantage of H11A3SM over the H11A3SD?

A: The H11A3SM provides higher isolation voltage rating of 7500Vpk, offering additional safety margin in high-voltage isolation applications. However, both parts share obsolete status, limiting long-term procurement viability.

Q: Is H11A3SMT&R a direct replacement?

A: The H11A3SMT&R cannot serve as a direct replacement due to isolation voltage specification of 7.5Vpk, which is substantially below the H11A3SD requirement of 5300Vrms. This represents a critical incompatibility.

Q: Which substitute offers the best long-term availability?

A: The 4N25SR2M and H11A3SMT&R both carry active product status, ensuring ongoing manufacturer support and procurement availability. The 4N25SR2M is manufactured by onsemi, the original H11A3SD manufacturer, providing design continuity.

Q: Are all substitutes available in the same package?

A: All substitute parts are available in 6-SMD, Gull Wing surface mount package, ensuring physical compatibility with existing PCB layouts.

Q: What compliance certifications apply to these substitutes?

A: The 4N25SR2M and H11A3SMT&R carry RoHS3 compliance certification. All parts maintain MSL 1 (Unlimited) moisture sensitivity rating and REACH Unaffected status.