MMQA20VT1 Equivalent & Substitute Parts

Part Overview

The MMQA20VT1 is a transient voltage suppressor (TVS) diode manufactured by onsemi, designed for general-purpose overvoltage protection in surface-mount applications. This component features a 15V reverse standoff voltage with 28.6V clamping capability and 840mA peak pulse current rating in an SC-74 package. The MMQA20VT1 is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. The active equivalent MMQA20VT1G provides identical electrical performance with improved RoHS3 compliance and current availability.

Key Parameters

Parameter	Value
Voltage - Reverse Standoff (Typ)	15V (Max)
Voltage - Breakdown (Min)	19V
Voltage - Clamping (Max) @ Ipp	28.6V
Current - Peak Pulse (10/1000µs)	840mA (8/20µs)
Power - Peak Pulse	150W
Unidirectional Channels	4
Operating Temperature	-55°C ~ 150°C (TJ)
Mounting Type	Surface Mount
Package / Case	SC-74, SOT-457
Type	Zener
Applications	General Purpose

Substitute Part Grouping Explanation

Substitution for the MMQA20VT1 is determined by strict alignment of electrical and mechanical parameters within the TVS diode category. The primary substitution criterion is the reverse standoff voltage and clamping voltage range, which must remain within the specified operating window to ensure equivalent circuit protection. Secondary criteria include peak pulse current capability, package compatibility, and thermal operating range.

The MMQA20VT1G represents a direct equivalent with identical electrical specifications and improved product status (Active vs. Obsolete). The Nexperia BZA420A series (BZA420A,115; BZA420A,125; BZA420A,165) provides functional substitution with matching 20V reverse standoff and 28V clamping voltages, though these parts use a different package variant (6-TSOP vs. SC-74) and lower peak pulse power rating (19.6W vs. 150W). The BZA456A series (BZA456A,115; BZA456A,125; BZA456A,135; BZA456A,165) operates at significantly different voltage levels (5.6V standoff, 8V clamping) and is not suitable for direct substitution of the MMQA20VT1.

Parameter Comparison

Part Number	Manufacturer	Voltage - Reverse Standoff	Voltage - Clamping (Max) @ Ipp	Current - Peak Pulse	Power - Peak Pulse	Package	Product Status	RoHS Status
MMQA20VT1	onsemi	15V	28.6V	840mA (8/20µs)	150W	SC-74	Obsolete	RoHS non-compliant
MMQA20VT1G	onsemi	15V	28.6V	840mA (8/20µs)	150W	SC-74	Active	ROHS3 Compliant
BZA420A,115	Nexperia USA Inc.	20V	28V	Not specified	19.6W	6-TSOP	Active	ROHS3 Compliant
BZA420A,125	Nexperia USA Inc.	20V	28V	Not specified	19.6W	6-TSOP	Active	ROHS3 Compliant
BZA420A,135	Nexperia USA Inc.	20V	28V	Not specified	19.6W	6-TSOP	Active	ROHS3 Compliant
BZA420A,165	Nexperia USA Inc.	20V	28V	Not specified	19.6W	6-TSOP	Active	ROHS3 Compliant
BZA456A,115	Nexperia USA Inc.	5.6V	8V	3A (8/20µs)	24W	6-TSOP	Active	ROHS3 Compliant
BZA456A,125	Nexperia USA Inc.	5.6V	8V	3A (8/20µs)	24W	6-TSOP	Active	ROHS3 Compliant
BZA456A,135	Nexperia USA Inc.	5.6V	8V	3A (8/20µs)	24W	6-TSOP	Active	ROHS3 Compliant
BZA456A,165	Nexperia USA Inc.	5.6V	8V	3A (8/20µs)	24W	6-TSOP	Active	ROHS3 Compliant

Engineering Selection Recommendations

The MMQA20VT1G is the primary recommended substitute for the obsolete MMQA20VT1. Both parts share identical electrical specifications, thermal operating range, and package configuration. The MMQA20VT1G offers the advantage of Active product status with ROHS3 compliance, making it suitable for new designs and production environments with RoHS requirements.

The BZA420A series (all variants) provides functional substitution for applications where package migration is acceptable. These parts maintain equivalent clamping voltage (28V) and similar reverse standoff voltage (20V vs. 15V), though they operate at reduced peak pulse power (19.6W vs. 150W). Package change from SC-74 to 6-TSOP requires PCB layout modification. All BZA420A variants carry Active product status and ROHS3 compliance.

The BZA456A series is not suitable for direct substitution due to fundamentally different voltage ratings (5.6V standoff, 8V clamping). This series addresses different circuit protection requirements and cannot replace the MMQA20VT1 in 15V/28.6V protection applications.

Frequently Asked Questions (FAQ)

Q: Can MMQA20VT1G be used as a direct replacement for MMQA20VT1?

A: Yes. MMQA20VT1G provides identical electrical performance with matching reverse standoff voltage (15V), clamping voltage (28.6V), peak pulse current (840mA), and power rating (150W). Both use SC-74 packaging. The primary difference is product status (Active vs. Obsolete) and RoHS compliance (ROHS3 vs. non-compliant).

Q: What are the limitations of using BZA420A series as substitutes?

A: BZA420A parts differ in three key aspects: (1) Package change from SC-74 to 6-TSOP requires PCB redesign, (2) Peak pulse power reduced from 150W to 19.6W, limiting high-energy transient handling, and (3) Reverse standoff voltage increased from 15V to 20V, which may affect circuit triggering behavior in marginal conditions.

Q: Why are BZA456A parts listed but not recommended?

A: BZA456A parts operate at 5.6V reverse standoff and 8V clamping voltage, designed for low-voltage protection circuits. These specifications are incompatible with the MMQA20VT1's 15V/28.6V protection window and cannot provide equivalent overvoltage suppression for 15V standoff applications.

Q: Are all substitute parts RoHS compliant?

A: MMQA20VT1G and all BZA420A and BZA456A variants are ROHS3 compliant. The original MMQA20VT1 is RoHS non-compliant, making MMQA20VT1G the preferred choice for new designs subject to RoHS regulations.

Q: What is the thermal operating range for substitute parts?

A: MMQA20VT1G maintains the original -55°C to 150°C (TJ) range. BZA420A and BZA456A series extend the lower temperature limit to -65°C, providing wider thermal operating capability.

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