SFH6138 Equivalent & Substitute Parts

Part Overview

The SFH6138 is an optoisolator with Darlington output and base connection, manufactured by Vishay Semiconductor Opto Division. This component provides 5300Vrms isolation in a through-hole 8-DIP package and is classified as obsolete. Due to its obsolete status and limited availability relative to active alternatives, equivalent substitute parts are necessary for new designs and ongoing production support.

Substiute Parts

SFH6138

Vishay Semiconductor Opto DivisionIn Stock: 2293SFH6138 Datasheet

Current PartRFQ

6N138

Fairchild SemiconductorIn Stock: 121646N138 Datasheet

MFR RecommendedRFQ

6N138

Fairchild SemiconductorIn Stock: 121646N138 Datasheet

MFR RecommendedRFQ

6N138(TP1,F)

Toshiba Semiconductor and StorageIn Stock: 12106N138(TP1,F) Datasheet

MFR RecommendedRFQ

6N138-000E

Broadcom LimitedIn Stock: 18296N138-000E Datasheet

MFR RecommendedRFQ

6N138-020E

Broadcom LimitedIn Stock: 8506N138-020E Datasheet

MFR RecommendedRFQ

6N139TVM

onsemiIn Stock: 10096N139TVM Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the SFH6138 is determined by the following critical parameters:

• Isolation Voltage: Minimum 5000Vrms (SFH6138 specifies 5300Vrms)
• Output Type: Darlington with Base configuration
• Number of Channels: Single channel
• Current - Output / Channel: 60mA minimum
• Mounting Type: Through Hole preferred for direct replacement
• Package / Case: 8-DIP form factor for PCB compatibility

Substitute parts are grouped into two categories:

Category A - Direct Through-Hole Replacements (8-DIP): Parts maintaining identical mounting and package specifications with isolation voltage at or above 5000Vrms.

Category B - Alternative Configuration: Parts with modified isolation voltage, package type, or operating temperature range that require design evaluation.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitutes (Active Status, Full Compatibility)

6N138-020E (Broadcom Limited) is the recommended primary substitute. It maintains 5000Vrms isolation, identical 8-DIP through-hole package, 60mA output current, and ROHS3 compliance. Operating temperature range is -40°C to 85°C, which is narrower than the SFH6138 but suitable for most industrial applications. This part is currently in active production status with 821 units in stock.

6N139TVM (onsemi) provides 5000Vrms isolation with enhanced current transfer ratio (500% minimum) and extended upper operating temperature to 100°C. The 8-DIP package is slightly larger (0.400" vs 0.300"), which may require PCB layout verification. This part is active with 973 units available.

Secondary Substitutes (Active Status, Parameter Deviations)

6N138-000E (Broadcom Limited) offers 3750Vrms isolation, which is below the SFH6138 specification. Use only in applications where isolation voltage requirement is 3750Vrms or lower. This part is active with ROHS3 compliance and 1794 units in stock.

6N138(TP1,F) (Toshiba Semiconductor and Storage) is a surface-mount variant with 2500Vrms isolation. This part is not suitable as a direct replacement due to reduced isolation voltage and surface-mount package type. Use only if PCB redesign for SMD assembly is acceptable and isolation voltage of 2500Vrms is sufficient.

Avoid

6N138 (Fairchild Semiconductor) is obsolete and RoHS non-compliant, offering no advantage over the original SFH6138 for new designs.

Frequently Asked Questions (FAQ)

Q: Can 6N138-020E directly replace SFH6138 on existing PCBs?

A: Yes. The 6N138-020E maintains the same 8-DIP (0.300", 7.62mm) through-hole package and pinout compatibility. No PCB modifications are required. The 5000Vrms isolation meets or exceeds most application requirements, though designs specifically requiring 5300Vrms isolation should be evaluated.

Q: What is the difference between 6N138-020E and 6N138-000E?

A: The primary difference is isolation voltage: 6N138-020E provides 5000Vrms while 6N138-000E provides 3750Vrms. Both share identical package, output current, and operating temperature range. Select based on your circuit's isolation voltage requirement.

Q: Why is 6N139TVM larger (0.400" vs 0.300")?

A: The 6N139TVM uses an 8-MDIP package format, which is a standard through-hole variant with wider pin spacing. This may require PCB layout verification to confirm clearance and trace routing compatibility, but electrical performance is equivalent.

Q: Is 6N138(TP1,F) a suitable replacement?

A: No, not as a direct replacement. This part is a surface-mount component (8-SMD) with reduced isolation voltage (2500Vrms). It requires PCB redesign for SMD assembly and is only suitable if your application's isolation voltage requirement is 2500Vrms or lower.

Q: Which substitute has the best current transfer ratio?

A: 6N139TVM offers 500% minimum current transfer ratio compared to 300% for other substitutes. This higher ratio provides improved switching performance and noise margin in digital isolation applications.

Q: Are all active substitutes RoHS compliant?

A: All active substitutes except 6N138 (Fairchild) are RoHS compliant. 6N138-020E, 6N138-000E, and 6N139TVM are ROHS3 compliant. 6N138(TP1,F) is RoHS compliant. The original 6N138 from Fairchild is RoHS non-compliant and should not be used in new designs.

Q: What is the operating temperature range difference?

A: SFH6138 operates -55°C to 100°C. Most active substitutes operate -40°C to 85°C, except 6N139TVM which extends to 100°C. Verify your application's temperature requirements before selection.