4N37S-TA Optoisolator Equivalent & Substitute Parts

Part Overview

The 4N37S-TA is an optoisolator transistor with base output manufactured by Lite-On Inc., designed for 1500Vrms isolation applications. This single-channel device features a 6-SMD surface mount package and is classified as Active product status. Alternative part numbers become necessary when addressing specific inventory constraints, packaging requirements, or enhanced isolation voltage specifications while maintaining core functional compatibility within the 4N3X series.

Substiute Parts

4N37S-TA

Lite-On Inc.In Stock: 34104N37S-TA Datasheet

Current PartRFQ

4N37S-TA1

Lite-On Inc.In Stock: 220534N37S-TA1 Datasheet

Parametric EquivalentRFQ

4N37SM

onsemiIn Stock: 127594N37SM Datasheet

MFR RecommendedRFQ

4N37SR2M

onsemiIn Stock: 18614N37SR2M Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 4N37S-TA is determined by the following critical parameters: isolation voltage rating, number of channels, output type (transistor with base), current transfer ratio minimum specification, maximum output voltage, maximum output current per channel, and package configuration (6-SMD, Gull Wing surface mount).

The substitute parts are grouped into two categories:

Parametric Equivalent (4N37S-TA1): Maintains identical electrical specifications and isolation voltage (1500Vrms), differing only in packaging format (Tape & Reel) and inventory availability.

Enhanced Isolation Alternatives (4N37SM, 4N37SR2M): Manufactured by onsemi, these parts provide increased isolation voltage (4170Vrms) while preserving all other critical parameters including output type, current transfer ratio, maximum output voltage, and package configuration. These represent functional upgrades suitable for applications requiring higher isolation margins.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (4N37S-TA1): Select this part when inventory or packaging format constraints require an alternative to the 4N37S-TA. Both parts maintain identical electrical performance and isolation voltage specifications. The 4N37S-TA1 is suitable for applications with existing 1500Vrms isolation requirements and offers higher inventory availability.

For Enhanced Isolation Applications (4N37SM, 4N37SR2M): These onsemi alternatives provide 4170Vrms isolation voltage, representing a 2.78x increase over the base specification. Select these parts when circuit design requires higher isolation margins or when operating in environments with elevated voltage stress conditions. Both maintain all critical output characteristics and are ROHS3 compliant. The 4N37SR2M offers Tape & Reel packaging, while 4N37SM is supplied in Tube format.

All substitute parts maintain Active product status and comply with ROHS3 and REACH requirements, ensuring long-term availability and regulatory compliance for production applications.

Frequently Asked Questions (FAQ)

Q: Can 4N37S-TA1 be used as a direct drop-in replacement for 4N37S-TA?

A: Yes. The 4N37S-TA1 maintains identical electrical specifications, isolation voltage (1500Vrms), output type, current transfer ratio, and package configuration (6-SMD, Gull Wing). The only difference is packaging format (Tape & Reel for both), making it a true parametric equivalent.

Q: What is the primary difference between 4N37S-TA and the onsemi alternatives (4N37SM, 4N37SR2M)?

A: The onsemi parts provide 4170Vrms isolation voltage compared to 1500Vrms in the Lite-On part. All other critical parameters—output type, current transfer ratio, maximum output voltage (30V), and package configuration—remain identical. This represents an enhanced isolation specification rather than a functional change.

Q: Are 4N37SM and 4N37SR2M electrically interchangeable?

A: Yes, electrically they are identical. Both feature 4170Vrms isolation, 100% minimum current transfer ratio, 30V maximum output voltage, and 300mV maximum Vce saturation. The difference is packaging format: 4N37SM is supplied in Tube, while 4N37SR2M is supplied in Tape & Reel.

Q: What is the operating temperature difference between Lite-On and onsemi parts?

A: Lite-On 4N37S-TA and 4N37S-TA1 operate from -55°C to 100°C. The onsemi alternatives (4N37SM, 4N37SR2M) operate from -40°C to 100°C. For applications requiring -55°C operation, the Lite-On parts are required.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All parts listed—4N37S-TA, 4N37S-TA1, 4N37SM, and 4N37SR2M—are ROHS3 compliant with Moisture Sensitivity Level 1 (Unlimited), suitable for production and long-term storage without special handling.

Q: Which part should be selected for new designs?

A: For new designs, evaluate isolation voltage requirements. If 1500Vrms is sufficient, either Lite-On part (4N37S-TA or 4N37S-TA1) is appropriate. If higher isolation margins are desired, the onsemi alternatives (4N37SM or 4N37SR2M) provide 4170Vrms. Verify operating temperature range requirements: Lite-On parts support -55°C minimum, while onsemi parts support -40°C minimum.