onsemi 4N37S Optoisolator Equivalent & Substitute Parts

Part Overview

The onsemi 4N37S is a single-channel optoisolator with transistor output and base connection, rated for 5300Vrms isolation voltage. This component is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support. The 4N37S operates across the temperature range of -55°C to 100°C and is packaged in 6-SMD surface mount configuration with gull wing leads.

Substiute Parts

4N37S

onsemiIn Stock: 32304N37S Datasheet

Current PartRFQ

4N37SM

onsemiIn Stock: 127594N37SM Datasheet

DirectRFQ

4N37S

onsemiIn Stock: 32304N37S Datasheet

DirectRFQ

4N37SM

onsemiIn Stock: 127594N37SM Datasheet

DirectRFQ

4N37-X009

Vishay Semiconductor Opto DivisionIn Stock: 22444N37-X009 Datasheet

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4N37S-TA

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

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4N37S-TA1

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

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4N37SMT&R

Isocom Components 2004 LTDIn Stock: 8614N37SMT&R Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the 4N37S optoisolator is determined by the following critical parameters:

• Isolation Voltage Rating: Minimum 5300Vrms or equivalent
• Output Configuration: Transistor with base connection required
• Number of Channels: Single channel only
• Package Type: 6-SMD surface mount with gull wing leads
• Current Transfer Ratio: Minimum 100% @ 10mA
• Output Voltage Rating: Maximum 30V
• Vce Saturation: Maximum 300mV
• Operating Temperature Range: Support for -55°C to 100°C minimum
• Input Type: DC input
• Mounting: Surface mount compatibility

Substitute parts are categorized as direct equivalents (same isolation voltage and specifications) or similar alternatives (different isolation voltage or manufacturer with compatible electrical characteristics).

Parameter Comparison

Engineering Selection Recommendations

Direct Equivalent - onsemi 4N37SM

The 4N37SM is an active product from the same manufacturer (onsemi) with identical package, pinout, and output configuration. It maintains the same 100% current transfer ratio at 10mA and identical switching times of 2µs. The primary difference is a reduced isolation voltage rating of 4170Vrms compared to the 4N37S at 5300Vrms, and a lower maximum forward current of 60mA versus 100mA. The 4N37SM is ROHS3 compliant and suitable for applications where the lower isolation voltage is acceptable. Operating temperature range is -40°C to 100°C, which covers most industrial applications but does not extend to -55°C.

Alternative - Vishay Semiconductor 4N37-X009

The 4N37-X009 provides 5000Vrms isolation voltage, closely matching the 4N37S specification. This part is ROHS3 compliant and active. It maintains the same 100% current transfer ratio and 30V maximum output voltage. Switching times are slower at 10µs compared to 2µs for the 4N37S. Operating temperature range is -55°C to 100°C, matching the original specification. Maximum forward current is 60mA.

Alternative - Lite-On 4N37S-TA1

The 4N37S-TA1 is an active product with the highest inventory availability (21,996 pcs). It features identical package, pinout, and output configuration with 100% current transfer ratio. However, isolation voltage is significantly lower at 1500Vrms. This part is ROHS3 compliant and operates across -55°C to 100°C. It is suitable only for applications where lower isolation voltage requirements are acceptable.

Alternative - Lite-On 4N37S-TA

The 4N37S-TA shares the same characteristics as the 4N37S-TA1 with 1500Vrms isolation voltage and ROHS3 compliance. It is packaged in Tape & Reel format and operates across -55°C to 100°C.

Alternative - Isocom 4N37SMT&R

The 4N37SMT&R is an active product with identical 2µs switching times and 300mV Vce saturation. However, the isolation voltage specification of 7.5Vpk is significantly lower than the 4N37S. This part is ROHS3 compliant and operates across -55°C to 100°C. It is suitable only for low-voltage isolation applications.

Frequently Asked Questions (FAQ)

Q: Can the 4N37SM directly replace the 4N37S in all applications?

A: The 4N37SM is a direct pin-compatible substitute with identical package and output configuration. However, the isolation voltage is reduced from 5300Vrms to 4170Vrms. Substitution is valid only if your application does not require the full 5300Vrms isolation rating. The -40°C to 100°C operating temperature range also does not extend to -55°C, which may be a limitation in extreme cold environments.

Q: What is the key difference between the 4N37S and the Vishay 4N37-X009?

A: Both parts provide similar isolation voltage ratings (5300Vrms vs. 5000Vrms) and identical current transfer ratios. The primary difference is switching speed: the 4N37S switches in 2µs while the 4N37-X009 requires 10µs. The 4N37-X009 is ROHS3 compliant and active, making it suitable for new designs requiring high isolation voltage with slightly slower response times.

Q: Why do the Lite-On 4N37S-TA and 4N37S-TA1 have much lower isolation voltage?

A: The Lite-On variants (1500Vrms) are designed for different application requirements than the original 4N37S (5300Vrms). These parts are suitable only for applications requiring lower isolation voltage. They share the same package, pinout, and output configuration but cannot be used as direct substitutes in high-voltage isolation circuits.

Q: Is the 4N37SMT&R from Isocom a suitable replacement?

A: The 4N37SMT&R maintains identical switching times and saturation voltage but has significantly lower isolation voltage (7.5Vpk). This part is suitable only for applications with minimal isolation voltage requirements and cannot serve as a general replacement for the 4N37S.

Q: What packaging options are available for substitutes?

A: All substitute parts maintain the 6-SMD surface mount package with gull wing leads, ensuring mechanical compatibility. The 4N37SM is supplied in Tube packaging, while the Lite-On variants (4N37S-TA and 4N37S-TA1) and Isocom 4N37SMT&R are supplied in Tape & Reel format. Packaging format does not affect electrical performance or pinout compatibility.

Q: Are all substitute parts RoHS compliant?

A: Yes, all active substitute parts listed (4N37SM, 4N37-X009, 4N37S-TA, 4N37S-TA1, and 4N37SMT&R) are ROHS3 compliant. The original 4N37S does not specify RoHS status due to its obsolete classification.

Q: Which substitute offers the best inventory availability?

A: The Lite-On 4N37S-TA1 has the highest inventory at 21,996 pcs. The onsemi 4N37SM has 12,680 pcs available. However, inventory availability should be secondary to electrical compatibility with your specific application requirements.