MMSZ5238B Equivalent & Substitute Parts

Part Overview

The MMSZ5238B is a Zener diode rated at 8.7 V nominal with 500 mW power dissipation in a surface mount SOD-123 package. Manufactured by onsemi, this component is classified as obsolete product status. Due to its obsolete designation, identifying equivalent and substitute parts from active manufacturers is essential for ongoing design support, production continuity, and long-term component availability in new applications.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	8.7	V
Tolerance	±5%	%
Power - Max	500	mW
Impedance (Max)	8	Ohms
Current - Reverse Leakage @ Vr	3	µA @ 6.5 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 MMSZ5238B is determined by strict equivalence across the following critical parameters:

Primary Substitution Criteria:

Voltage - Zener (Nom): 8.7 V
Tolerance: ±5%
Power - Max: 500 mW
Impedance (Max): 8 Ohms
Current - Reverse Leakage @ Vr: 3 µA @ 6.5 V
Voltage - Forward (Vf) (Max) @ If: 900 mV @ 10 mA
Operating Temperature: -55°C to 150°C minimum
Mounting Type: Surface Mount
Package / Case: SOD-123

Substitution Categories:

Direct Manufacturer Equivalents maintain all electrical and mechanical parameters identically to the main part. These parts are sourced from onsemi and alternative manufacturers with active product status.

Parametric Equivalents meet all electrical specifications but may include enhanced qualifications such as automotive-grade certification (AEC-Q101) or extended temperature ranges. These parts are functionally interchangeable in standard applications.

Similar Parts share the same nominal voltage and package but may differ in power rating, impedance, or reverse leakage characteristics. These parts are suitable only when application requirements permit deviation from the primary specifications.

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ohms)	Ir @ Vr (µA)	Vf @ If (mV)	Temp Range (°C)	Package	Status
MMSZ5238B	onsemi	8.7	±5%	500	8	3 @ 6.5V	900 @ 10mA	-55 to 150	SOD-123	Obsolete
MMSZ5238BT1G	onsemi	8.7	±5%	500	8	3 @ 6.5V	900 @ 10mA	-55 to 150	SOD-123	Active
SZMMSZ5238BT1G	onsemi	8.7	±5%	500	8	3 @ 6.5V	900 @ 10mA	-55 to 150	SOD-123	Active
MMSZ5238B-TP	Micro Commercial Co	8.7	±5%	500	8	3 @ 6.5V	—	-55 to 150	SOD-123	Active
MMSZ5238B-7-F	Diodes Incorporated	8.7	±5%	500	8	3 @ 6.5V	900 @ 10mA	-65 to 150	SOD-123	Active
CMHZ5238B TR PBFREE	Central Semiconductor Corp	8.7	±5%	500	8	3 @ 6.5V	900 @ 10mA	-65 to 150	SOD-123	Active
MMSZ4695-G3-18	Vishay General Semiconductor	8.7	±5%	500	—	1 @ 6.6V	—	-55 to 150	SOD-123	Active
MMSZ5238B_R1_00001	Panjit International Inc.	8.7	±5%	500	8	3 @ 6.5V	—	-55 to 150	SOD-123	Active
BZT52H-C9V1,115	Nexperia USA Inc.	9.1	±5%	375	10	0.5 @ 6V	900 @ 10mA	-65 to 150	SOD-123F	Active
CZRW5238B-G	Comchip Technology	8.7	±5%	350	8	3 @ 6.5V	900 @ 10mA	-65 to 150	SOD-123	Active
DDZ9V1BQ-7	Diodes Incorporated	9.1	±2.5%	500	8	0.1 @ 7V	900 @ 10mA	-65 to 150	SOD-123	Active

Engineering Selection Recommendations

Direct Equivalents for Immediate Substitution:

MMSZ5238BT1G (onsemi) and MMSZ5238B-TP (Micro Commercial Co) are direct electrical and mechanical equivalents with active product status. Both maintain identical specifications across all critical parameters and are suitable for direct replacement in existing designs without circuit modification.

Enhanced Specification Alternatives:

SZMMSZ5238BT1G (onsemi) provides automotive-grade qualification with AEC-Q101 certification while maintaining all electrical parameters. This part is appropriate for applications requiring automotive-level reliability and traceability.

MMSZ5238B-7-F (Diodes Incorporated) and CMHZ5238B TR PBFREE (Central Semiconductor Corp) extend the lower operating temperature limit to -65°C, providing enhanced performance in extreme cold environments while preserving all other specifications.

Parametric Alternatives with Minor Deviations:

MMSZ4695-G3-18 (Vishay) maintains the 8.7 V nominal voltage and 500 mW power rating with reduced reverse leakage (1 µA @ 6.6 V versus 3 µA @ 6.5 V), offering improved leakage characteristics for precision applications.

MMSZ5238B_R1_00001 (Panjit International Inc.) provides full electrical equivalence with active status and is available in high volume.

Similar Parts with Application-Dependent Suitability:

CZRW5238B-G (Comchip Technology) maintains 8.7 V nominal voltage but reduces power rating to 350 mW. This part is suitable only for applications where power dissipation does not exceed 350 mW.

BZT52H-C9V1,115 (Nexperia USA Inc.) and DDZ9V1BQ-7 (Diodes Incorporated) operate at 9.1 V nominal voltage with enhanced automotive qualification. These parts are suitable only when the higher voltage specification is acceptable to the circuit design.

Frequently Asked Questions (FAQ)

Q: Can MMSZ5238BT1G be used as a direct replacement for MMSZ5238B?

A: Yes. MMSZ5238BT1G maintains identical electrical specifications (8.7 V, 500 mW, ±5% tolerance) and mechanical packaging (SOD-123 surface mount). The primary difference is active product status and tape & reel packaging format. No circuit modification is required.

Q: What is the difference between MMSZ5238BT1G and SZMMSZ5238BT1G?

A: Both parts are manufactured by onsemi with identical electrical parameters. SZMMSZ5238BT1G includes automotive-grade qualification and AEC-Q101 certification, making it suitable for automotive applications requiring enhanced reliability documentation. Standard applications may use either part interchangeably.

Q: Is MMSZ5238B-7-F compatible with MMSZ5238B?

A: Yes, with extended capability. MMSZ5238B-7-F (Diodes Incorporated) maintains all electrical specifications but extends the lower operating temperature to -65°C compared to -55°C for the original part. This part is a suitable replacement for all applications and provides enhanced performance in cold environments.

Q: Can CZRW5238B-G replace MMSZ5238B in all applications?

A: No. CZRW5238B-G reduces the maximum power rating from 500 mW to 350 mW. This part is suitable only for applications where power dissipation remains below 350 mW. Verify application power requirements before substitution.

Q: What is the significance of the SOD-123F package used in BZT52H-C9V1,115?

A: SOD-123F is a variant of the SOD-123 package with different mechanical dimensions. BZT52H-C9V1,115 is not a direct mechanical substitute due to package differences. Additionally, its 9.1 V nominal voltage differs from the 8.7 V specification. This part is suitable only when both the higher voltage and different package footprint are acceptable.

Q: Are all substitute parts RoHS3 compliant?

A: All active substitute parts listed are RoHS3 compliant. The original MMSZ5238B does not specify RoHS status. All substitute parts maintain REACH Unaffected status and EAR99 export classification.

Q: Which substitute part offers the lowest reverse leakage current?

A: DDZ9V1BQ-7 (Diodes Incorporated) specifies 100 nA @ 7 V reverse leakage, the lowest among listed parts. However, this part operates at 9.1 V nominal voltage and is suitable only when the higher voltage specification is acceptable.

Q: Can MMSZ4695-G3-18 be used in place of MMSZ5238B?

A: Yes, with qualification. MMSZ4695-G3-18 maintains 8.7 V nominal voltage and 500 mW power rating with improved reverse leakage characteristics (1 µA @ 6.6 V). This part is suitable for applications where lower leakage is beneficial. Verify impedance requirements, as this parameter is not specified for MMSZ4695-G3-18.

Q: What packaging format should be selected for high-volume production?

A: All active substitute parts are available in tape & reel (TR) packaging suitable for automated assembly. MMSZ5238BT1G, SZMMSZ5238BT1G, MMSZ5238B-TP, MMSZ5238B-7-F, and MMSZ5238B_R1_00001 all support high-volume production requirements with standard reel configurations.

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