All Alternatives

Alternatives to onsemi 4N37

onsemi 4N37 and its qualified second sources, compared on form/fit/function, stock, lifecycle and price — the same checks Parter runs inside a BOM.

Equivalent and substitute parts for onsemi 4N37

4N37 compared against its qualified second sources
4N37onsemi4N37Monsemi4N37Vishay Semiconductor Opto Division+3more
FFF CompatibilityStandard 6-DIP footprint and identical pin layout (Pin 1 Anode, Pin 2 Cathode, Pin 3 NC, Pin 4 Emitter, Pin 5 Collector, Pin 6 Base).Identical physical dimensions and mounting style (through-hole DIP-6), though housed in a white package body instead of the obsolete black body.Isolation voltage (4170Vrms) and maximum DC forward current (60mA) are lower than the original obsolete part's ratings (5300Vrms and 100mA respectively).Standard 6-DIP footprint and identical pinout (Pin 1 Anode, Pin 2 Cathode, Pin 3 NC, Pin 4 Emitter, Pin 5 Collector, Pin 6 Base).Standard DIP-6 dimensions and through-hole mounting.Isolation voltage is slightly lower (5000Vrms vs 5300Vrms) and max forward current is reduced (50mA vs 100mA).
AI Summary

4N37 by onsemi: Optoisolator Transistor with Base Output 5300Vrms 1 Channel 6-DIP.

The 4N37M is onsemi's active, direct white-package replacement for the obsolete black-packaged 4N37. It matches the original's primary characteristics, including a minimum Current Transfer Ratio (CTR) of 100% at 10mA, but has slightly lower absolute maximum limits.

  • Direct modern replacement from the original manufacturer (onsemi)
  • Standard 6-DIP package is a physical drop-in with identical pinout
  • High reliability and widely available active design
  • Lower isolation voltage rating: 4170Vrms vs 5300Vrms on the obsolete original
  • Lower maximum DC forward current: 60mA vs 100mA on the obsolete original

Vishay's 4N37 is a widely used and highly reliable second-source alternative. It operates with the same pin configuration and package, providing strong isolation performance up to 5000Vrms.

  • Excellent safety isolation performance of 5000Vrms
  • Industry-standard 4N37 drop-in replacement from a tier-one optoelectronics brand
  • Very stable and actively produced with robust stock availability
  • Lower isolation rating: 5000Vrms vs 5300Vrms on the obsolete original
  • Lower maximum forward current: 50mA vs 100mA on the obsolete original
Lifecycle StatusObsoleteActiveActive
Market AvailabilityDiscontinuedIn stockIn stock
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Frequently asked questions

Yes. The onsemi 4N37 is marked obsolete, so the manufacturer has discontinued it and any remaining supply is limited to distributor stock. The qualified second sources on this page are active parts you can design in today.

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