MMBZ5252B Equivalent & Substitute Parts

Part Overview

The MMBZ5252B is a 24 V Zener diode rated at 350 mW in a surface mount SOT-23-3 package, manufactured by onsemi. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The MMBZ5252B serves voltage regulation and protection functions in electronic circuits requiring precise 24 V reference voltage with moderate power dissipation capability.

Key Parameters

Parameter	Value
Voltage - Zener (Nom)	24 V
Power - Max	350 mW
Tolerance	±5%
Impedance (Max)	33 Ohms
Current - Reverse Leakage @ Vr	100 nA @ 18 V
Voltage - Forward (Vf) (Max) @ If	900 mV @ 10 mA
Operating Temperature	-55°C ~ 150°C
Mounting Type	Surface Mount
Package / Case	TO-236-3, SC-59, SOT-23-3

Substitute Part Grouping Explanation

Substitution of the MMBZ5252B is determined by the following critical parameters:

Electrical Compatibility Requirements:

Zener voltage: 24 V nominal
Power dissipation: minimum 350 mW (or lower if circuit design permits)
Tolerance: ±5% or tighter
Impedance: 33 Ohms or lower
Reverse leakage: 100 nA @ 18 V or lower
Forward voltage: 900 mV @ 10 mA maximum
Operating temperature range: -55°C to 150°C minimum

Mechanical Compatibility Requirements:

Package: SOT-23-3 (TO-236-3, SC-59)
Mounting type: Surface Mount

Substitute parts are grouped into three categories based on their relationship to the main part specifications:

Direct Equivalents: Parts meeting all electrical parameters and maintaining 350 mW power rating with identical tolerance and impedance characteristics.

Similar Substitutes: Parts with reduced power ratings (225 mW) or modified impedance specifications that maintain core voltage regulation function within the same package.

Alternative Manufacturers: Parts from different manufacturers meeting equivalent electrical and mechanical specifications.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Power (Max)	Tolerance	Zzt (Max)	Vf (Max) @ If	Temp Range	Status
MMBZ5252B	onsemi	24 V	350 mW	±5%	33 Ohms	900 mV @ 10 mA	-55°C ~ 150°C	Obsolete
BZX84C24LT1G	onsemi	24 V	225 mW	±6%	70 Ohms	900 mV @ 10 mA	-65°C ~ 150°C	Active
MMBZ5252BLT1G	onsemi	24 V	225 mW	±5%	33 Ohms	900 mV @ 10 mA	-65°C ~ 150°C	Active
SZMMBZ5252BLT1G	onsemi	24 V	225 mW	±5%	33 Ohms	900 mV @ 10 mA	-65°C ~ 150°C	Active
CMPZ5252B BK PBFREE	Central Semiconductor Corp	24 V	350 mW	±5%	33 Ohms	900 mV @ 10 mA	-65°C ~ 150°C	Active
CMPZ5252B TR PBFREE	Central Semiconductor Corp	24 V	350 mW	±5%	33 Ohms	900 mV @ 10 mA	-65°C ~ 150°C	Active
MMBZ5252B-7-F	Diodes Incorporated	24 V	350 mW	±5%	33 Ohms	900 mV @ 10 mA	-65°C ~ 150°C	Active
MMBZ5252BQ-7-F	Diodes Incorporated	24 V	350 mW	±5%	33 Ohms	900 mV @ 10 mA	-65°C ~ 150°C	Active
BZX84B24-7-F	Diodes Incorporated	24 V	300 mW	±2%	70 Ohms	900 mV @ 10 mA	-65°C ~ 150°C	Active
BZX84B24-TP	Micro Commercial Co	24 V	350 mW	±2%	70 Ohms	900 mV @ 10 mA	-55°C ~ 150°C	Active
BZX84C24 TR	Central Semiconductor Corp	24 V	350 mW	±5%	70 Ohms	900 mV @ 10 mA	-65°C ~ 150°C	Active

Engineering Selection Recommendations

Direct Replacement (Preferred):

The MMBZ5252B-7-F (Diodes Incorporated) and MMBZ5252BQ-7-F (Diodes Incorporated) provide direct electrical and mechanical equivalence with active product status. Both maintain 350 mW power rating, ±5% tolerance, and 33 Ohms impedance. The MMBZ5252BQ-7-F includes AEC-Q101 automotive qualification, suitable for applications requiring automotive-grade components.

The CMPZ5252B BK PBFREE and CMPZ5252B TR PBFREE (Central Semiconductor Corp) offer equivalent specifications with active status and RoHS3 compliance. These parts maintain identical electrical parameters and are available in bulk and tape & reel packaging options.

Secondary Substitutes (Power-Reduced Applications):

The MMBZ5252BLT1G (onsemi) and SZMMBZ5252BLT1G (onsemi) reduce power dissipation to 225 mW while maintaining ±5% tolerance and 33 Ohms impedance. The SZMMBZ5252BLT1G includes AEC-Q101 automotive qualification. These parts are suitable for applications where circuit design permits lower power dissipation.

Alternative Impedance Designs:

The BZX84C24LT1G (onsemi) and BZX84C24 TR (Central Semiconductor Corp) feature 70 Ohms impedance with 225 mW and 350 mW power ratings respectively. These parts maintain 24 V nominal voltage and are suitable for applications tolerating higher impedance characteristics.

The BZX84B24-7-F (Diodes Incorporated) and BZX84B24-TP (Micro Commercial Co) provide ±2% tolerance with 70 Ohms impedance. The BZX84B24-TP maintains 350 mW power rating and -55°C to 150°C temperature range matching the original part.

Compliance Considerations:

All recommended substitutes maintain RoHS3 compliance and REACH unaffected status. All parts are classified under ECCN EAR99 and HTSUS 8541.10.0050. Moisture sensitivity level is 1 (Unlimited) for all listed parts.

Frequently Asked Questions (FAQ)

Q: Can MMBZ5252BLT1G replace MMBZ5252B in all applications?

A: MMBZ5252BLT1G is electrically compatible for applications where 225 mW power dissipation is sufficient. The original MMBZ5252B is rated at 350 mW. Circuit design must accommodate the reduced power rating. Electrical parameters including voltage, tolerance, and impedance are equivalent.

Q: What is the difference between MMBZ5252B-7-F and MMBZ5252BQ-7-F?

A: Both parts are manufactured by Diodes Incorporated with identical electrical specifications (24 V, 350 mW, ±5%, 33 Ohms). The MMBZ5252BQ-7-F includes AEC-Q101 automotive qualification and automotive-grade designation. Select MMBZ5252BQ-7-F for automotive applications requiring qualification documentation.

Q: Why do some substitutes have higher impedance (70 Ohms vs 33 Ohms)?

A: Impedance is a characteristic of the diode's internal structure and manufacturing process. Higher impedance (70 Ohms) affects dynamic response and voltage regulation characteristics. Parts with 70 Ohms impedance are suitable for applications tolerating these characteristics. For applications requiring 33 Ohms impedance, select MMBZ5252B-7-F, MMBZ5252BQ-7-F, CMPZ5252B variants, or onsemi MMBZ5252BLT1G.

Q: Are all substitutes available in SOT-23-3 package?

A: All listed substitutes are available in SOT-23-3 package (TO-236-3, SC-59). Packaging options vary by part number and supplier. CMPZ5252B variants are available in bulk and tape & reel configurations. Verify specific packaging availability with supplier documentation.

Q: What is the temperature range difference between MMBZ5252B and its substitutes?

A: The original MMBZ5252B operates from -55°C to 150°C. Most active substitutes extend the lower temperature limit to -65°C, providing wider operating range. The BZX84B24-TP maintains -55°C to 150°C matching the original specification. Select based on application temperature requirements.

Q: Can BZX84B24-TP replace MMBZ5252B despite ±2% tolerance?

A: BZX84B24-TP is electrically compatible with tighter ±2% tolerance, 350 mW power rating, and 900 mV forward voltage. The 70 Ohms impedance differs from the original 33 Ohms. This part is suitable for applications where tighter tolerance is beneficial and impedance characteristics are acceptable.

Q: What does RoHS3 compliance mean for these parts?

A: RoHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting lead and other hazardous materials. All active substitutes listed are RoHS3 compliant. The original MMBZ5252B does not specify RoHS status due to obsolete classification.

Q: Is SZMMBZ5252BLT1G suitable for automotive applications?

A: Yes. SZMMBZ5252BLT1G includes AEC-Q101 automotive qualification and automotive-grade designation. This part maintains 24 V nominal voltage, ±5% tolerance, 33 Ohms impedance, and 225 mW power rating. Select this part for automotive designs requiring qualified components.

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