FOD4208T Equivalent & Substitute Parts

Part Overview

The FOD4208T is an optoisolator with triac output manufactured by onsemi, designed for high-voltage isolation applications requiring 5000Vrms isolation rating. This component features a single-channel triac output in a 6-DIP through-hole package and is currently classified as obsolete. Due to its obsolete status, identifying equivalent and substitute parts is essential for design continuity and procurement planning in applications requiring triac-output optoisolators with comparable electrical and mechanical specifications.

Substiute Parts

FOD4208T

onsemiIn Stock: 787FOD4208T Datasheet

Current PartRFQ

FOD4208TV

onsemiIn Stock: 1746FOD4208TV Datasheet

SimilarRFQ

BRT13H

Vishay Semiconductor Opto DivisionIn Stock: 9130BRT13H Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the FOD4208T is determined by the following critical parameters that must be maintained or exceeded:

• Isolation Voltage: Minimum 5000Vrms required
• Output Type: Triac output mandatory
• Number of Channels: Single channel (1)
• Voltage - Off State: 800 V minimum
• Static dV/dt: 10kV/µs minimum
• Current - LED Trigger (Ift): 2mA maximum
• Current - Hold (Ih): 500µA
• Mounting Type: Through Hole
• Package Type: 6-DIP configuration

Two substitute parts meet these criteria with varying degrees of parameter alignment and product status differences.

Parameter Comparison

Engineering Selection Recommendations

FOD4208TV is the primary substitute for FOD4208T. Both parts are manufactured by onsemi with identical electrical specifications across all critical parameters. FOD4208TV maintains the same isolation voltage (5000Vrms), off-state voltage (800V), trigger current (2mA), hold current (500µA), forward voltage (1.28V), and forward current (30mA). The primary distinction is product status: FOD4208TV is active and carries expanded regulatory approvals including VDE certification and ROHS3 compliance, making it the preferred choice for new designs and ongoing production.

BRT13H from Vishay Semiconductor Opto Division is a secondary substitute option. It exceeds the isolation voltage requirement at 5300Vrms and maintains all critical switching parameters. However, BRT13H differs in three areas: (1) operating temperature range is narrower (-40°C to 100°C versus -55°C to 100°C), (2) maximum DC forward current is reduced to 20mA (versus 30mA), and (3) package dimensions differ (0.300" versus 0.400" DIP height). BRT13H is suitable for applications where the narrower temperature range and reduced forward current are acceptable, and where the smaller package footprint is compatible with PCB layout.

Frequently Asked Questions (FAQ)

Q: Can FOD4208TV directly replace FOD4208T without circuit modifications?

A: Yes. FOD4208TV is electrically and mechanically identical to FOD4208T across all specified parameters. Both use the same 6-DIP (0.400", 10.16mm) package and share identical electrical characteristics for isolation voltage, trigger current, hold current, and timing specifications. No circuit modifications are required.

Q: What are the key differences between FOD4208TV and BRT13H?

A: The primary differences are: (1) isolation voltage is higher in BRT13H (5300Vrms versus 5000Vrms), (2) operating temperature minimum is higher in BRT13H (-40°C versus -55°C), (3) maximum DC forward current is lower in BRT13H (20mA versus 30mA), and (4) package height differs (0.300" versus 0.400"). All other critical parameters including off-state voltage, trigger current, hold current, and dV/dt rating are identical.

Q: Is BRT13H suitable for applications requiring -55°C operation?

A: No. BRT13H operates from -40°C to 100°C, which does not meet the lower temperature requirement of -55°C specified for FOD4208T. Applications requiring -55°C minimum operating temperature must use FOD4208T or FOD4208TV.

Q: Does the smaller package size of BRT13H (0.300" DIP) affect PCB compatibility?

A: Yes. BRT13H uses a 6-DIP package with 0.300" height compared to the 0.400" height of FOD4208T and FOD4208TV. While both are 6-DIP configurations with the same pin pitch, the reduced height may affect PCB layout compatibility, particularly in applications with height constraints or existing footprints designed for the larger package. PCB layout verification is necessary before substitution.

Q: What is the significance of the regulatory approvals listed for each part?

A: Regulatory approvals indicate compliance with specific safety and environmental standards. FOD4208TV includes VDE certification in addition to cUL, FIMKO, and UL approvals, providing broader international recognition. BRT13H carries CQC and UL approvals. Both FOD4208TV and BRT13H are ROHS3 compliant, indicating compliance with restrictions on hazardous substances. Selection should consider the regulatory requirements of the target application and market.

Q: Can FOD4208T be used in new designs, or should FOD4208TV be specified instead?

A: FOD4208TV should be specified for new designs. FOD4208T is classified as obsolete, indicating discontinued manufacturing and potential long-term supply constraints. FOD4208TV is active with identical electrical and mechanical specifications, ensuring design continuity and supply reliability for current and future production.