MMSZ5231B Zener Diode 5.1V 500mW SOD-123 Equivalent & Substitute Parts

Part Overview

The MMSZ5231B is a surface mount zener diode rated at 5.1 V nominal with 500 mW power dissipation in SOD-123 packaging, manufactured by onsemi. This component is classified as obsolete product status. Identification of equivalent and substitute parts is necessary to support ongoing design requirements, procurement continuity, and system maintenance where the original part number is no longer actively produced.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	5.1	V
Tolerance	±5%	—
Power - Max	500	mW
Impedance (Max)	17	Ohms
Current - Reverse Leakage @ Vr	5	µA @ 2 V
Voltage - Forward (Vf) (Max) @ If	900	mV @ 10 mA
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	SOD-123	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the MMSZ5231B is determined by electrical and mechanical parameter alignment within the zener diode category. The critical parameters for substitution are:

Electrical Parameters:

Voltage - Zener (Nom): 5.1 V
Tolerance: ±5% or tighter
Power - Max: 500 mW
Voltage - Forward (Vf) (Max) @ If: 900 mV @ 10 mA
Operating Temperature Range: -55°C to 150°C

Mechanical Parameters:

Mounting Type: Surface Mount
Package / Case: SOD-123
Supplier Device Package: SOD-123

Substitute parts are grouped into three categories:

Direct Manufacturer Substitutes: Parts with identical electrical specifications and standard commercial grade qualification.

Parametric Equivalents: Parts with matching core electrical parameters but variations in impedance tolerance or voltage tolerance that remain within acceptable operating margins.

Automotive Grade Alternatives: Parts meeting the same electrical specifications with AEC-Q101 automotive qualification for applications requiring enhanced reliability standards.

Parameter Comparison

Part Number	Manufacturer	Product Status	Vz (Nom)	Tolerance	Power Max	Zzt (Max)	Vf (Max) @ If	Temp Range	Package	Grade	RoHS Status
MMSZ5231B	onsemi	Obsolete	5.1 V	±5%	500 mW	17 Ω	900 mV @ 10 mA	-55 to 150°C	SOD-123	Commercial	—
MMSZ4689ET1G	onsemi	Active	5.1 V	±5%	500 mW	—	900 mV @ 10 mA	-55 to 150°C	SOD-123	Commercial	ROHS3 Compliant
MMSZ4689T3G	onsemi	Active	5.1 V	±5%	500 mW	—	900 mV @ 10 mA	-55 to 150°C	SOD-123	Commercial	ROHS3 Compliant
MMSZ5231BT1G	onsemi	Active	5.1 V	±5%	500 mW	17 Ω	900 mV @ 10 mA	-55 to 150°C	SOD-123	Commercial	ROHS3 Compliant
MMSZ5V1T1G	onsemi	Active	5.1 V	±5%	500 mW	60 Ω	900 mV @ 10 mA	-55 to 150°C	SOD-123	Commercial	ROHS3 Compliant
SZMMSZ4689ET1G	onsemi	Active	5.1 V	±5%	500 mW	—	900 mV @ 10 mA	-55 to 150°C	SOD-123	Automotive	ROHS3 Compliant
SZMMSZ4689T1G	onsemi	Active	5.1 V	±5%	500 mW	—	900 mV @ 10 mA	-55 to 150°C	SOD-123	Automotive	ROHS3 Compliant
SZMMSZ5V1T1G	onsemi	Active	5.1 V	±5%	500 mW	60 Ω	900 mV @ 10 mA	-55 to 150°C	SOD-123	Automotive	ROHS3 Compliant
MMSZ5231BT3G	onsemi	Active	5.1 V	±5%	500 mW	17 Ω	900 mV @ 10 mA	-55 to 150°C	SOD-123	Commercial	ROHS3 Compliant
MMSZ5231CT1G	onsemi	Active	5.1 V	±2%	500 mW	17 Ω	900 mV @ 10 mA	-55 to 150°C	SOD-123	Commercial	ROHS3 Compliant
SZMMSZ5231BT1G	onsemi	Active	5.1 V	±5%	500 mW	17 Ω	900 mV @ 10 mA	-55 to 150°C	SOD-123	Automotive	ROHS3 Compliant

Engineering Selection Recommendations

For Commercial Applications (Non-Automotive):

MMSZ5231BT1G is the primary direct replacement for MMSZ5231B. Both parts share identical electrical specifications including 17 Ohm maximum impedance and 5 µA reverse leakage current at 2 V. MMSZ5231BT1G carries active product status and ROHS3 compliance, providing design continuity with modern supply chain support.

MMSZ4689ET1G and MMSZ4689T3G are functionally equivalent alternatives with matching 5.1 V nominal voltage and 500 mW power rating. These parts differ in reverse leakage specification (10 µA @ 3 V versus 5 µA @ 2 V) and lack impedance specification, making them suitable for applications where impedance tolerance is not a critical design parameter.

MMSZ5V1T1G provides equivalent electrical performance with higher impedance tolerance (60 Ohm maximum). This part is appropriate for circuits where impedance variation does not affect circuit performance.

MMSZ5231CT1G offers tighter voltage tolerance (±2% versus ±5%), providing enhanced voltage regulation accuracy for precision applications requiring stricter zener voltage control.

For Automotive Applications (AEC-Q101 Qualified):

SZMMSZ5231BT1G is the automotive-grade equivalent with identical electrical specifications to MMSZ5231B, including 17 Ohm impedance and 5 µA reverse leakage. This part is qualified to AEC-Q101 automotive standards and carries active product status.

SZMMSZ4689ET1G and SZMMSZ4689T1G provide automotive-qualified alternatives with matching 5.1 V nominal voltage and 500 mW power rating, suitable for automotive applications where impedance specification is not required.

SZMMSZ5V1T1G offers automotive qualification with higher impedance tolerance (60 Ohm maximum) for automotive circuits where impedance variation is acceptable.

All substitute parts maintain the -55°C to 150°C operating temperature range and SOD-123 surface mount package, ensuring mechanical and thermal compatibility with the original design.

Frequently Asked Questions (FAQ)

Q: Can MMSZ4689ET1G directly replace MMSZ5231B in all applications?

A: MMSZ4689ET1G matches the core electrical specifications of 5.1 V nominal voltage, ±5% tolerance, and 500 mW power rating. However, it does not specify impedance (Zzt) while MMSZ5231B specifies 17 Ohm maximum impedance. Applications requiring controlled impedance characteristics should use MMSZ5231BT1G instead.

Q: What is the difference between MMSZ5231BT1G and MMSZ5V1T1G?

A: Both parts provide 5.1 V nominal zener voltage with ±5% tolerance and 500 mW power rating in SOD-123 packaging. The primary difference is impedance specification: MMSZ5231BT1G specifies 17 Ohm maximum impedance, while MMSZ5V1T1G specifies 60 Ohm maximum impedance. MMSZ5231BT1G is the preferred substitute for MMSZ5231B due to matching impedance characteristics.

Q: Are automotive-grade parts (SZMMSZ series) compatible with commercial applications?

A: Yes. Automotive-grade parts meeting AEC-Q101 qualification exceed commercial-grade requirements and are fully compatible with commercial applications. SZMMSZ5231BT1G can be used in any application where MMSZ5231B was specified, with the benefit of enhanced reliability qualification.

Q: What is the significance of the "T1G" and "T3G" suffixes in part numbers?

A: The suffix indicates packaging format. "T1G" denotes Cut Tape (CT) & Digi-Reel® packaging, while "T3G" denotes Tape & Reel (TR) packaging. Both formats contain identical components; the difference is in supply reel configuration. Selection depends on assembly equipment compatibility and procurement volume requirements.

Q: Why does MMSZ5231CT1G have ±2% tolerance instead of ±5%?

A: MMSZ5231CT1G is a parametric equivalent with tighter voltage tolerance specification. The ±2% tolerance provides enhanced voltage regulation accuracy compared to the ±5% tolerance of MMSZ5231B. This part is suitable for precision voltage reference applications requiring stricter zener voltage control.

Q: Is MMSZ5231B still available for procurement?

A: MMSZ5231B is classified as obsolete product status. Active substitute parts including MMSZ5231BT1G, MMSZ4689ET1G, and MMSZ4689T3G are available for new designs and ongoing procurement requirements.

Q: What is the reverse leakage current difference between substitute parts?

A: MMSZ5231B and MMSZ5231BT1G specify 5 µA reverse leakage at 2 V. MMSZ4689ET1G, MMSZ4689T3G, SZMMSZ4689ET1G, and SZMMSZ4689T1G specify 10 µA reverse leakage at 3 V. MMSZ5V1T1G and SZMMSZ5V1T1G specify 2 µA reverse leakage at 2 V. Applications sensitive to leakage current should select parts with specifications matching the original design requirement.

Q: Can I use MMSZ5231CT1G as a drop-in replacement for MMSZ5231B?

A: MMSZ5231CT1G is mechanically and electrically compatible with MMSZ5231B in SOD-123 packaging. The tighter ±2% voltage tolerance of MMSZ5231CT1G is a superset of the ±5% tolerance requirement, making it a valid substitute. However, the tighter tolerance may affect cost and availability; use only if precision voltage regulation is required.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message