MMSZ5239B-7 Equivalent & Substitute Parts

Part Overview

The MMSZ5239B-7 is a Zener diode rated at 9.1 V nominal with 500 mW power dissipation in a surface mount SOD-123 package. Manufactured by Diodes Incorporated, this component is classified as discontinued at DiGi Electronics. Identification of equivalent and substitute parts is necessary due to product discontinuation and the need for sourcing alternatives with compatible electrical and mechanical specifications for ongoing production and repair applications.

Key Parameters

Parameter	Value
Voltage - Zener (Nom) (Vz)	9.1 V
Tolerance	±5%
Power - Max	500 mW
Impedance (Max) (Zzt)	10 Ohms
Current - Reverse Leakage @ Vr	3 µA @ 7 V
Voltage - Forward (Vf) (Max) @ If	900 mV @ 10 mA
Operating Temperature	-65°C ~ 150°C
Mounting Type	Surface Mount
Package / Case	SOD-123

Substitute Part Grouping Explanation

Substitution of the MMSZ5239B-7 is determined by the following critical parameters:

Primary Substitution Criteria:

Voltage - Zener (Nom): 9.1 V
Power - Max: 500 mW (or higher)
Package / Case: SOD-123 or SOD-123F
Mounting Type: Surface Mount
Tolerance: ±5% (or tighter)

Secondary Compatibility Factors:

Operating Temperature Range: Minimum -55°C to 150°C
Impedance (Max): 10 Ohms or lower
Current - Reverse Leakage: Specification dependent on application requirements
Voltage - Forward (Vf): 900 mV @ 10 mA or lower

Substitute parts are grouped into two categories: Direct Parametric Equivalents (matching all primary specifications) and Functional Alternatives (meeting core electrical requirements with minor parameter variations acceptable for most applications).

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ohms)	Ir @ Vr	Vf @ If	Temp Range (°C)	Package	Status
MMSZ5239B-7	Diodes Incorporated	9.1	±5%	500	10	3 µA @ 7 V	900 mV @ 10 mA	-65 to 150	SOD-123	Discontinued
MMSZ5239B-7-F	Diodes Incorporated	9.1	±5%	500	10	3 µA @ 7 V	900 mV @ 10 mA	-65 to 150	SOD-123	Active
MMSZ4696-TP	Micro Commercial Co	9.1	±5%	500	—	10 µA @ 6.9 V	950 mV @ 10 mA	-55 to 150	SOD-123	Active
BZT52C9V1-G3-18	Vishay General Semiconductor - Diodes Division	9.1	±5%	410	10	100 nA @ 7 V	—	-55 to 150	SOD-123	Active
BZT52H-C9V1,115	Nexperia USA Inc.	9.1	±5%	375	10	500 nA @ 6 V	900 mV @ 10 mA	-65 to 150	SOD-123F	Active
MMSZ4696-E3-08	Vishay General Semiconductor - Diodes Division	9.1	±5%	500	—	1 µA @ 6.9 V	—	-55 to 150	SOD-123	Active
MMSZ5239B-TP	Micro Commercial Co	9.1	±5%	500	10	3 µA @ 7 V	900 mV @ 10 mA	-55 to 150	SOD-123	Active
MMSZ5239BT1G	onsemi	9.1	±5%	500	10	3 µA @ 7 V	900 mV @ 10 mA	-55 to 150	SOD-123	Active
NZH9V1B,115	NXP Semiconductors	9.1	±2%	500	8	500 nA @ 6 V	900 mV @ 10 mA	-55 to 150	SOD-123F	Active
SZMMSZ4696T1G	onsemi	9.1	±5%	500	—	1 µA @ 6.9 V	900 mV @ 10 mA	-55 to 150	SOD-123	Active
SZMMSZ5239BT1G	onsemi	9.1	±5%	500	10	3 µA @ 7 V	900 mV @ 10 mA	-55 to 150	SOD-123	Active

Engineering Selection Recommendations

Direct Parametric Equivalent (Recommended Primary Substitute):

The MMSZ5239B-7-F from Diodes Incorporated is the direct parametric equivalent. This part maintains identical electrical specifications to the original MMSZ5239B-7, including 9.1 V nominal voltage, 500 mW power rating, 10 Ohms maximum impedance, and 900 mV forward voltage. The part is currently active in production and available in high inventory (47,200 units). It carries ROHS3 compliance and is suitable for direct replacement without circuit redesign.

Full Specification Match Alternatives:

MMSZ5239B-TP (Micro Commercial Co) and MMSZ5239BT1G (onsemi) provide complete electrical and mechanical compatibility. Both maintain the 9.1 V / 500 mW / SOD-123 specification set. Operating temperature range is -55°C to 150°C (versus -65°C to 150°C on the original), which is acceptable for most applications. Both are ROHS3 compliant and actively produced.

Functional Alternatives with Minor Deviations:

MMSZ4696-E3-08 (Vishay) and SZMMSZ4696T1G (onsemi) meet the core 9.1 V / 500 mW / SOD-123 requirements. SZMMSZ4696T1G carries AEC-Q101 automotive qualification. These parts exhibit lower reverse leakage current (1 µA @ 6.9 V versus 3 µA @ 7 V), which is advantageous for precision applications.

Lower Power Alternatives:

BZT52C9V1-G3-18 (Vishay) and BZT52H-C9V1,115 (Nexperia) provide 9.1 V zener voltage with reduced power ratings (410 mW and 375 mW respectively). These are suitable only for applications where the 500 mW rating is not required. BZT52H-C9V1,115 is AEC-Q101 qualified and operates across the full -65°C to 150°C temperature range.

Premium Alternative:

NZH9V1B,115 (NXP Semiconductors) offers tighter voltage tolerance (±2% versus ±5%), lower impedance (8 Ohms), and superior reverse leakage characteristics (500 nA @ 6 V). This part is suitable for applications requiring enhanced precision and is available in high volume (199,284 units).

Frequently Asked Questions (FAQ)

Q: Can MMSZ5239B-7-F be used as a direct replacement for MMSZ5239B-7?

A: Yes. MMSZ5239B-7-F is a direct parametric equivalent with identical electrical specifications. The primary difference is product status (active versus discontinued) and packaging format (Digi-Reel versus standard). No circuit modifications are required.

Q: What is the difference between SOD-123 and SOD-123F packages?

A: SOD-123F is a variant of the SOD-123 package. Both are surface mount packages suitable for the same PCB footprints in most applications. Verify PCB design specifications if package variant compatibility is critical.

Q: Are automotive-qualified alternatives available?

A: Yes. SZMMSZ4696T1G and SZMMSZ5239BT1G from onsemi carry AEC-Q101 automotive qualification. BZT52H-C9V1,115 from Nexperia also qualifies for automotive applications.

Q: Can I use a lower power-rated substitute such as BZT52C9V1-G3-18?

A: Lower power-rated substitutes (410 mW or 375 mW) are acceptable only if circuit analysis confirms that maximum power dissipation does not exceed the substitute part's rating. The original 500 mW specification must be verified against actual application requirements before downrating.

Q: What is the significance of reverse leakage current differences?

A: Reverse leakage current affects circuit performance in precision applications. Lower leakage (1 µA or less) is beneficial for high-impedance circuits. The original specification of 3 µA @ 7 V is standard for general-purpose applications. Substitutes with lower leakage are compatible and often superior.

Q: Which substitute offers the best availability?

A: NZH9V1B,115 from NXP Semiconductors has the highest inventory (199,284 units). MMSZ5239BT1G from onsemi (35,100 units) and MMSZ5239B-7-F from Diodes Incorporated (47,200 units) also provide strong availability.

Q: Are all substitutes RoHS3 compliant?

A: All listed active substitutes carry ROHS3 compliance. The original MMSZ5239B-7 is RoHS non-compliant due to its discontinued status. Compliance requirements should be verified against project specifications.

Q: What is the operating temperature range consideration for substitution?

A: The original part operates from -65°C to 150°C. Most active substitutes operate from -55°C to 150°C. This 10°C difference at the lower end is acceptable for most applications. BZT52H-C9V1,115 and NZH9V1B,115 maintain the full -65°C lower limit.

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