Is there a pin-compatible replacement for MOC3021?

Yes, MOC3023 is a pin-compatible replacement for MOC3021. It shares the same DIP-6 package, pinout, and critical electrical characteristics.

What risks should I check before replacing MOC3021?

The main risk is choosing a zero-crossing driver (like MOC3041/MOC3043) instead of a non-zero-crossing one. This will not work for inductive loads (motors) or phase-angle control (dimmers). Always verify the output type.

MOC3021 Alternatives, Datasheet & Cross Reference | ISOCOM

MOC3021 is a popular 400V non-zero-crossing triac driver optocoupler in a DIP-6 package, widely used for interfacing logic to AC power loads. Find pin-compatible replacements and functional alternatives for your design.

AI replacement insight

Electrical riskhigh

Using a zero-crossing part for an inductive load can cause malfunction or failure.

Package risklow

Most alternatives are in the same DIP-6 package.

Can it be replaced directly?

Yes, MOC3023 is a direct, pin-compatible replacement for MOC3021. It belongs to the same non-zero-crossing family and has a more sensitive input.

Best replacement path

MOC3023 is the recommended replacement, offering pin compatibility and improved input sensitivity (5mA vs 15mA IFT).

Main risk

The primary risk is accidentally selecting a zero-crossing driver (e.g., MOC304x series), which is not suitable for inductive loads or phase control applications.

Recommended alternatives

Pin-compatible alternative with a more sensitive input (5mA vs 15mA IFT), suitable for all MOC3021 applications.

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Alternative comparison matrix

Feature / factor	MOC3021	MOC3023	MOC3083-JSM	MOC3041M(UMW)	Compatibility / risk
Package	DIP-6	DIP-6	DIP-6	DIP-6	DIP-6 — Package matches, ensuring form and fit.; MOC3083-JSM: Package matches.; MOC3041M(UMW): Package matches.
Output Type	Triac, Non-Zero Crossing	Triac, Non-Zero Crossing	Triac, Zero Crossing	Triac, Zero Crossing	Triac, Non-Zero Crossing / Triac, Zero Crossing — Functionally identical random-phase triac driver output.; MOC3083-JSM: Functionally different; not for inductive loads or phase control.; MOC3041M(UMW): Functionally different; not for inductive loads or phase control.
Current	15mA	5mA	5mA	15mA	5mA / 15mA — More sensitive input (lower IFT) is a safe upgrade.; MOC3083-JSM: More sensitive input (lower IFT) is an upgrade.; MOC3041M(UMW): LED trigger current (IFT) matches.
Voltage	5000Vrms	5000Vrms	800V	400V	5000Vrms / 800V / 400V — Isolation voltage is identical.; MOC3083-JSM: Higher VDRM provides more margin for 240V AC lines.; MOC3041M(UMW): Peak off-state voltage (VDRM) matches.

Application & sourcing insights

Questions & answers

The best alternative to MOC3021 is MOC3023. It is pin-compatible, has the same non-zero-crossing function, and features a more sensitive input which is a safe upgrade.