MMSZ5252B Zener Diode 24V 500mW SOD-123 Equivalent & Substitute Parts

Part Overview

The MMSZ5252B is a 24 V, 500 mW Zener diode manufactured by onsemi in SOD-123 surface mount packaging. This component is classified as obsolete, though 50,300 units remain in stock. The MMSZ5252B serves as a voltage regulation and transient protection element in electronic circuits requiring 24 V reference voltage with ±5% tolerance.

Due to the obsolete product status, equivalent and substitute parts from active product lines are necessary for new designs and long-term supply chain continuity. Active alternatives maintain identical electrical specifications while offering improved availability and compliance certifications.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	24	V
Tolerance	±5	%
Power - Maximum	500	mW
Impedance (Maximum)	33	Ohms
Current - Reverse Leakage @ Vr	100	nA @ 18 V
Voltage - Forward (Maximum) @ If	900	mV @ 10 mA
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount
Package / Case	SOD-123

Substitute Part Grouping Explanation

Substitution of the MMSZ5252B is determined by the following critical parameters:

Electrical Specifications (Must Match):

Voltage - Zener (Nominal): 24 V
Tolerance: ±5%
Power - Maximum: 500 mW
Operating Temperature Range: -55°C to 150°C
Package / Case: SOD-123

Secondary Electrical Parameters (Allowed Variation):

Impedance (Maximum): 33 Ohms or 70 Ohms
Current - Reverse Leakage @ Vr: 10 nA to 100 nA (at specified voltage)
Voltage - Forward (Maximum) @ If: 900 mV @ 10 mA

Compliance & Availability Criteria:

Product Status: Active (preferred over obsolete)
RoHS Status: ROHS3 Compliant
Moisture Sensitivity Level: 1 (Unlimited)
REACH Status: REACH Unaffected

Substitute parts are grouped into three categories: direct manufacturer equivalents from onsemi (standard grade), automotive-qualified variants (AEC-Q101), and cross-manufacturer alternatives. All listed substitutes maintain the core 24 V, 500 mW, SOD-123 specification set.

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance (%)	Power (mW)	Zzt (Ohms)	Ir @ Vr (nA)	Vf @ If (mV)	Temp Range (°C)	Package	Product Status	Grade	RoHS
MMSZ5252B	onsemi	24	±5	500	33	100 @ 18V	900 @ 10mA	-55 to 150	SOD-123	Obsolete	Standard	N/A
MMSZ24T1G	onsemi	24	±5	500	70	50 @ 16.8V	900 @ 10mA	-55 to 150	SOD-123	Active	Standard	ROHS3
MMSZ4709T1G	onsemi	24	±5	500	N/A	10 @ 18.2V	900 @ 10mA	-55 to 150	SOD-123	Active	Standard	ROHS3
MMSZ5252BT1G	onsemi	24	±5	500	33	100 @ 18V	900 @ 10mA	-55 to 150	SOD-123	Active	Standard	ROHS3
MMSZ5252ET1G	onsemi	24	±5	500	33	100 @ 18V	900 @ 10mA	-55 to 150	SOD-123	Active	Standard	ROHS3
SZMMSZ24T1G	onsemi	24	±5	500	70	50 @ 16.8V	900 @ 10mA	-55 to 150	SOD-123	Active	Automotive	ROHS3
SZMMSZ4709T1G	onsemi	24	±5	500	N/A	10 @ 18.2V	900 @ 10mA	-55 to 150	SOD-123	Active	Automotive	ROHS3
SZMMSZ5252BT1G	onsemi	24	±5	500	33	100 @ 18V	900 @ 10mA	-55 to 150	SOD-123	Active	Automotive	ROHS3
SZMMSZ5252ET1G	onsemi	24	±5	500	33	100 @ 18V	900 @ 10mA	-55 to 150	SOD-123	Active	Automotive	ROHS3
SZMMSZ5252ET3G	onsemi	24	±5	500	33	100 @ 18V	900 @ 10mA	-55 to 150	SOD-123	Active	Automotive	ROHS3
MMSZ5252B-E3-08	Vishay General Semiconductor - Diodes Division	24	±5	500	33	100 @ 18V	N/A	-55 to 150	SOD-123	Active	Standard	ROHS3

Engineering Selection Recommendations

For Standard Industrial Applications:

MMSZ5252BT1G and MMSZ5252ET1G are the primary active equivalents from onsemi. Both maintain identical electrical specifications to the obsolete MMSZ5252B, including 33 Ohms maximum impedance and 100 nA reverse leakage current. Both are ROHS3 compliant and available in active product status. MMSZ5252BT1G is supplied in Cut Tape (CT) & Digi-Reel® packaging, while MMSZ5252ET1G is supplied in Tape & Reel (TR) packaging. Selection between these two depends on procurement and assembly line requirements.

For Automotive Applications (AEC-Q101 Qualified):

SZMMSZ5252BT1G and SZMMSZ5252ET1G are automotive-grade equivalents with AEC-Q101 qualification. These parts maintain the same 24 V, 500 mW, 33 Ohms specification as the original MMSZ5252B and are suitable for automotive circuit protection and voltage regulation applications. SZMMSZ5252BT1G is supplied in Cut Tape (CT) & Digi-Reel® packaging with 30,481 units in stock. SZMMSZ5252ET1G is supplied in Tape & Reel (TR) packaging with 2,626 units in stock.

For Cross-Manufacturer Sourcing:

MMSZ5252B-E3-08 from Vishay General Semiconductor - Diodes Division provides an alternative source for the 24 V, 500 mW, SOD-123 specification. This part is ROHS3 compliant, active in product status, and maintains 33 Ohms maximum impedance with 100 nA reverse leakage current. 23,169 units are in stock.

For Applications with Lower Impedance Tolerance:

MMSZ24T1G and SZMMSZ24T1G feature 70 Ohms maximum impedance compared to the 33 Ohms of the original part. These alternatives are suitable for applications where higher impedance is acceptable. MMSZ24T1G (standard grade) has 55,300 units in stock. SZMMSZ24T1G (automotive grade, AEC-Q101) has 1,600 units in stock.

For Applications with Lower Reverse Leakage Requirements:

MMSZ4709T1G and SZMMSZ4709T1G feature 10 nA reverse leakage current at 18.2 V, compared to 100 nA at 18 V for the original part. These alternatives are suitable for applications requiring lower leakage characteristics. MMSZ4709T1G (standard grade) has 89,200 units in stock. SZMMSZ4709T1G (automotive grade, AEC-Q101) has 7,545 units in stock.

Frequently Asked Questions (FAQ)

Q: Can MMSZ5252BT1G directly replace MMSZ5252B in existing designs?

A: Yes. MMSZ5252BT1G maintains identical electrical specifications: 24 V nominal zener voltage, ±5% tolerance, 500 mW maximum power, 33 Ohms maximum impedance, 100 nA reverse leakage current at 18 V, and -55°C to 150°C operating temperature range. Both use SOD-123 surface mount packaging. The primary difference is product status (active vs. obsolete) and compliance certifications (ROHS3).

Q: What is the difference between MMSZ5252BT1G and MMSZ5252ET1G?

A: Both parts are electrically identical with 24 V, 500 mW, 33 Ohms specifications. The difference is packaging format: MMSZ5252BT1G is supplied in Cut Tape (CT) & Digi-Reel® format, while MMSZ5252ET1G is supplied in Tape & Reel (TR) format. Selection depends on assembly line equipment compatibility and procurement preferences.

Q: When should I use automotive-grade parts (SZMMSZ series)?

A: Automotive-grade parts (SZMMSZ5252BT1G, SZMMSZ5252ET1G, SZMMSZ24T1G, SZMMSZ4709T1G) carry AEC-Q101 qualification and are required for automotive applications subject to automotive industry standards. These parts undergo additional qualification testing and are suitable for under-hood and safety-critical automotive circuits.

Q: What is the significance of impedance variation between 33 Ohms and 70 Ohms?

A: Impedance (Zzt) affects the dynamic response of the zener diode to transient voltage changes. The 33 Ohms specification of MMSZ5252B, MMSZ5252BT1G, and MMSZ5252ET1G provides tighter voltage regulation. The 70 Ohms specification of MMSZ24T1G and SZMMSZ24T1G is acceptable for applications with less stringent transient response requirements. Verify circuit design specifications before substituting between these impedance values.

Q: Can I substitute MMSZ4709T1G for MMSZ5252B?

A: Yes, for applications where lower reverse leakage current is beneficial. MMSZ4709T1G maintains the 24 V, 500 mW, SOD-123 specification but features 10 nA reverse leakage current at 18.2 V compared to 100 nA at 18 V for MMSZ5252B. This lower leakage is advantageous in precision voltage reference and low-power applications. Impedance data is not provided for MMSZ4709T1G.

Q: Is MMSZ5252B-E3-08 from Vishay a suitable alternative?

A: Yes. MMSZ5252B-E3-08 from Vishay General Semiconductor - Diodes Division maintains the 24 V, 500 mW, 33 Ohms, SOD-123 specification. It is ROHS3 compliant and active in product status. This part provides cross-manufacturer sourcing flexibility. Forward voltage data is not provided for this part.

Q: What packaging options are available for substitutes?

A: Substitute parts are available in two packaging formats: Tape & Reel (TR) and Cut Tape (CT) & Digi-Reel®. Tape & Reel is standard for high-volume automated assembly. Cut Tape & Digi-Reel® is suitable for lower-volume production and manual assembly. Verify your assembly equipment compatibility before selecting packaging format.

Q: Are all substitute parts ROHS3 compliant?

A: All active substitute parts listed (MMSZ24T1G, MMSZ4709T1G, MMSZ5252BT1G, MMSZ5252ET1G, SZMMSZ24T1G, SZMMSZ4709T1G, SZMMSZ5252BT1G, SZMMSZ5252ET1G, SZMMSZ5252ET3G, and MMSZ5252B-E3-08) are ROHS3 compliant. The original MMSZ5252B does not list RoHS status.

Q: What is the Moisture Sensitivity Level (MSL) for these parts?

A: All listed parts have Moisture Sensitivity Level 1 (Unlimited), indicating no moisture sensitivity restrictions during storage and handling.

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