MM5Z12V Equivalent & Substitute Parts

Part Overview

The MM5Z12V is a Zener diode manufactured by onsemi, rated at 12 V nominal with 200 mW power dissipation in a surface mount SOD-523F package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The MM5Z12V serves voltage regulation and protection functions in electronic circuits requiring 12 V Zener reference characteristics with compact surface mount packaging.

Key Parameters

Parameter	Value
Voltage - Zener (Nom)	12 V
Power - Max	200 mW
Tolerance	±5%
Impedance (Max)	25 Ohms
Current - Reverse Leakage @ Vr	100 nA @ 8 V
Operating Temperature	-55°C ~ 150°C
Mounting Type	Surface Mount
Package / Case	SC-79, SOD-523F
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the MM5Z12V is determined by the following critical parameters:

Voltage Matching: All substitute parts maintain the 12 V nominal Zener voltage specification, ensuring functional equivalence in voltage regulation and protection circuits.

Package Compatibility: Substitutes are grouped by package type. The MM5Z12V uses SOD-523F packaging. Direct substitutes in SOD-523 packaging (MM5Z12VT1G, BZT52C12T-TP, BZX584C12_R1_00001, BZX585 series) are pin-compatible for most applications. BZX84J-B12,115 uses SOD-323F packaging and requires PCB layout modification.

Power Dissipation: The MM5Z12V is rated at 200 mW. Substitutes with equal or higher power ratings (MM5Z12VT1G at 500 mW, BZX585 series at 300 mW, BZX84J-B12,115 at 550 mW) are directly substitutable. BZT52C12T-TP at 100 mW is suitable only for applications with reduced power requirements.

Impedance and Leakage: The MM5Z12V specifies 25 Ohms maximum impedance and 100 nA reverse leakage at 8 V. BZX585 series parts offer superior impedance performance at 10 Ohms maximum, providing tighter voltage regulation. BZX585-C12,115 specifies 100 µA reverse leakage, which differs from the 100 nA specification.

Temperature Range: The MM5Z12V operates from -55°C to 150°C. Substitutes with extended ranges (-65°C to 150°C) provide broader operational capability without functional compromise.

Product Status and Compliance: Active status substitutes ensure ongoing availability and support. Automotive-grade parts (BZX585 series, BZX84J-B12,115) include AEC-Q100 or AEC-Q101 qualification, suitable for applications requiring automotive reliability standards.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Power (Max)	Tolerance	Impedance (Max)	Leakage @ 8V	Temp Range	Package	Status
MM5Z12V	onsemi	12 V	200 mW	±5%	25 Ω	100 nA	-55°C ~ 150°C	SOD-523F	Obsolete
MM5Z12VT1G	onsemi	12 V	500 mW	±5.4%	25 Ω	100 nA	-65°C ~ 150°C	SOD-523	Active
BZT52C12T-TP	Micro Commercial Co	12 V	100 mW	±5%	25 Ω	100 nA	-65°C ~ 150°C	SOD-523	Active
BZX584C12_R1_00001	Panjit International Inc.	12 V	200 mW	±5%	25 Ω	100 nA	-55°C ~ 150°C	SOD-523	Active
BZX585-B12,115	Nexperia USA Inc.	12 V	300 mW	±2%	10 Ω	100 nA	-65°C ~ 150°C	SOD-523	Active
BZX585-B12,135	Nexperia USA Inc.	12 V	300 mW	±2%	10 Ω	100 nA	-65°C ~ 150°C	SOD-523	Active
BZX585-C12,115	Nexperia USA Inc.	12 V	300 mW	±5%	10 Ω	100 µA	-65°C ~ 150°C	SOD-523	Active
BZX585-C12,135	Nexperia USA Inc.	12 V	300 mW	±5%	10 Ω	100 µA	-65°C ~ 150°C	SOD-523	Active
BZX84J-B12,115	Nexperia USA Inc.	12 V	550 mW	±2%	10 Ω	100 nA	-65°C ~ 150°C	SOD-323F	Active

Engineering Selection Recommendations

Direct Replacement (Same Package, Active Status):

MM5Z12VT1G is the primary direct replacement from onsemi. It maintains the same manufacturer lineage, uses compatible SOD-523 packaging, and provides enhanced specifications with 500 mW power rating and extended temperature range (-65°C to 150°C). This part is active and recommended for new designs requiring onsemi sourcing continuity.

BZX584C12_R1_00001 from Panjit International Inc. matches the MM5Z12V specifications exactly: 12 V, 200 mW, ±5% tolerance, 25 Ω impedance, and -55°C to 150°C operating range. This part is active and suitable for direct substitution in existing designs.

Enhanced Performance Alternatives (SOD-523 Package, Active Status):

BZX585-B12,115 and BZX585-B12,135 from Nexperia USA Inc. offer improved impedance (10 Ω versus 25 Ω) and tighter tolerance (±2% versus ±5%), with 300 mW power rating. Both include AEC-Q100 automotive qualification and extended temperature range. These parts are suitable for applications requiring superior voltage regulation stability.

BZX585-C12,115 and BZX585-C12,135 maintain ±5% tolerance matching the MM5Z12V while providing 300 mW power and 10 Ω impedance. Both include AEC-Q100 automotive qualification. Note: reverse leakage is specified at 100 µA rather than 100 nA, which may affect applications with strict leakage requirements.

Lower Power Applications (SOD-523 Package, Active Status):

BZT52C12T-TP from Micro Commercial Co is suitable only for applications where power dissipation does not exceed 100 mW. This part maintains 12 V, ±5% tolerance, and 25 Ω impedance with extended temperature range (-65°C to 150°C).

Alternative Package (SOD-323F, Active Status):

BZX84J-B12,115 from Nexperia USA Inc. uses SOD-323F packaging, requiring PCB layout modification. This part offers 550 mW power, ±2% tolerance, 10 Ω impedance, and AEC-Q101 automotive qualification. Selection of this part is appropriate only when SOD-323F package footprint is available or when higher power dissipation is required.

Frequently Asked Questions (FAQ)

Q: Can MM5Z12VT1G directly replace MM5Z12V without PCB modification?

A: MM5Z12VT1G uses SOD-523 packaging while MM5Z12V uses SOD-523F. Both are surface mount packages with identical pin configurations and footprints. Direct PCB substitution is possible without layout modification.

Q: What is the difference between BZX585-B12,115 and BZX585-C12,115?

A: Both parts are rated at 12 V, 300 mW, and use SOD-523 packaging. The primary difference is tolerance: BZX585-B12,115 specifies ±2% tolerance while BZX585-C12,115 specifies ±5% tolerance. BZX585-B12,115 is preferred for applications requiring tighter voltage regulation. Additionally, BZX585-C12,115 specifies 100 µA reverse leakage compared to 100 nA for BZX585-B12,115.

Q: Is BZX84J-B12,115 compatible with MM5Z12V circuit designs?

A: BZX84J-B12,115 provides equivalent 12 V Zener voltage and superior electrical performance (550 mW, ±2% tolerance, 10 Ω impedance). However, it uses SOD-323F packaging instead of SOD-523F, requiring PCB footprint modification. Electrical substitution is valid; physical substitution requires layout redesign.

Q: Why does BZT52C12T-TP have lower power rating than MM5Z12V?

A: BZT52C12T-TP is rated at 100 mW compared to MM5Z12V at 200 mW. This part is suitable only for low-power applications. For circuits requiring 200 mW or higher dissipation, use MM5Z12VT1G, BZX584C12_R1_00001, or BZX585 series parts.

Q: What does AEC-Q100 qualification mean for automotive applications?

A: AEC-Q100 is an automotive electronics qualification standard. Parts with this certification (BZX585 series, BZX84J-B12,115) meet automotive reliability and quality requirements. These parts are suitable for automotive and industrial applications requiring enhanced reliability standards.

Q: Can I use BZX585-C12,115 in circuits sensitive to reverse leakage current?

A: BZX585-C12,115 specifies 100 µA reverse leakage at 8 V, which is significantly higher than MM5Z12V at 100 nA. For applications with strict leakage requirements, use BZX585-B12,115 (100 nA leakage) or BZX584C12_R1_00001 (100 nA leakage) instead.

Q: What is the advantage of MM5Z12VT1G over BZX584C12_R1_00001?

A: MM5Z12VT1G offers 500 mW power rating versus BZX584C12_R1_00001 at 200 mW, providing greater thermal margin. MM5Z12VT1G also extends the operating temperature range to -65°C. BZX584C12_R1_00001 provides exact specification matching to MM5Z12V. Selection depends on whether enhanced power handling or specification matching is prioritized.

Q: Are all substitute parts RoHS3 compliant?

A: All active substitute parts listed (MM5Z12VT1G, BZT52C12T-TP, BZX584C12_R1_00001, BZX585 series, BZX84J-B12,115) are RoHS3 compliant. The obsolete MM5Z12V does not specify RoHS status.

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