VO4258D Optoisolator Triac Output Equivalent & Substitute Parts

Part Overview

The VO4258D is an optoisolator with triac output manufactured by Vishay Semiconductor Opto Division. This component provides 5300Vrms isolation in a 6-DIP through-hole package and is designed for applications requiring galvanic isolation with triac switching capability. The part is currently active in production with 2616 units in stock. Substitute parts may be required due to supply constraints, regional availability, or design flexibility in applications where electrical parameters fall within acceptable tolerance ranges.

Substiute Parts

VO4258D

Vishay Semiconductor Opto DivisionIn Stock: 2650VO4258D Datasheet

Current PartRFQ

FOD4208

onsemiIn Stock: 2386FOD4208 Datasheet

MFR RecommendedRFQ

FOD4218

onsemiIn Stock: 1215FOD4218 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the VO4258D is determined by the following critical parameters:

• Output Type: Must be Triac
• Number of Channels: Must be 1
• Package / Case: Must be 6-DIP (0.300", 7.62mm)
• Mounting Type: Must be Through Hole
• Voltage - Isolation: Minimum 5000Vrms (VO4258D specifies 5300Vrms)
• Operating Temperature Range: Must support -55°C ~ 100°C
• RoHS Compliance: ROHS3 Compliant

The substitute parts FOD4208 and FOD4218 (both manufactured by onsemi) meet all critical substitution criteria. Both parts feature identical package geometry, mounting type, channel configuration, and temperature operating range. The isolation voltage of 5000Vrms on substitute parts is within acceptable parameters for applications designed for the VO4258D, as the substitute parts maintain the same voltage class and safety certifications.

Parameter Comparison

Engineering Selection Recommendations

Both FOD4208 and FOD4218 are active production parts with established supply availability. Selection between these substitutes and the VO4258D should be based on the following factors:

VO4258D (Vishay): Provides higher isolation voltage specification (5300Vrms) and higher maximum DC forward current (60 mA). Suitable for applications requiring maximum isolation margin or higher LED drive current capability.

FOD4208 (onsemi): Offers higher static dV/dt rating (10kV/µs versus 5kV/µs) and higher maximum LED trigger current (2mA). Appropriate for applications with faster transient switching requirements or where higher trigger current is acceptable.

FOD4218 (onsemi): Provides the lowest maximum LED trigger current (1.3mA) among the three options. Suitable for applications requiring minimal LED drive current or where power consumption is a design constraint.

All three parts carry equivalent safety certifications (BSI, cUR, FIMKO, UR for VO4258D; cUL, FIMKO, UL for FOD4208 and FOD4218) and comply with ROHS3 requirements. Pin-to-pin compatibility and 6-DIP package geometry are identical across all three parts.

Frequently Asked Questions (FAQ)

Q: Can FOD4208 or FOD4218 be used as direct replacements for VO4258D in existing designs?

A: Yes, both parts are pin-compatible and functionally equivalent for triac output optoisolator applications. The 6-DIP package geometry is identical, and all three parts operate within the same temperature range (-55°C to 100°C). Verify that your application can accommodate the parameter differences listed in the comparison table, particularly the isolation voltage specification (5000Vrms for substitutes versus 5300Vrms for VO4258D) and LED trigger current requirements.

Q: What is the difference between FOD4208 and FOD4218?

A: The primary difference is the maximum LED trigger current specification: FOD4208 specifies 2mA maximum, while FOD4218 specifies 1.3mA maximum. Both parts share identical isolation voltage, off-state voltage, static dV/dt rating, hold current, turn-on time, forward voltage, and operating temperature range. Selection depends on your circuit's LED drive current requirements.

Q: Are there any compliance or certification differences between these parts?

A: All three parts are ROHS3 compliant. VO4258D carries BSI, cUR, FIMKO, and UR approvals. FOD4208 and FOD4218 carry cUL, FIMKO, and UL approvals. Verify that the certification requirements for your application are met by the selected part.

Q: What is the significance of the static dV/dt rating difference?

A: The static dV/dt rating indicates the maximum rate of voltage change the triac output can withstand without false triggering. VO4258D specifies 5kV/µs minimum, while FOD4208 and FOD4218 specify 10kV/µs minimum. The higher rating on onsemi parts provides greater immunity to fast transient voltage changes in the circuit.

Q: Can I use these parts interchangeably in high-isolation applications?

A: The VO4258D provides 5300Vrms isolation, while FOD4208 and FOD4218 provide 5000Vrms isolation. Both ratings fall within the same isolation class. Confirm that your application's isolation voltage requirement does not exceed 5000Vrms before substituting with onsemi parts.