4N27S-TA Optoisolator Equivalent & Substitute Parts

Part Overview

The 4N27S-TA is an optoisolator transistor with base output manufactured by Lite-On Inc., designed for 1500Vrms isolation applications in 6-SMD surface mount packaging. This component provides galvanic isolation between input and output circuits with a single channel configuration and transistor output with accessible base terminal. The part is currently active in production with ROHS3 compliance and unlimited moisture sensitivity rating (MSL 1).

Substitute parts are identified when equivalent electrical and mechanical parameters align with the main part's functional requirements, enabling direct replacement in compatible circuit designs.

Substiute Parts

4N27S-TA

Lite-On Inc.In Stock: 11994N27S-TA Datasheet

Current PartRFQ

4N27SM

onsemiIn Stock: 164844N27SM Datasheet

MFR RecommendedRFQ

4N27SR2M

Fairchild SemiconductorIn Stock: 23084N27SR2M Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 4N27S-TA are identified based on the following critical parameters that determine functional compatibility:

Core Compatibility Criteria:

• Single channel configuration (Number of Channels = 1)
• Transistor output with base terminal (Output Type)
• Maximum output voltage of 30V or greater
• Vce saturation maximum of 500mV or less
• 6-SMD, Gull Wing surface mount package
• Current Transfer Ratio minimum of 10% @ 10mA or greater
• Input Type: DC
• ROHS3 compliance and active product status

Isolation Voltage Consideration: The 4N27S-TA specifies 1500Vrms isolation. Substitute parts with higher isolation voltage ratings (4170Vrms) maintain backward compatibility and provide enhanced isolation margin for the same application circuit. Lower isolation ratings would not qualify as substitutes.

Temperature Range: The main part operates from -55°C to 100°C. Substitute parts with narrower operating ranges (-40°C to 100°C) are acceptable for applications not requiring the extended low-temperature performance of the original part.

Parameter Comparison

Engineering Selection Recommendations

4N27SM (onsemi): This part qualifies as a direct substitute based on matching electrical parameters and package configuration. The higher isolation voltage rating (4170Vrms versus 1500Vrms) provides additional safety margin without affecting circuit operation. Both parts maintain ROHS3 compliance and active production status. The operating temperature range is narrower (-40°C to 100°C), which is acceptable for applications not requiring extended low-temperature operation below -40°C.

4N27SR2M (Fairchild Semiconductor): This part meets all electrical and mechanical compatibility requirements with identical channel count, output type, saturation voltage, and package specification. The isolation voltage rating of 4170Vrms exceeds the original specification. RoHS compliance status is not specified in the provided data. Active product status is confirmed. The operating temperature range matches the onsemi substitute at -40°C to 100°C.

Both substitute parts are suitable for applications where the 4N27S-TA is specified, provided the operating temperature range requirement does not extend below -40°C.

Frequently Asked Questions (FAQ)

Q: Can the 4N27SM or 4N27SR2M be used as direct replacements for the 4N27S-TA in existing designs?

A: Yes, both parts meet the core electrical and mechanical requirements for direct substitution. The package type (6-SMD, Gull Wing), pin configuration, output type (transistor with base), and critical electrical parameters (isolation voltage, saturation voltage, current transfer ratio) are compatible. PCB layout and footprint remain unchanged.

Q: Why do the substitute parts have higher isolation voltage ratings (4170Vrms) than the original (1500Vrms)?

A: Higher isolation voltage ratings provide enhanced safety margin and do not negatively impact circuit performance. The substitute parts will function identically in applications designed for 1500Vrms isolation. The higher rating simply indicates greater dielectric strength.

Q: What is the significance of the operating temperature range difference (-55°C to 100°C versus -40°C to 100°C)?

A: The 4N27S-TA supports operation at temperatures as low as -55°C, while the substitute parts are rated only to -40°C. For applications requiring operation below -40°C, the 4N27S-TA must be retained. For applications with minimum operating temperatures of -40°C or higher, the substitutes are fully compatible.

Q: Are there any differences in switching speed between these parts?

A: The 4N27S-TA specifies rise and fall times of 3µs each. The substitute parts specify turn-on and turn-off times of 2µs each, indicating slightly faster switching response. This difference is not detrimental to circuit operation and may provide improved performance in timing-sensitive applications.

Q: Do all three parts have the same moisture sensitivity level?

A: The 4N27S-TA and 4N27SM both specify MSL 1 (Unlimited). The 4N27SR2M moisture sensitivity level is not provided in the available data. MSL 1 indicates no moisture sensitivity restrictions during storage or handling.

Q: What packaging formats are available for these parts?

A: The 4N27S-TA is supplied in standard packaging (not specified). The 4N27SM is available in Tube packaging. The 4N27SR2M is available in Bulk packaging. All three parts use identical 6-SMD, Gull Wing surface mount package configuration for the component itself.