4N37 Optoisolator Equivalent & Substitute Parts

Part Overview

The 4N37 is an optoisolator transistor with base output manufactured by Everlight Electronics Co Ltd. This component provides 5000Vrms isolation in a single-channel configuration with transistor output and integrated base connection. The device is rated for DC input and operates across an extended temperature range of -55°C to 110°C. The 4N37 is classified as Active product status and is ROHS3 compliant.

Substitute parts are necessary when the 4N37 is unavailable, when inventory constraints require alternative sourcing, or when application requirements align with the electrical and mechanical specifications of equivalent optoisolator devices in the same package category.

Substiute Parts

4N37

Everlight Electronics Co LtdIn Stock: 190864N37 Datasheet

Current PartRFQ

H11AG1M

onsemiIn Stock: 12402H11AG1M Datasheet

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H11D3M

onsemiIn Stock: 1623H11D3M Datasheet

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MCT5210M

onsemiIn Stock: 9733MCT5210M Datasheet

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MOC8204M

onsemiIn Stock: 12948MOC8204M Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute optoisolators for the 4N37 are selected based on the following criteria:

Package Compatibility: All substitute parts must use the 6-DIP (0.300", 7.62mm) through-hole package to ensure direct mechanical and electrical compatibility on printed circuit boards.

Output Configuration: All substitutes must feature transistor output with base connection to maintain functional equivalence in circuits designed for the 4N37.

Input Type: All substitutes must accept DC input to match the 4N37 input specification.

Isolation Voltage: Substitute parts operate at 4170Vrms isolation, which is lower than the 4N37 specification of 5000Vrms. This represents a functional trade-off and must be evaluated against application requirements.

Current Transfer Ratio: Substitute parts exhibit varying current transfer ratios ranging from 20% to 100% at different input currents. The 4N37 specifies 100% @ 10mA as the minimum threshold.

Output Voltage and Current Ratings: Substitute parts provide maximum output voltages ranging from 30V to 400V and output currents from 50mA to 150mA, compared to the 4N37 specification of 80V maximum output voltage.

Temperature Range: Substitute parts operate across -40°C to 100°C, which is narrower than the 4N37 range of -55°C to 110°C.

Regulatory Compliance: All substitute parts are ROHS3 compliant and carry EAR99 ECCN classification, matching the 4N37 compliance profile.

Parameter Comparison

Engineering Selection Recommendations

H11AG1M (onsemi): This substitute provides 4170Vrms isolation with 100% current transfer ratio at 1mA input. The device is suitable for applications where the lower isolation voltage is acceptable and where input current sensitivity is a design priority. Maximum output voltage is limited to 30V. Product status is Active with ROHS3 compliance.

H11D3M (onsemi): This substitute offers 4170Vrms isolation with 20% current transfer ratio at 10mA input and supports maximum output voltage of 200V. The higher output voltage rating makes this option suitable for applications requiring higher voltage switching. Product status is Active with ROHS3 compliance.

MCT5210M (onsemi): This substitute provides 4170Vrms isolation with 70% current transfer ratio at 3mA input and supports maximum output current of 150mA. The faster turn-off time of 400ns offers improved switching performance compared to the 4N37. Maximum output voltage is 30V. Product status is Active with ROHS3 compliance.

MOC8204M (onsemi): This substitute delivers 4170Vrms isolation with 20% current transfer ratio at 10mA input and the highest maximum output voltage rating of 400V among all substitutes. This option is suitable for high-voltage switching applications. Product status is Active with ROHS3 compliance.

All substitute parts maintain through-hole 6-DIP package compatibility, single-channel configuration, transistor-with-base output topology, and DC input type. All substitutes are ROHS3 compliant and carry EAR99 ECCN classification. The primary trade-off across all substitutes is the reduction in isolation voltage from 5000Vrms to 4170Vrms and the narrower operating temperature range of -40°C to 100°C compared to the 4N37 specification of -55°C to 110°C.

Frequently Asked Questions (FAQ)

Q: Can the 4N37 be directly replaced with any of these substitute parts on a circuit board?

A: All substitute parts use the identical 6-DIP (0.300", 7.62mm) through-hole package, enabling direct mechanical replacement on printed circuit boards. However, electrical compatibility must be verified against application requirements, particularly isolation voltage, output voltage rating, and current transfer ratio specifications.

Q: What is the primary difference between the 4N37 and the substitute parts?

A: The 4N37 provides 5000Vrms isolation voltage, while all substitute parts provide 4170Vrms isolation. Additionally, the 4N37 operates across -55°C to 110°C, whereas substitutes operate across -40°C to 100°C. All parts share identical package, output topology, and input type specifications.

Q: Which substitute part has the highest output voltage capability?

A: The MOC8204M supports a maximum output voltage of 400V, compared to 80V for the 4N37. The H11D3M supports 200V maximum output voltage. These higher ratings are suitable for applications requiring higher voltage switching levels.

Q: Which substitute part has the fastest switching speed?

A: The MCT5210M exhibits the fastest turn-off time at 400ns, compared to 9µs for the 4N37. The MCT5210M turn-on time is 10µs, matching the 4N37 specification.

Q: Are all substitute parts ROHS3 compliant?

A: Yes, all substitute parts listed are ROHS3 compliant and carry EAR99 ECCN classification, matching the regulatory compliance profile of the 4N37.

Q: What is the current transfer ratio difference between the 4N37 and substitutes?

A: The 4N37 specifies 100% current transfer ratio at 10mA input. The H11AG1M also provides 100% at 1mA input. The H11D3M and MOC8204M provide 20% at 10mA input. The MCT5210M provides 70% at 3mA input. Current transfer ratio selection depends on input current availability in the application circuit.

Q: Can the 4N37 be used in applications requiring operation below -40°C?

A: The 4N37 operates down to -55°C, while all substitute parts operate only to -40°C minimum. For applications requiring operation below -40°C, the 4N37 is the appropriate choice among these parts.

Q: Which substitute part is most similar to the 4N37 in terms of isolation voltage?

A: All substitute parts provide 4170Vrms isolation, which is approximately 17% lower than the 4N37 specification of 5000Vrms. No substitute part matches the 4N37 isolation voltage specification.