HCPL-4731#520 Equivalent & Substitute Parts

Part Overview

The HCPL-4731#520 is a 2-channel optoisolator with Darlington output, rated for 5000Vrms isolation voltage. Manufactured by Broadcom Limited, this component is designed for applications requiring high-voltage isolation with dual-channel switching capability. The part is discontinued at DiGi Electronics, necessitating identification of functionally equivalent alternatives that maintain electrical and mechanical compatibility within acceptable parameter ranges.

Substiute Parts

HCPL-4731#520

Broadcom LimitedIn Stock: 1004HCPL-4731#520 Datasheet

Current PartRFQ

HCPL-4731-520E

Broadcom LimitedIn Stock: 1088HCPL-4731-520E Datasheet

DirectRFQ

HCPL2730S

Fairchild SemiconductorIn Stock: 2300HCPL2730S Datasheet

MFR RecommendedRFQ

HCPL2730SD

onsemiIn Stock: 4478HCPL2730SD Datasheet

MFR RecommendedRFQ

HCPL2731S

onsemiIn Stock: 1131HCPL2731S Datasheet

MFR RecommendedRFQ

HCPL2731SD

onsemiIn Stock: 3156HCPL2731SD Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the HCPL-4731#520 is determined by the following critical parameters:

Primary Substitution Criteria:

• Number of Channels: 2 (fixed requirement)
• Output Type: Darlington (fixed requirement)
• Package / Case: 8-SMD, Gull Wing (fixed requirement)
• Voltage - Isolation: 5000Vrms minimum (primary electrical constraint)
• Current - Output / Channel: 60mA minimum (fixed requirement)
• Input Type: DC (fixed requirement)

Secondary Compatibility Parameters:

• Current Transfer Ratio: Minimum 600% @ 500µA
• Voltage - Output (Max): 18V minimum
• Operating Temperature: Must encompass 0°C ~ 70°C range

Substitute parts are grouped into two categories:

Category A - Direct Equivalents (5000Vrms Isolation): Parts maintaining the full 5000Vrms isolation specification with identical electrical performance characteristics.

Category B - Functional Alternatives (2500Vrms Isolation): Parts with reduced isolation voltage (2500Vrms) that maintain all other electrical and mechanical parameters. These are suitable for applications where the full 5000Vrms isolation is not required.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation: HCPL-4731-520E

The HCPL-4731-520E is the direct equivalent to the HCPL-4731#520. Both parts are manufactured by Broadcom Limited and share identical electrical specifications including 5000Vrms isolation voltage, current transfer ratio range (600% to 8000% @ 500µA), and output voltage rating (18V maximum). The HCPL-4731-520E is currently in active product status with ROHS3 compliance, making it the preferred replacement for discontinued inventory.

Secondary Recommendation: HCPL2731SD

The HCPL2731SD, manufactured by onsemi, provides functional substitution with the following considerations:

• Maintains 2-channel Darlington output configuration
• Maintains 8-SMD Gull Wing package compatibility
• Maintains 60mA output current per channel
• Maintains 18V maximum output voltage
• Isolation voltage reduced to 2500Vrms (50% of original specification)
• Current transfer ratio minimum of 500% @ 1.6mA (lower test current than original)
• Extended operating temperature range (-40°C ~ 85°C)
• ROHS3 compliant
• Product status: Obsolete

This part is suitable for applications where 2500Vrms isolation meets system requirements and where the extended temperature range provides operational advantage.

Alternative Consideration: HCPL2731S

The HCPL2731S offers identical electrical characteristics to HCPL2731SD with the same isolation voltage reduction and performance parameters. Product status is obsolete. Selection between HCPL2731S and HCPL2731SD depends on packaging and supply chain availability.

Not Recommended: HCPL2730S and HCPL2730SD

These parts reduce the maximum output voltage to 7V, which is below the 18V specification of the original part. While they maintain 2500Vrms isolation and 60mA output current, the reduced output voltage rating creates a functional limitation that may not be acceptable for applications designed around the 18V capability.

Frequently Asked Questions (FAQ)

Q: Can HCPL2730S replace HCPL-4731#520?

A: HCPL2730S maintains the 2-channel Darlington configuration, 8-SMD Gull Wing package, and 60mA output current. However, it reduces the maximum output voltage from 18V to 7V and the isolation voltage from 5000Vrms to 2500Vrms. Substitution is only valid if your application operates within these reduced specifications.

Q: What is the key difference between HCPL2731SD and HCPL2730SD?

A: Both parts share identical isolation voltage (2500Vrms), package type (8-SMD Gull Wing), and output current (60mA). The primary difference is maximum output voltage: HCPL2731SD supports 18V while HCPL2730SD supports only 7V. Select HCPL2731SD if your circuit requires higher output voltage capability.

Q: Is HCPL-4731-520E a direct replacement for HCPL-4731#520?

A: Yes. HCPL-4731-520E is the active product equivalent manufactured by Broadcom Limited with identical electrical specifications. The primary difference is packaging format (Tape & Reel versus bulk) and product status (Active versus Discontinued). Electrical performance and pin compatibility are identical.

Q: Why do substitute parts show reduced isolation voltage?

A: The HCPL-4731#520 operates at 5000Vrms isolation, which is a premium specification. Alternative parts from other manufacturers (onsemi, Fairchild Semiconductor) in the same package and channel configuration are available at 2500Vrms isolation. Selection depends on whether your application requires the full 5000Vrms isolation or if 2500Vrms meets system requirements.

Q: Are the obsolete parts (HCPL2731SD, HCPL2731S, HCPL2730SD) still available?

A: Product status indicates these parts are obsolete at the manufacturer level. However, inventory may exist through authorized distributors. Verify current availability before committing to designs using obsolete components. The HCPL-4731-520E (active status) is the recommended long-term solution.

Q: What is the difference between HCPL2731S and HCPL2731SD?

A: Both parts are manufactured by onsemi with identical electrical specifications. HCPL2731SD is supplied in Cut Tape (CT) & Digi-Reel packaging, while HCPL2731S packaging is not specified. Electrical performance is identical; selection depends on packaging and supply availability.

Q: Does operating temperature range affect substitution?

A: The original HCPL-4731#520 operates from 0°C to 70°C. Substitute parts HCPL2731SD, HCPL2731S, HCPL2730SD, and HCPL2730S extend this to -40°C to 85°C. If your application operates within the original 0°C to 70°C range, the extended temperature capability of substitutes provides additional margin. If your application requires operation below 0°C or above 70°C, substitutes enable expanded operating conditions.