6N138 Optoisolator Darlington with Base Output

Part Overview

The 6N138 is a single-channel optoisolator with Darlington output and base connection, designed for high-voltage isolation applications. Manufactured by Vishay Semiconductor Opto Division, this component provides 5300Vrms isolation with a 1 Channel 8-DIP package configuration. The part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support. Substitute parts must maintain functional compatibility across isolation voltage, output characteristics, and package form factor while meeting current availability and compliance requirements.

Substiute Parts

6N138

Vishay Semiconductor Opto DivisionIn Stock: 121206N138 Datasheet

Current PartRFQ

6N138

Fairchild SemiconductorIn Stock: 121646N138 Datasheet

MFR RecommendedRFQ

6N138

Fairchild SemiconductorIn Stock: 121646N138 Datasheet

MFR RecommendedRFQ

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

Key Parameters

Substitute Part Grouping Explanation

Substitution for the 6N138 is determined by the following critical parameters:

Primary Compatibility Criteria:

• Number of Channels: 1 (single channel required)
• Output Type: Darlington with Base (functional output configuration)
• Package / Case: 8-DIP (0.300", 7.62mm) (mechanical and electrical interface)
• Mounting Type: Through Hole (PCB assembly compatibility)
• Input Type: DC (signal input method)
• Voltage - Isolation: Minimum 5000Vrms (isolation performance threshold)
• Current - Output / Channel: 60mA (output drive capability)
• Voltage - Output (Max): 7V (output voltage rating)

Secondary Compatibility Criteria:

• Current Transfer Ratio (Min): 300% @ 1.6mA (optical coupling efficiency)
• Operating Temperature Range: Must encompass or exceed -55°C ~ 100°C
• RoHS Compliance: ROHS3 Compliant preferred for new designs

Substitute parts are grouped into two categories: direct equivalents maintaining identical isolation voltage (5000Vrms or higher) and through-hole 8-DIP packaging, and alternative form factors (surface mount) that maintain electrical function but differ in mounting method.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitutes (Direct Replacement - Through Hole 8-DIP):

6N138-020E (Broadcom Limited) is the primary substitute for the 6N138. This part maintains 5000Vrms isolation voltage, identical 8-DIP through-hole package, 60mA output current, and 7V maximum output voltage. The part is currently active in production with ROHS3 compliance, addressing the obsolescence of the original Vishay component. Operating temperature range of -40°C ~ 85°C covers most industrial applications, though it does not extend to the full -55°C lower limit of the original part.

6N138-000E (Broadcom Limited) provides an alternative through-hole 8-DIP option with 3750Vrms isolation voltage. This part is suitable for applications where isolation voltage requirements are 3750Vrms or lower. It maintains active production status and ROHS3 compliance. The reduced isolation voltage makes this option applicable only to designs with lower isolation requirements than the original 5300Vrms specification.

6N138 (Fairchild Semiconductor) represents a historical equivalent with 5000Vrms isolation in 8-DIP through-hole package. This part is obsolete and RoHS non-compliant, making it unsuitable for new designs despite electrical compatibility.

Alternative Form Factor (Surface Mount):

6N138(TP1,F) (Toshiba Semiconductor) provides equivalent functionality in 8-SMD surface-mount package. This part is active in production with RoHS compliance. The 2500Vrms isolation voltage is lower than the original specification and suitable only for reduced isolation requirements. The surface-mount package requires different PCB assembly processes and cannot be used as a direct mechanical replacement in through-hole designs.

Compliance and Availability:

For new designs, select 6N138-020E (Broadcom) as the primary substitute. This part maintains the highest isolation voltage (5000Vrms) among active components, preserves the through-hole 8-DIP package form factor, and meets current RoHS3 compliance requirements. Broadcom parts are currently in stock with active production status.

For applications with reduced isolation voltage requirements (3750Vrms or lower), 6N138-000E (Broadcom) is acceptable and maintains identical package compatibility.

Surface-mount alternatives should be considered only when PCB design permits SMD assembly and isolation voltage requirements are 2500Vrms or lower.

Frequently Asked Questions (FAQ)

Q: Can 6N138-020E directly replace the original 6N138 in existing PCB designs?

A: Yes. The 6N138-020E maintains identical 8-DIP through-hole package dimensions (0.300", 7.62mm), pin configuration, and electrical output characteristics (60mA, 7V maximum). The 5000Vrms isolation voltage is slightly lower than the original 5300Vrms but meets the same functional requirements for most applications. Verify that your circuit design does not specifically require the extended -55°C lower operating temperature limit, as the Broadcom part operates from -40°C.

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

A: Both parts are Broadcom optoisolators in 8-DIP through-hole packages with identical output characteristics (60mA, 7V). The primary difference is isolation voltage: 6N138-020E provides 5000Vrms isolation, while 6N138-000E provides 3750Vrms isolation. Select 6N138-020E for applications requiring higher isolation voltage. Both parts are currently active in production and RoHS3 compliant.

Q: Why is the Toshiba 6N138(TP1,F) listed as a substitute if it uses surface-mount packaging?

A: The Toshiba part maintains electrical equivalence in output type (Darlington with Base), channel count (1), and output current (60mA). However, the 8-SMD surface-mount package is mechanically incompatible with through-hole PCB designs. This part is listed as an alternative only for new designs where surface-mount assembly is specified. The 2500Vrms isolation voltage is also lower than the original specification.

Q: Is the Fairchild 6N138 a viable substitute?

A: The Fairchild 6N138 is electrically equivalent with 5000Vrms isolation and 8-DIP through-hole packaging. However, this part is obsolete and RoHS non-compliant. It is not recommended for new designs. Use Broadcom 6N138-020E instead, which provides equivalent isolation voltage with active production status and current compliance certifications.

Q: What happens if my application requires the full -55°C to 100°C operating temperature range?

A: The Broadcom substitutes (6N138-020E and 6N138-000E) operate from -40°C to 85°C, which does not cover the full lower temperature range of the original Vishay part. If your application requires operation below -40°C or above 85°C, verify that the reduced temperature range is acceptable for your specific use case. No active substitute parts are available that maintain both the original temperature range and current compliance status.

Q: Are all substitute parts RoHS compliant?

A: The Broadcom parts (6N138-020E and 6N138-000E) and Toshiba part (6N138(TP1,F)) are RoHS compliant. The Fairchild 6N138 is RoHS non-compliant and should not be used in new designs subject to RoHS requirements.

Q: Can I use 6N138-000E if my design only requires 3750Vrms isolation?

A: Yes. If your circuit design specifies 3750Vrms isolation or lower, the 6N138-000E is a suitable substitute. It maintains the 8-DIP through-hole package, 60mA output current, and 7V maximum output voltage. This part is currently active in production with ROHS3 compliance and represents a cost-effective option for lower isolation voltage applications.