MMSZ5229B Zener Diode 4.3V 500mW SOD-123 Equivalent & Substitute Parts

Part Overview

The MMSZ5229B is a surface mount zener diode manufactured by onsemi, rated for 4.3 V nominal zener voltage with 500 mW maximum power dissipation in SOD-123 packaging. This component is classified as obsolete, necessitating identification of active equivalent and substitute parts for ongoing design requirements and production continuity. Equivalent parts maintain identical electrical and mechanical specifications, while substitute parts provide functional alternatives within acceptable parameter tolerances for zener diode applications.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	4.3	V
Tolerance	±5%	—
Power - Max	500	mW
Impedance (Max)	22	Ohms
Current - Reverse Leakage @ Vr	5	µA @ 1 V
Voltage - Forward (Vf) (Max) @ If	900	mV @ 10 mA
Operating Temperature	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	SOD-123	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the MMSZ5229B is determined by the following critical parameters: nominal zener voltage (4.3 V), tolerance (±5%), maximum power rating (500 mW), package type (SOD-123), and operating temperature range (-55°C to 150°C). Parts are grouped into three categories based on substitution relationship:

Direct Manufacturer Equivalents: Parts from onsemi with identical electrical specifications and SOD-123 packaging, differing only in product status (active vs. obsolete) or packaging format (tape & reel, cut tape, digi-reel).

Parametric Equivalents: Parts meeting all critical electrical parameters with automotive-grade qualification (AEC-Q101) and enhanced reliability certifications.

Cross-Manufacturer Alternatives: Parts from alternative manufacturers (Central Semiconductor Corp, Micro Commercial Co, Diodes Incorporated) meeting the same electrical and mechanical specifications within defined tolerance ranges.

Similar Parts: Components with minor parameter variations (tolerance ±7%, different impedance values, extended temperature ranges) suitable for applications where specification flexibility exists.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power Max	Zzt (Max)	Reverse Leakage	Vf (Max)	Temp Range	Product Status	Packaging
MMSZ5229B	onsemi	4.3 V	±5%	500 mW	22 Ω	5 µA @ 1 V	900 mV @ 10 mA	-55 to 150°C	Obsolete	SOD-123
MMSZ4687T1G	onsemi	4.3 V	±5%	500 mW	—	4 µA @ 2 V	900 mV @ 10 mA	-55 to 150°C	Active	Tape & Reel
MMSZ4V3T1G	onsemi	4.3 V	±5%	500 mW	90 Ω	3 µA @ 1 V	900 mV @ 10 mA	-55 to 150°C	Active	Tape & Reel
MMSZ5229BT1G	onsemi	4.3 V	±5%	500 mW	22 Ω	5 µA @ 1 V	900 mV @ 10 mA	-55 to 150°C	Active	Cut Tape & Digi-Reel
SZMMSZ4687T1G	onsemi	4.3 V	±5%	500 mW	—	4 µA @ 2 V	900 mV @ 10 mA	-55 to 150°C	Active	Cut Tape & Digi-Reel
SZMMSZ4V3T1G	onsemi	4.3 V	±5%	500 mW	90 Ω	3 µA @ 1 V	900 mV @ 10 mA	-55 to 150°C	Active	Tape & Reel
SZMMSZ5229BT1G	onsemi	4.3 V	±5%	500 mW	22 Ω	5 µA @ 1 V	900 mV @ 10 mA	-55 to 150°C	Active	Tape & Reel
CMHZ4687 TR PBFREE	Central Semiconductor Corp	4.3 V	±5%	500 mW	—	4 µA @ 2 V	1.5 V @ 100 mA	-65 to 150°C	Active	Tape & Reel
MMSZ5229B-TP	Micro Commercial Co	4.3 V	±5%	500 mW	22 Ω	5 µA @ 1 V	900 mV @ 10 mA	-55 to 150°C	Active	Tape & Reel
MMSZ5229B-7-F	Diodes Incorporated	4.3 V	±5%	500 mW	22 Ω	5 µA @ 1 V	900 mV @ 10 mA	-65 to 150°C	Active	Tape & Reel
BZT52C4V3-7-F	Diodes Incorporated	4.3 V	±7%	500 mW	90 Ω	3 µA @ 1 V	900 mV @ 10 mA	-65 to 150°C	Active	Tape & Reel

Engineering Selection Recommendations

Primary Recommendation - Direct onsemi Equivalent: MMSZ5229BT1G is the direct active equivalent from onsemi, maintaining identical electrical specifications (4.3 V, ±5% tolerance, 500 mW, 22 Ω impedance) and operating temperature range. This part is RoHS3 compliant and available in cut tape and digi-reel packaging formats. Selection of this part eliminates any specification variance from the original MMSZ5229B.

Automotive-Grade Alternative: SZMMSZ5229BT1G provides identical electrical specifications with automotive-grade qualification (AEC-Q101) and RoHS3 compliance. This part is suitable for applications requiring automotive reliability standards and extended supply chain assurance.

Cross-Manufacturer Option: MMSZ5229B-7-F from Diodes Incorporated provides identical electrical specifications with extended operating temperature range (-65°C to 150°C) and RoHS3 compliance. This part is suitable for applications requiring lower minimum operating temperature performance.

Alternative Impedance Selection: MMSZ4V3T1G and SZMMSZ4V3T1G offer 90 Ω impedance (versus 22 Ω) with lower reverse leakage (3 µA @ 1 V). These parts are suitable for applications where higher impedance characteristics are acceptable or beneficial.

Tolerance Consideration: BZT52C4V3-7-F from Diodes Incorporated provides ±7% tolerance (versus ±5%) with 90 Ω impedance. This part is suitable only for applications where ±7% zener voltage tolerance meets design requirements.

Frequently Asked Questions (FAQ)

Q: Can MMSZ4687T1G be used as a direct replacement for MMSZ5229B? A: MMSZ4687T1G meets all critical electrical specifications (4.3 V, ±5%, 500 mW) and operates within the same temperature range. The primary difference is reverse leakage specification (4 µA @ 2 V versus 5 µA @ 1 V), which represents improved leakage performance. This part is functionally equivalent for standard applications.

Q: What is the difference between MMSZ5229BT1G and SZMMSZ5229BT1G? A: Both parts are electrically identical with 4.3 V nominal voltage, ±5% tolerance, and 500 mW power rating. SZMMSZ5229BT1G carries automotive-grade qualification (AEC-Q101) and is designated for automotive applications. Selection depends on application requirements and supply chain preferences.

Q: Why do some substitute parts have different impedance values (22 Ω vs. 90 Ω)? A: Impedance (Zzt) is a dynamic parameter affecting transient response characteristics. Parts with 22 Ω impedance (MMSZ5229BT1G, SZMMSZ5229BT1G) match the original specification exactly. Parts with 90 Ω impedance (MMSZ4V3T1G, SZMMSZ4V3T1G) provide alternative impedance characteristics suitable for different circuit requirements. Selection should be based on circuit design specifications.

Q: Is BZT52C4V3-7-F suitable as a replacement? A: BZT52C4V3-7-F meets the 4.3 V nominal voltage and 500 mW power requirements. However, it specifies ±7% tolerance versus the original ±5% tolerance, and 90 Ω impedance versus 22 Ω. This part is suitable only if the application design permits ±7% voltage tolerance and higher impedance characteristics.

Q: What packaging formats are available for equivalent parts? A: Equivalent parts are available in three packaging formats: Tape & Reel (TR), Cut Tape (CT) & Digi-Reel, and bulk packaging. Selection depends on production volume and assembly equipment compatibility. All formats maintain identical electrical specifications and SOD-123 case dimensions.

Q: Are all substitute parts RoHS3 compliant? A: All active substitute parts listed are RoHS3 compliant. The original MMSZ5229B (obsolete) does not specify RoHS status. All active alternatives meet current environmental compliance requirements.

Q: Can I use CMHZ4687 TR PBFREE from Central Semiconductor Corp? A: CMHZ4687 TR PBFREE meets the 4.3 V nominal voltage, ±5% tolerance, and 500 mW power specifications. The forward voltage specification differs (1.5 V @ 100 mA versus 900 mV @ 10 mA), reflecting different measurement conditions. This part is functionally equivalent and RoHS3 compliant. Extended temperature range (-65°C to 150°C) provides additional margin.

Q: What is the significance of the "SZ" prefix in SZMMSZ part numbers? A: The "SZ" prefix designates automotive-grade qualification with AEC-Q101 certification. These parts are suitable for automotive applications requiring enhanced reliability and traceability standards.

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