4N37S Optoisolator Equivalent & Substitute Parts

Part Overview

The 4N37S is an optoisolator transistor with base output manufactured by Lite-On Inc., designed for 1500Vrms isolation applications. This component features a single channel configuration with transistor output and base connection in a 6-SMD surface mount package. The part is currently active in production with full RoHS3 compliance and unlimited moisture sensitivity rating.

Substitute parts are identified to address inventory availability, extended isolation voltage requirements, or alternative packaging formats while maintaining functional compatibility within the 4N37 base product family.

Substiute Parts

4N37S

Lite-On Inc.In Stock: 32634N37S Datasheet

Current PartRFQ

4N37SM

onsemiIn Stock: 127594N37SM Datasheet

MFR RecommendedRFQ

4N37SR2M

onsemiIn Stock: 18614N37SR2M Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the 4N37S are identified from the 4N37 base product family. Substitution eligibility is determined by the following critical parameters:

• Single channel configuration maintained across all substitutes
• Transistor with base output topology preserved
• 6-SMD, Gull Wing package format consistent
• Maximum output voltage of 30V maintained
• Vce saturation maximum of 300mV maintained
• Current transfer ratio minimum of 100% @ 10mA maintained
• Surface mount mounting type preserved
• RoHS3 compliance and MSL 1 rating maintained

The substitute parts 4N37SM and 4N37SR2M differ from the main part in isolation voltage rating (4170Vrms versus 1500Vrms), packaging format (Tube or Tape & Reel), and operating temperature range (-40°C ~ 100°C versus -55°C ~ 100°C). These differences represent enhanced specifications or alternative delivery formats within the same functional family.

Parameter Comparison

Engineering Selection Recommendations

Selection between 4N37S and its substitutes is based on application requirements and product availability:

The 4N37S remains the primary choice for applications requiring the specified 1500Vrms isolation voltage with operating temperatures down to -55°C. This part maintains active production status with established supply channels.

The 4N37SM (onsemi, Tube packaging) provides enhanced isolation voltage of 4170Vrms with identical electrical characteristics and package format. This substitute is suitable for applications requiring higher isolation margins or when onsemi supply chain preference is established. Operating temperature range is limited to -40°C ~ 100°C.

The 4N37SR2M (onsemi, Tape & Reel packaging) offers the same enhanced isolation voltage as 4N37SM with Tape & Reel delivery format. This packaging option is appropriate for high-volume automated assembly processes. Operating temperature range is -40°C ~ 100°C.

All three parts maintain RoHS3 compliance, MSL 1 rating, and identical functional output specifications. Selection should account for isolation voltage requirements, operating temperature range, packaging format compatibility with assembly equipment, and supplier availability.

Frequently Asked Questions (FAQ)

Q: Can 4N37SM or 4N37SR2M be used as direct replacements for 4N37S?

A: Yes, within the constraints of operating temperature range and isolation voltage requirements. The 4N37SM and 4N37SR2M provide higher isolation voltage (4170Vrms) and are electrically compatible. However, the operating temperature minimum is -40°C instead of -55°C. If your application requires operation below -40°C, the 4N37S is required.

Q: What is the difference between 4N37SM and 4N37SR2M?

A: Both parts are manufactured by onsemi with identical electrical specifications and isolation voltage. The primary difference is packaging format: 4N37SM is supplied in Tube format, while 4N37SR2M is supplied in Tape & Reel (TR) format. Tape & Reel packaging is optimized for automated pick-and-place assembly, while Tube packaging is suitable for manual or semi-automated handling.

Q: Are there any compatibility concerns with the 6-SMD, Gull Wing package across all three parts?

A: No. All three parts use the same 6-SMD, Gull Wing package format with identical pinout and footprint. PCB layout and assembly processes are fully compatible across 4N37S, 4N37SM, and 4N37SR2M.

Q: What does the higher isolation voltage of 4N37SM and 4N37SR2M mean for my application?

A: The 4170Vrms isolation rating of 4N37SM and 4N37SR2M provides greater electrical separation between input and output circuits compared to the 1500Vrms rating of 4N37S. This higher rating offers increased safety margin in high-voltage isolation applications and may be required by certain safety standards or application specifications.

Q: Which part should I select for high-volume production?

A: For high-volume automated assembly, 4N37SR2M (Tape & Reel format) is the standard choice. For lower volumes or manual assembly processes, 4N37SM (Tube format) or 4N37S (Tube format) may be more practical. Consult your assembly partner regarding packaging format compatibility with your production equipment.

Q: Are all three parts RoHS3 compliant?

A: Yes. The 4N37S, 4N37SM, and 4N37SR2M are all RoHS3 compliant with MSL 1 (Unlimited) moisture sensitivity rating, meeting current environmental and reliability standards.