FOD270LS Optoisolator Equivalent & Substitute Parts

Part Overview

The FOD270LS is an optoisolator with Darlington output and base connection, manufactured by onsemi. This component provides 5000Vrms isolation with a single channel configuration in an 8-SMD gull wing package. The product is currently obsolete, making equivalent and substitute parts necessary for ongoing system support and new design implementations. Substitute parts must maintain functional compatibility across isolation voltage, output type, channel configuration, and thermal operating range.

Substiute Parts

FOD270LS

onsemiIn Stock: 891FOD270LS Datasheet

Current PartRFQ

HCPL-270L-500E

Broadcom LimitedIn Stock: 841HCPL-270L-500E Datasheet

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HCPL-4701#300

Broadcom LimitedIn Stock: 927HCPL-4701#300 Datasheet

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HCPL-4701-320E

Broadcom LimitedIn Stock: 1045HCPL-4701-320E Datasheet

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HCPL-4701-360E

Broadcom LimitedIn Stock: 892HCPL-4701-360E Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the FOD270LS are grouped based on the following critical parameters that determine functional compatibility:

Primary Substitution Criteria:

• Number of Channels: Must be 1 channel
• Output Type: Must be Darlington with Base
• Voltage - Isolation: 5000Vrms or higher
• Current - Output / Channel: Minimum 60mA
• Mounting Type: Surface Mount
• Package / Case: 8-SMD, Gull Wing

Secondary Compatibility Factors:

• Operating Temperature Range: Must support the application's thermal requirements
• Current Transfer Ratio: Must meet or exceed minimum specifications
• Turn On / Turn Off Time: Must be compatible with circuit timing requirements

The substitute parts identified maintain the core electrical characteristics and physical form factor required for direct replacement in applications using the FOD270LS.

Parameter Comparison

Engineering Selection Recommendations

HCPL-4701-320E (Broadcom Limited)

This part is the primary substitute for the FOD270LS. It maintains 5000Vrms isolation voltage matching the original specification and includes Darlington with base output configuration. The part is in active production status with ROHS3 compliance. Operating temperature range is 0°C to 70°C, which is narrower than the original -40°C to 85°C range. This part is suitable for applications operating within the 0°C to 70°C thermal window.

HCPL-4701-360E (Broadcom Limited)

This part provides Darlington with base output in an active production status with ROHS3 compliance. Isolation voltage is 3750Vrms, which is lower than the FOD270LS 5000Vrms specification. This part is suitable only for applications where 3750Vrms isolation is sufficient. Operating temperature range is 0°C to 70°C.

HCPL-4701#300 (Broadcom Limited)

This part offers Darlington with base output configuration in active production status. Isolation voltage is 3750Vrms. The part is RoHS non-compliant. Operating temperature range is 0°C to 70°C. This part is suitable for applications where 3750Vrms isolation meets requirements and RoHS compliance is not mandated.

HCPL-270L-500E (Broadcom Limited)

This part provides 3750Vrms isolation with Darlington output (without base connection). The output type differs from the FOD270LS, which includes base connection. This part is suitable only for applications where base connection is not required. Operating temperature range is 0°C to 70°C.

Frequently Asked Questions (FAQ)

Q: Can HCPL-4701-320E directly replace FOD270LS in all applications?

A: HCPL-4701-320E matches the 5000Vrms isolation voltage and Darlington with base output type. However, the operating temperature range is 0°C to 70°C compared to FOD270LS at -40°C to 85°C. Direct replacement is valid only for applications operating within 0°C to 70°C.

Q: Why is HCPL-270L-500E listed as a substitute if it lacks base connection?

A: HCPL-270L-500E is included because it maintains the same isolation voltage class (3750Vrms), output current (60mA), and package form factor. However, the absence of base connection limits its use to applications where base drive is not required.

Q: What is the impact of lower isolation voltage in HCPL-4701-360E and HCPL-4701#300?

A: These parts provide 3750Vrms isolation versus the FOD270LS 5000Vrms. They are suitable only for applications where the lower isolation voltage meets safety and regulatory requirements. System-level isolation specifications must be verified before substitution.

Q: Are all substitute parts available in the same package?

A: All substitute parts use 8-SMD gull wing package configuration, matching the FOD270LS physical form factor. PCB layout compatibility is maintained across all listed substitutes.

Q: What compliance differences exist between substitute parts?

A: HCPL-4701-320E and HCPL-4701-360E are ROHS3 compliant. HCPL-4701#300 is RoHS non-compliant. All parts are REACH unaffected and classified as EAR99 for export control purposes.

Q: How do current transfer ratios compare across substitutes?

A: FOD270LS specifies 400% minimum at 500µA. HCPL-4701-320E, HCPL-4701-360E, and HCPL-4701#300 all specify 600% minimum at 500µA, providing higher current transfer efficiency. HCPL-270L-500E specifies 300% minimum at 1.6mA, which is lower and measured at different input current.

Q: What are the turn-on and turn-off time differences?

A: FOD270LS specifies 3µs turn-on and 50µs turn-off. HCPL-4701-320E, HCPL-4701-360E, and HCPL-4701#300 specify 3µs turn-on and 34µs turn-off, providing faster turn-off response. HCPL-270L-500E specifies 25µs turn-on and 50µs turn-off, with slower turn-on response.