FOD4118SD Equivalent & Substitute Parts

Part Overview

The FOD4118SD is an optoisolator with triac output manufactured by onsemi, designed for high-voltage isolation applications. This 6-SMD surface mount component provides 5000Vrms isolation with integrated zero-crossing detection, making it suitable for AC power control circuits. The part is currently active in production with full inventory availability. Equivalent and substitute parts are identified based on matching electrical characteristics, isolation voltage ratings, output type, and package compatibility to ensure functional interchangeability in circuit designs.

Substiute Parts

FOD4118SD

onsemiIn Stock: 3384FOD4118SD Datasheet

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BRT23F

Vishay Semiconductor Opto DivisionIn Stock: 1896BRT23F Datasheet

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BRT23H

Vishay Semiconductor Opto DivisionIn Stock: 1576BRT23H Datasheet

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IL4108-X007T

Vishay Semiconductor Opto DivisionIn Stock: 3513IL4108-X007T Datasheet

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IL4108-X009T

Vishay Semiconductor Opto DivisionIn Stock: 1341IL4108-X009T Datasheet

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IL4118-X009T

Vishay Semiconductor Opto DivisionIn Stock: 1847IL4118-X009T Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the FOD4118SD are identified based on the following critical parameters that determine functional interchangeability:

Primary Substitution Criteria:

• Output Type: Triac
• Isolation Voltage: Minimum 5000Vrms
• Number of Channels: 1
• Zero Crossing Circuit: Yes
• Voltage - Off State: 800 V
• Static dV/dt: 10kV/µs or higher
• Operating Temperature Range: -55°C ~ 100°C
• Mounting Type: Surface Mount
• Package Type: 6-SMD configuration

Substitute Parts Identified:

Group 1 - Direct SMD Surface Mount Substitutes (IL4108 and IL4118 Series):

• IL4108-X007T (Vishay)
• IL4108-X009T (Vishay)
• IL4118-X009T (Vishay)

These parts meet all primary substitution criteria with 5300Vrms isolation voltage, surface mount 6-SMD packaging, and triac output with zero-crossing detection.

Group 2 - DIP Package Alternatives (BRT23 Series):

• BRT23F (Vishay)
• BRT23H (Vishay)

These parts provide triac output with 800V off-state voltage but use 6-DIP tube packaging instead of surface mount SMD. Package type differs from the main part.

Parameter Comparison

Engineering Selection Recommendations

For Direct Surface Mount Substitution (Recommended for PCB-level replacement):

The IL4118-X009T offers the closest electrical match to the FOD4118SD. Both parts share identical LED trigger current specifications (1.3mA maximum), matching hold current (500µA), and identical static dV/dt rating (10kV/µs). The IL4118-X009T provides higher isolation voltage (5300Vrms versus 5000Vrms), which provides additional safety margin. Both parts are ROHS3 compliant, MSL Level 1, and maintain the same operating temperature range. The IL4118-X009T is approved by BSI, CSA, cUR, FIMKO, and UR agencies.

The IL4108-X007T and IL4108-X009T are functionally equivalent alternatives with higher maximum forward current (60mA versus 30mA) and faster turn-on time (35µs versus 60µs). These parts require higher LED trigger current (2mA maximum) and are approved by CSA and UR agencies.

For Package-Agnostic Substitution (When through-hole mounting is acceptable):

The BRT23F and BRT23H from Vishay provide triac output with 800V off-state voltage in 6-DIP through-hole packaging. These parts are suitable only when circuit board layout permits through-hole component replacement and when the different package footprint is acceptable. Detailed electrical specifications for these parts are not provided in the available data.

All substitute parts maintain ROHS3 compliance, MSL Level 1 moisture sensitivity, and active product status matching the FOD4118SD.

Frequently Asked Questions (FAQ)

Q: Can IL4118-X009T directly replace FOD4118SD on the same PCB?

A: Yes, the IL4118-X009T is a direct surface mount substitute. Both use 6-SMD gull wing packaging with identical footprints. Electrical characteristics are compatible, with the IL4118-X009T providing higher isolation voltage (5300Vrms) and matching LED trigger current (1.3mA). No circuit modifications are required.

Q: What is the difference between IL4108 and IL4118 series substitutes?

A: The IL4108-X007T and IL4108-X009T differ from IL4118-X009T in LED trigger current specification (2mA maximum versus 1.3mA) and hold current (500µA versus 200µA). The IL4108 series requires higher input current but offers faster turn-on time (35µs versus 60µs). Both series provide 5300Vrms isolation and are suitable substitutes based on isolation voltage and triac output type.

Q: Are BRT23F and BRT23H suitable replacements for surface mount applications?

A: No. BRT23F and BRT23H use 6-DIP through-hole packaging, not surface mount. These parts are suitable only for applications where through-hole mounting is acceptable and PCB layout can accommodate the different footprint. They are not direct replacements for surface mount designs.

Q: What compliance certifications apply to all substitute parts?

A: All substitute parts (IL4108-X007T, IL4108-X009T, IL4118-X009T, BRT23F, BRT23H) are ROHS3 compliant with MSL Level 1 moisture sensitivity rating. The IL4118-X009T carries additional approvals from BSI, CSA, cUR, FIMKO, and UR. The IL4108 series carries CSA and UR approvals. All parts maintain active product status.

Q: Does higher isolation voltage (5300Vrms) in substitute parts affect circuit design?

A: No. Higher isolation voltage in substitute parts (IL4108 and IL4118 series at 5300Vrms versus FOD4118SD at 5000Vrms) provides additional safety margin and is fully compatible with designs specified for 5000Vrms isolation. This represents an improvement in isolation capability with no negative impact on circuit performance.

Q: What is the maximum forward current difference between FOD4118SD and substitute parts?

A: FOD4118SD specifies 30mA maximum DC forward current. IL4108-X007T, IL4108-X009T, and IL4118-X009T all specify 60mA maximum. This higher rating in substitute parts provides additional design margin and does not affect compatibility. Circuits designed for 30mA operation will function correctly with parts rated for 60mA.