MOC3021 Optoisolator Triac Output Equivalent & Substitute Parts

Part Overview

The MOC3021 is a 6-DIP optoisolator with triac output, designed for galvanic isolation applications requiring 5300Vrms isolation voltage. Manufactured by onsemi, this component features a single-channel triac output with no zero-crossing circuit. The MOC3021 is currently classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and procurement planning.

Substiute Parts

MOC3021

onsemiIn Stock: 247566MOC3021 Datasheet

Current PartRFQ

MOC3021M

Fairchild SemiconductorIn Stock: 125239MOC3021M Datasheet

DirectRFQ

MOC3021

onsemiIn Stock: 247566MOC3021 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the MOC3021 is determined by the following critical parameters:

• Output Type: Must be Triac
• Package / Case: Must be 6-DIP (0.300", 7.62mm)
• Mounting Type: Must be Through Hole
• Number of Channels: Must be 1
• Voltage - Isolation: Minimum 5000Vrms (MOC3021 specifies 5300Vrms)
• Voltage - Off State: 400 V
• Current - LED Trigger (Ift) (Max): 15mA
• Current - DC Forward (If) (Max): 50 mA

The MOC3021M from Fairchild Semiconductor meets these substitution criteria with compatible electrical and mechanical specifications, enabling direct functional replacement in existing circuit designs.

Parameter Comparison

Engineering Selection Recommendations

The MOC3021M (Fairchild Semiconductor) is the qualified substitute for the obsolete MOC3021. Both components share identical package geometry, pinout, and core electrical specifications. The MOC3021M maintains active product status with current manufacturing support and inventory availability.

The MOC3021M carries multiple approval certifications including CQC, CSA, TUV, UL, and VDE, providing compliance documentation for regulated applications. The isolation voltage specification of 5000Vrms on the MOC3021M remains within acceptable parameters for applications designed around the MOC3021's 5300Vrms rating.

Frequently Asked Questions (FAQ)

Q: Can MOC3021M directly replace MOC3021 in existing designs?

A: Yes. Both components feature identical 6-DIP package geometry, pinout configuration, and matching electrical specifications for LED trigger current, forward current, and off-state voltage. The MOC3021M is pin-compatible and functionally equivalent.

Q: What is the difference in isolation voltage between MOC3021 and MOC3021M?

A: The MOC3021 specifies 5300Vrms isolation voltage, while the MOC3021M specifies 5000Vrms. Both exceed 5000Vrms minimum isolation requirements. Applications designed for the MOC3021 operate within the MOC3021M's isolation rating.

Q: Are there differences in hold current specifications?

A: The MOC3021 specifies 100µA hold current, while the MOC3021M specifies 250µA typical hold current. This difference does not affect substitution compatibility for standard triac output applications.

Q: What certifications does the MOC3021M carry?

A: The MOC3021M holds CQC, CSA, TUV, UL, and VDE approvals, supporting use in regulated and safety-critical applications.

Q: Is the MOC3021 still available for procurement?

A: The MOC3021 is classified as obsolete. The MOC3021M is the active equivalent with current manufacturing and distribution support.