MOC8021SD Equivalent & Substitute Parts

Part Overview

The MOC8021SD is a high-voltage optoisolator with Darlington output manufactured by onsemi, designed for galvanic isolation applications requiring 5300Vrms isolation voltage. This component features a single channel configuration in a 6-SMD surface mount package with a maximum output current of 150mA per channel.

The MOC8021SD is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications currently utilizing this component.

Substiute Parts

MOC8021SD

onsemiIn Stock: 897MOC8021SD Datasheet

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MOC8021SM

onsemiIn Stock: 2066MOC8021SM Datasheet

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MOC8021SMT&R

Isocom Components 2004 LTDIn Stock: 1197MOC8021SMT&R Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MOC8021SD is determined by the following critical parameters:

• Output Type: Must be Darlington configuration
• Number of Channels: Must be single channel (1)
• Package / Case: Must be 6-SMD, Gull Wing surface mount
• Mounting Type: Must be Surface Mount
• Voltage - Output (Max): Must support minimum 50V
• Current - Output / Channel: Must support minimum 150mA
• Voltage - Isolation: Must meet or exceed 5300Vrms isolation requirement
• Operating Temperature Range: Must encompass or overlap the -55°C ~ 100°C range

The MOC8021SM from onsemi meets all critical substitution parameters with active product status. The MOC8021SMT&R from Isocom Components 2004 LTD shares the same package and Darlington output configuration but has reduced isolation voltage (7.5Vpk) and lower maximum output voltage (35V), making it unsuitable for applications requiring the full 5300Vrms isolation specification.

Parameter Comparison

Engineering Selection Recommendations

MOC8021SM (onsemi) is the primary substitute for MOC8021SD. Both components are manufactured by onsemi and share identical Darlington output configuration, package type, and current handling specifications. The MOC8021SM maintains active product status, ensuring ongoing availability and supply chain support. The isolation voltage of 4170Vrms is lower than the MOC8021SD specification of 5300Vrms; applications requiring the full 5300Vrms isolation margin should evaluate whether the reduced isolation voltage is acceptable for their specific circuit requirements. Both components carry REACH Unaffected status and EAR99 ECCN classification.

MOC8021SMT&R (Isocom Components 2004 LTD) is not recommended as a direct substitute. While it shares the same package and Darlington output type, the isolation voltage specification of 7.5Vpk is substantially lower than the MOC8021SD requirement of 5300Vrms, and the maximum output voltage of 35V does not meet the 50V specification. This component is suitable only for applications with significantly reduced isolation voltage requirements.

Frequently Asked Questions (FAQ)

Q: Can MOC8021SM directly replace MOC8021SD in existing designs?

A: MOC8021SM is mechanically and functionally compatible with MOC8021SD in terms of package, pinout, and output current specifications. The primary difference is isolation voltage: MOC8021SM provides 4170Vrms versus MOC8021SD's 5300Vrms. Direct replacement is possible if your application does not require the full 5300Vrms isolation margin. Verify isolation voltage requirements in your circuit design before substitution.

Q: Why is MOC8021SMT&R not suitable as a substitute?

A: MOC8021SMT&R has isolation voltage of 7.5Vpk and maximum output voltage of 35V, both significantly below MOC8021SD specifications (5300Vrms isolation, 50V output). This component is designed for different application classes and does not meet the electrical requirements of MOC8021SD-based designs.

Q: What are the key parameters that determine substitution compatibility?

A: Substitution compatibility is determined by: Darlington output type, single channel configuration, 6-SMD Gull Wing package, surface mount mounting type, minimum 50V output voltage capability, minimum 150mA output current per channel, and isolation voltage requirements. All substitute parts must maintain these specifications.

Q: Are there temperature range considerations when substituting?

A: MOC8021SD operates from -55°C to 100°C. MOC8021SM operates from -40°C to 100°C, providing a narrower low-temperature range. Applications requiring operation below -40°C must use MOC8021SD or equivalent parts with extended low-temperature specifications.

Q: What is the packaging difference between MOC8021SM and MOC8021SMT&R?

A: MOC8021SM is supplied in Bulk packaging, while MOC8021SMT&R is supplied in Tape & Reel (TR) format. Both use identical 6-SMD Gull Wing surface mount packages. Packaging format affects handling and automated assembly compatibility but does not impact electrical performance.