MMSZ5239B Zener Diode 9.1V 500mW SOD-123 Equivalent & Substitute Parts

Part Overview

The MMSZ5239B is a surface mount zener diode manufactured by onsemi, rated for 9.1 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 procurement needs. The part operates across a temperature range of -55°C to 150°C with ±5% voltage tolerance and is ROHS3 compliant with unlimited moisture sensitivity level (MSL 1).

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	9.1	V
Tolerance	±5	%
Power - Max	500	mW
Impedance (Max)	10	Ohms
Current - Reverse Leakage @ Vr	3	µA @ 7 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 MMSZ5239B is determined by the following critical parameters: nominal zener voltage (9.1 V), maximum power rating (500 mW), voltage tolerance (±5%), package type (SOD-123), and operating temperature range (-55°C to 150°C). Parts are grouped into three categories based on substitution compatibility:

Direct Substitutes (Identical Electrical and Mechanical Specifications): Parts meeting all key parameters including 9.1 V zener voltage, 500 mW power rating, ±5% tolerance, SOD-123 package, and -55°C to 150°C operating range. These parts differ only in packaging format (Cut Tape vs. Tape & Reel) or manufacturer designation.

Parametric Equivalents (Automotive Grade): Parts with identical electrical specifications but enhanced automotive qualification (AEC-Q101) and automotive-grade designation. These provide equivalent performance with additional qualification for automotive applications.

Similar Parts (Reduced Power Rating): Parts with matching zener voltage and package but reduced maximum power dissipation (200 mW instead of 500 mW). These are suitable only for applications with lower power requirements.

Upgrade Options (Extended Temperature Range): Parts with identical specifications but extended lower operating temperature limit (-65°C instead of -55°C), providing enhanced performance margin.

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance (%)	Power (mW)	Zzt (Ohms)	Ir @ Vr (µA)	Temp Range (°C)	Grade	Status	Packaging
MMSZ5239B	onsemi	9.1	±5	500	10	3 @ 7V	-55 to 150	Standard	Obsolete	SOD-123
MMSZ4696T1G	onsemi	9.1	±5	500	N/A	1 @ 6.9V	-55 to 150	Standard	Active	CT & Digi-Reel
MMSZ5239BT1G	onsemi	9.1	±5	500	10	3 @ 7V	-55 to 150	Standard	Active	Tape & Reel
MMSZ9V1T1G	onsemi	9.1	±5	500	15	0.5 @ 6V	-55 to 150	Standard	Active	CT & Digi-Reel
SZMMSZ4696T1G	onsemi	9.1	±5	500	N/A	1 @ 6.9V	-55 to 150	Automotive	Active	Tape & Reel
SZMMSZ9V1T1G	onsemi	9.1	±5	500	15	0.5 @ 6V	-55 to 150	Automotive	Active	Tape & Reel
SZMMSZ5239BT1G	onsemi	9.1	±5	500	10	3 @ 7V	-55 to 150	Automotive	Active	Tape & Reel
MMSZ5239B-TP	Micro Commercial Co	9.1	±5	500	10	3 @ 7V	-55 to 150	Standard	Active	Tape & Reel
MMSZ5239B-7-F	Diodes Incorporated	9.1	±5	500	10	3 @ 7V	-65 to 150	Standard	Active	CT & Digi-Reel
BZT52C9V1-TP	Micro Commercial Co	9.1	±6	200	15	0.5 @ 6V	-65 to 150	Standard	Active	CT & Digi-Reel
SZMMSZ5270BT1G	onsemi	91	±5	500	400	0.1 @ 69V	-55 to 150	Automotive	Active	Tape & Reel

Engineering Selection Recommendations

For Direct Replacement (Standard Applications): MMSZ5239BT1G (onsemi) is the primary direct substitute, offering identical electrical specifications and active product status. This part maintains the original 10 Ohm impedance specification and 3 µA reverse leakage characteristic. Packaging is Tape & Reel format suitable for automated assembly.

For Standard Applications with Alternative Packaging: MMSZ4696T1G (onsemi) provides equivalent 9.1 V, 500 mW specifications with improved reverse leakage performance (1 µA @ 6.9V) and is available in Cut Tape & Digi-Reel packaging. MMSZ9V1T1G (onsemi) offers similar performance with 15 Ohm impedance and significantly lower reverse leakage (500 nA @ 6V).

For Automotive Applications: SZMMSZ5239BT1G (onsemi) is the automotive-grade equivalent with AEC-Q101 qualification, maintaining all original electrical parameters including 10 Ohm impedance and 3 µA reverse leakage. SZMMSZ9V1T1G (onsemi) provides automotive qualification with improved leakage characteristics (500 nA @ 6V) and 15 Ohm impedance.

For Extended Temperature Range: MMSZ5239B-7-F (Diodes Incorporated) extends the lower operating temperature to -65°C while maintaining all other specifications, providing enhanced performance margin for temperature-sensitive applications.

For Reduced Power Applications: BZT52C9V1-TP (Micro Commercial Co) is suitable only for applications requiring 200 mW maximum power dissipation. This part features ±6% tolerance and extended temperature range (-65°C to 150°C) but is not interchangeable with the 500 mW rated MMSZ5239B in higher power circuits.

Cross-Manufacturer Option: MMSZ5239B-TP (Micro Commercial Co) provides an active equivalent from an alternative manufacturer with identical specifications and Tape & Reel packaging.

Frequently Asked Questions (FAQ)

Q: Can MMSZ5239BT1G directly replace MMSZ5239B in all applications? A: Yes. MMSZ5239BT1G is a direct substitute with identical electrical specifications (9.1 V, 500 mW, ±5% tolerance, 10 Ohm impedance, 3 µA reverse leakage) and operating temperature range (-55°C to 150°C). The primary difference is packaging format (Tape & Reel vs. original format) and active product status.

Q: What is the difference between standard and automotive-grade parts? A: Automotive-grade parts (SZMMSZ series) carry AEC-Q101 qualification and are designated for automotive applications. They meet additional qualification and reliability requirements. Electrically, SZMMSZ5239BT1G is identical to MMSZ5239BT1G. SZMMSZ9V1T1G and SZMMSZ4696T1G offer improved reverse leakage performance compared to standard equivalents.

Q: Can BZT52C9V1-TP be used as a substitute? A: BZT52C9V1-TP is not a direct substitute. While it maintains the 9.1 V zener voltage and SOD-123 package, the maximum power rating is reduced to 200 mW (versus 500 mW). This part is suitable only for applications with lower power dissipation requirements. Additionally, tolerance is ±6% instead of ±5%.

Q: What are the packaging differences among substitute parts? A: Substitute parts are available in two packaging formats: Cut Tape (CT) & Digi-Reel for component-level handling, and Tape & Reel (TR) for automated assembly. Both formats contain identical components in SOD-123 case style. Selection depends on assembly process requirements.

Q: Why does MMSZ5239B-7-F have an extended temperature range? A: MMSZ5239B-7-F (Diodes Incorporated) extends the lower operating temperature limit to -65°C compared to the original -55°C specification. This provides additional temperature margin for applications operating in extreme cold environments while maintaining all other electrical specifications.

Q: Are there performance differences between onsemi substitute options? A: Yes. MMSZ4696T1G and MMSZ9V1T1G offer improved reverse leakage performance (1 µA and 500 nA respectively, versus 3 µA in MMSZ5239BT1G). MMSZ9V1T1G features 15 Ohm impedance versus 10 Ohm in the original. These differences are negligible for most applications but should be verified for precision voltage regulation circuits.

Q: Is ROHS3 compliance maintained across all substitutes? A: Yes. All active substitute parts listed are ROHS3 compliant with REACH Unaffected status, maintaining environmental compliance requirements of the original MMSZ5239B.

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