MM5Z39VT1G Equivalent & Substitute Parts

Part Overview

The MM5Z39VT1G is a Zener Diode rated at 39 V with 500 mW power dissipation in SOD-523 surface mount packaging, manufactured by onsemi. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The 39 V Zener voltage with ±5.1% tolerance and SOD-523 package form the basis for identifying compatible alternatives from active manufacturers.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	39	V
Tolerance	±5.1%	%
Power - Max	500	mW
Impedance (Max)	130	Ohms
Current - Reverse Leakage @ Vr	50	nA @ 27.3 V
Voltage - Forward (Max) @ If	900	mV @ 10 mA
Operating Temperature Range	-65 to 150	°C
Mounting Type	Surface Mount	-
Package / Case	SOD-523	-
Moisture Sensitivity Level	1 (Unlimited)	-

Substitute Part Grouping Explanation

Substitution of the MM5Z39VT1G is determined by the following critical parameters:

Primary Substitution Criteria:

Zener voltage: 39 V nominal
Zener voltage tolerance: ±5% or tighter
Power dissipation: equal to or greater than 500 mW
Reverse leakage current: 50 nA @ 27.3 V or lower
Operating temperature range: -65°C to 150°C minimum
Surface mount technology
Moisture sensitivity level: 1 (Unlimited)

Package Compatibility: Substitutes are grouped by package type. The primary package SOD-523 allows direct replacement. Alternative packages (SOD-323F, SOD-123F, 0603/SOD-523F) require PCB layout modification but maintain electrical equivalence when other parameters align.

Tolerance and Compliance: Active substitute parts from Nexperia USA Inc. and Comchip Technology provide ROHS3 compliance and automotive-grade qualifications (AEC-Q100, AEC-Q101), offering improved reliability compared to the obsolete onsemi part.

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance (%)	Power (mW)	Zzt (Ohms)	Ir @ Vr (nA)	Vf @ If (mV)	Temp Range (°C)	Package	Status
MM5Z39VT1G	onsemi	39	±5.1	500	130	50 @ 27.3 V	900 @ 10 mA	-65 to 150	SOD-523	Obsolete
BZX585-C39,115	Nexperia USA Inc.	39	±5	300	130	50 @ 27.3 V	1100 @ 100 mA	-65 to 150	SOD-523	Active
BZX585-B39,115	Nexperia USA Inc.	39	±2	300	130	50 @ 27.3 V	1100 @ 100 mA	-65 to 150	SOD-523	Active
BZX84J-C39,115	Nexperia USA Inc.	39	±5	550	75	50 @ 27.3 V	1100 @ 100 mA	-65 to 150	SOD-323F	Active
BZX84J-B39,115	Nexperia USA Inc.	39	±2	550	75	50 @ 27.3 V	1100 @ 100 mA	-65 to 150	SOD-323F	Active
BZT52H-C39,115	Nexperia USA Inc.	39	±5	375	75	50 @ 27.3 V	900 @ 10 mA	-65 to 150	SOD-123F	Active
CZRU52C39	Comchip Technology	39	±5	150	90	100 @ 29 V	900 @ 10 mA	-55 to 125	0603/SOD-523F	Active
CZRUR52C39	Comchip Technology	39	±5	150	90	100 @ 29 V	900 @ 10 mA	-55 to 125	0603/SOD-523F	Active

Engineering Selection Recommendations

Direct Package Replacement (SOD-523): BZX585-C39,115 and BZX585-B39,115 are the primary substitutes for direct PCB replacement. Both maintain the SOD-523 package footprint. BZX585-B39,115 offers superior tolerance (±2%) compared to the original ±5.1% specification. Both parts are AEC-Q100 qualified and ROHS3 compliant. Power dissipation is reduced to 300 mW, which is acceptable for applications not requiring the full 500 mW capability of the original part.

Higher Power Capability (SOD-323F Package): BZX84J-C39,115 and BZX84J-B39,115 provide 550 mW power dissipation, exceeding the original 500 mW specification. These parts require PCB layout modification due to SOD-323F package geometry. Both are AEC-Q101 qualified with ROHS3 compliance. BZX84J-B39,115 provides ±2% tolerance.

Alternative Package Options (SOD-123F): BZT52H-C39,115 offers 375 mW power dissipation in SOD-123F package. This part is AEC-Q101 qualified and ROHS3 compliant. PCB layout modification is required.

Low Power Applications (0603/SOD-523F): CZRU52C39 and CZRUR52C39 are suitable for applications requiring 150 mW or less. Operating temperature range is limited to -55°C to 125°C. These parts are ROHS3 compliant but lack automotive qualification.

Product Status Consideration: All recommended substitutes are active products from established manufacturers with current production and supply availability, eliminating obsolescence risk associated with the MM5Z39VT1G.

Frequently Asked Questions (FAQ)

Q: Can BZX585-C39,115 directly replace MM5Z39VT1G without PCB modification?

A: Yes. BZX585-C39,115 maintains the SOD-523 package footprint and pinout. No PCB layout changes are required. The 39 V Zener voltage, ±5% tolerance, and operating temperature range (-65°C to 150°C) are compatible. Power dissipation is reduced from 500 mW to 300 mW, which is acceptable for most applications.

Q: What is the difference between BZX585-B39,115 and BZX585-C39,115?

A: Both parts are identical except for Zener voltage tolerance. BZX585-B39,115 has ±2% tolerance, while BZX585-C39,115 has ±5% tolerance. Both maintain 39 V nominal Zener voltage, SOD-523 package, and 300 mW power rating. Selection depends on circuit tolerance requirements.

Q: Why do BZX84J series parts have lower impedance (75 Ohms vs. 130 Ohms)?

A: Lower impedance is a characteristic of the BZX84J series design. This provides better voltage regulation performance in certain applications. The 39 V Zener voltage and reverse leakage current remain equivalent to the original part.

Q: Can CZRU52C39 be used in place of MM5Z39VT1G?

A: CZRU52C39 is suitable only for applications requiring 150 mW or less power dissipation. The operating temperature range is limited to -55°C to 125°C compared to the original -65°C to 150°C. PCB layout modification is required due to 0603 package geometry. Reverse leakage current is higher at 100 nA @ 29 V.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All active substitute parts listed are ROHS3 compliant. The obsolete MM5Z39VT1G does not carry RoHS certification.

Q: Which substitute offers the best automotive qualification?

A: BZX84J-C39,115 and BZX84J-B39,115 carry AEC-Q101 qualification. BZX585-B39,115 and BZX585-C39,115 carry AEC-Q100 qualification. Both qualifications are automotive-grade. CZRU52C39 and CZRUR52C39 lack automotive qualification.

Q: What is the impact of using BZT52H-C39,115 with reduced power rating (375 mW)?

A: BZT52H-C39,115 is suitable for applications where peak power dissipation does not exceed 375 mW. The 39 V Zener voltage, ±5% tolerance, and -65°C to 150°C operating range match the original specification. Forward voltage (900 mV @ 10 mA) is identical to the original part.

Q: Can multiple substitute parts be used interchangeably in the same design?

A: No. Each substitute part has distinct electrical characteristics (power rating, impedance, tolerance). Circuit design must specify a single part number. Substitution between different part numbers requires circuit re-evaluation.

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