4N29SD Optoisolator Equivalent & Substitute Parts

Part Overview

The 4N29SD is an optoisolator with Darlington output and base connection, manufactured by onsemi. This component provides 5300Vrms isolation voltage in a 6-SMD surface mount package. The 4N29SD is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain functional compatibility across isolation voltage, output characteristics, and thermal operating range.

Substiute Parts

4N29SD

onsemiIn Stock: 27674N29SD Datasheet

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4N29SR2M

onsemiIn Stock: 160474N29SR2M Datasheet

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4N29SM

onsemiIn Stock: 51484N29SM Datasheet

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4N29SMT&R

Isocom Components 2004 LTDIn Stock: 19054N29SMT&R Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the 4N29SD is determined by the following critical parameters:

• Isolation Voltage: The 4N29SD provides 5300Vrms isolation. Substitute parts must maintain isolation voltage at or above this specification to ensure electrical safety and regulatory compliance.
• Output Configuration: Darlington with base output is required for functional compatibility with existing circuit designs.
• Number of Channels: Single channel configuration must be preserved.
• Output Voltage and Current Ratings: Maximum output voltage of 30V and channel current of 150mA define the load-driving capability.
• Switching Characteristics: Turn-on and turn-off times of 5µs and 40µs (max) establish timing requirements.
• Package Type: 6-SMD, Gull Wing surface mount package ensures mechanical and electrical compatibility with PCB layouts.
• Operating Temperature Range: The 4N29SD operates from -55°C to 100°C; substitute parts must cover this range or a subset thereof.

The substitute parts identified (4N29SR2M, 4N29SM, 4N29SMT&R) share the same base product number (4N29) and maintain core functional parameters. However, isolation voltage differs across variants, requiring careful selection based on application requirements.

Parameter Comparison

Engineering Selection Recommendations

4N29SR2M (onsemi, Active Status)

The 4N29SR2M is an active product from onsemi with ROHS3 compliance. It maintains the same output configuration, voltage/current ratings, and switching characteristics as the 4N29SD. The isolation voltage is reduced to 4170Vrms, and the operating temperature range is narrowed to -40°C ~ 100°C. This part is suitable for applications where the lower isolation voltage is acceptable and the minimum operating temperature does not fall below -40°C. Tape & Reel packaging supports high-volume production.

4N29SM (onsemi, Active Status)

The 4N29SM is functionally equivalent to the 4N29SR2M with identical electrical specifications and ROHS3 compliance. The primary difference is packaging format (Tube instead of Tape & Reel), making it suitable for lower-volume applications or manual assembly processes. The same isolation voltage and temperature range limitations apply.

4N29SMT&R (Isocom Components 2004 LTD, Active Status)

The 4N29SMT&R is manufactured by Isocom Components 2004 LTD and maintains Darlington output configuration with ROHS3 compliance. Detailed electrical parameters are not provided in the specification data. This part is suitable only when complete parameter verification against application requirements can be performed independently.

Frequently Asked Questions (FAQ)

Q: Can the 4N29SR2M or 4N29SM directly replace the 4N29SD?

A: Direct replacement depends on application isolation voltage requirements. The 4N29SR2M and 4N29SM provide 4170Vrms isolation compared to the 4N29SD's 5300Vrms. If the application requires 5300Vrms isolation, these parts are not suitable. If the application operates at or below 4170Vrms isolation, these parts are functionally compatible. The operating temperature range is also narrower (-40°C ~ 100°C versus -55°C ~ 100°C).

Q: What is the difference between 4N29SR2M and 4N29SM?

A: Both parts are manufactured by onsemi with identical electrical specifications. The difference is packaging format: 4N29SR2M is supplied in Tape & Reel (TR) format for automated assembly, while 4N29SM is supplied in Tube format for manual or semi-automated assembly. Selection depends on production volume and assembly equipment.

Q: Why is the 4N29SMT&R listed as a substitute if specifications are incomplete?

A: The 4N29SMT&R is listed based on the provided substitute list and shares the same base product number (4N29). However, incomplete electrical parameter data limits direct compatibility assessment. This part should be selected only after independent verification of isolation voltage, output ratings, and switching characteristics against application requirements.

Q: Does the 4N29SD's obsolete status affect availability of substitutes?

A: Yes. The 4N29SD is obsolete, but active substitute parts (4N29SR2M, 4N29SM, 4N29SMT&R) are available. Inventory levels vary by part and packaging format. The 4N29SR2M has the highest inventory (16,000 pcs), followed by 4N29SM (5,100 pcs) and 4N29SMT&R (1,818 pcs).

Q: Are all substitute parts RoHS compliant?

A: The 4N29SR2M, 4N29SM, and 4N29SMT&R are all ROHS3 compliant. The original 4N29SD RoHS status is not specified in the provided data.

Q: What are the REACH and ECCN classifications for these parts?

A: All listed parts (4N29SD, 4N29SR2M, 4N29SM, 4N29SMT&R) are REACH Unaffected and classified as EAR99 for export control purposes.