4N28S Optoisolator Equivalent & Substitute Parts

Part Overview

The 4N28S is a single-channel optoisolator with transistor output and base connection, rated for 5300Vrms isolation voltage. Manufactured by onsemi, this component is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support. The 4N28S operates with a 1 Channel configuration, 6-SMD gull wing package, and supports DC input with transistor-based output topology.

Substiute Parts

4N28S

onsemiIn Stock: 61384N28S Datasheet

Current PartRFQ

4N28SM

onsemiIn Stock: 28004N28SM Datasheet

DirectRFQ

4N28SM

onsemiIn Stock: 28004N28SM Datasheet

DirectRFQ

4N28-X009T

Vishay Semiconductor Opto DivisionIn Stock: 126414N28-X009T Datasheet

SimilarRFQ

4N28S

onsemiIn Stock: 61384N28S Datasheet

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4N28S-TA

Lite-On Inc.In Stock: 10624N28S-TA Datasheet

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4N28S-TA1

Lite-On Inc.In Stock: 9114N28S-TA1 Datasheet

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4N28SMT&R

Isocom Components 2004 LTDIn Stock: 11214N28SMT&R Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 4N28S is determined by the following critical parameters:

• Isolation Voltage Rating: Minimum 5000Vrms to maintain equivalent isolation performance
• Output Configuration: Transistor with Base output topology required
• Number of Channels: Single channel (1 Channel) configuration
• Package Type: 6-SMD, Gull Wing surface mount package
• Input Type: DC input compatibility
• Current Transfer Ratio: Minimum 10% @ 10mA
• Vce Saturation: Maximum 500mV
• Operating Temperature Range: Support for -55°C minimum and 100°C maximum

Based on these parameters, the following parts qualify as direct or similar substitutes:

Direct Manufacturer Substitute:

• 4N28SM (onsemi) — Active product status, same base platform

Similar Substitutes (Equivalent Isolation & Output Characteristics):

• 4N28-X009T (Vishay Semiconductor Opto Division) — 5000Vrms isolation, active status
• 4N28S (onsemi) — Original part reference, obsolete status

Limited Compatibility Substitutes (Reduced Isolation Voltage):

• 4N28S-TA (Lite-On Inc.) — 500Vrms isolation, not suitable for high-voltage isolation applications
• 4N28S-TA1 (Lite-On Inc.) — 500Vrms isolation, not suitable for high-voltage isolation applications
• 4N28SMT&R (Isocom Components 2004 LTD) — 7.5Vpk isolation, not suitable for high-voltage isolation applications

Parameter Comparison

Engineering Selection Recommendations

For High-Voltage Isolation Applications (≥5000Vrms Required):

Select 4N28-X009T (Vishay Semiconductor Opto Division). This part maintains 5000Vrms isolation voltage, meets the 6-SMD gull wing package requirement, and holds active product status with ROHS3 compliance. Operating temperature range of -55°C to 100°C matches the original specification.

For Standard Isolation Applications (4170Vrms Acceptable):

Select 4N28SM (onsemi). This direct manufacturer substitute provides active product status, ROHS3 compliance, and identical electrical characteristics to the 4N28S except for reduced isolation voltage (4170Vrms vs. 5300Vrms) and lower maximum forward current (60 mA vs. 100 mA). Operating temperature minimum is -40°C, which may limit use in extreme cold environments.

Not Recommended for Direct Substitution:

Parts 4N28S-TA, 4N28S-TA1, and 4N28SMT&R exhibit isolation voltage ratings significantly below the 4N28S specification (500Vrms and 7.5Vpk respectively) and are unsuitable for applications requiring high-voltage isolation performance.

Frequently Asked Questions (FAQ)

Q: Can 4N28SM replace 4N28S in all applications?

A: 4N28SM is suitable for applications where 4170Vrms isolation voltage is acceptable. The primary differences are reduced isolation voltage (4170Vrms vs. 5300Vrms), lower maximum forward current (60 mA vs. 100 mA), and narrower operating temperature range (-40°C minimum vs. -55°C). Applications requiring the full 5300Vrms isolation specification should use 4N28-X009T instead.

Q: What is the key difference between 4N28-X009T and 4N28SM?

A: 4N28-X009T (Vishay) maintains 5000Vrms isolation voltage and supports higher maximum output voltage (70V vs. 30V) and output current (50mA vs. unspecified). 4N28SM (onsemi) provides 4170Vrms isolation. Both share identical 6-SMD gull wing packaging and DC input with transistor base output topology.

Q: Why are 4N28S-TA and 4N28S-TA1 not suitable substitutes?

A: These Lite-On parts feature 500Vrms isolation voltage, which is approximately 10 times lower than the 4N28S specification. They are designed for low-voltage isolation applications and do not meet high-voltage isolation requirements.

Q: Does packaging differ between substitute options?

A: All substitute parts use 6-SMD gull wing surface mount packaging, maintaining mechanical and electrical compatibility with PCB layouts designed for the 4N28S. Packaging variations exist only in tape & reel versus tube configurations, which do not affect component functionality.

Q: What compliance certifications should I verify for new designs?

A: 4N28SM and 4N28-X009T both carry ROHS3 compliance certification. Both parts maintain MSL 1 (Unlimited) moisture sensitivity rating and EAR99 export classification, matching the original 4N28S specifications.