MMSZ5237B Zener Diode Equivalent & Substitute Parts

Part Overview

The MMSZ5237B is an 8.2 V, 500 mW surface mount zener diode in SOD-123 packaging manufactured by onsemi. This part is classified as obsolete, indicating that direct procurement from the original manufacturer may be limited or unavailable. Equivalent and substitute parts are necessary to maintain design continuity, ensure supply chain reliability, and support ongoing production requirements. The substitute parts listed maintain electrical and mechanical compatibility while offering active product status and improved availability.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	8.2	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 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 MMSZ5237B is determined by strict equivalence across the following critical parameters:

Electrical Parameters:

Zener voltage: 8.2 V nominal
Power dissipation: 500 mW maximum
Voltage tolerance: ±5%
Forward voltage: 900 mV maximum at 10 mA
Operating temperature range: -55°C to 150°C minimum

Mechanical Parameters:

Package type: SOD-123 surface mount
Mounting configuration: Surface mount only

Compliance Parameters:

Moisture sensitivity: MSL 1 (Unlimited)
RoHS status: ROHS3 Compliant (for active parts)

Parts are grouped into three categories based on substitution relationship:

Direct Substitutes: Parts with identical electrical specifications and active product status, differing only in packaging format (Tape & Reel, Cut Tape, or Digi-Reel) or manufacturer.

Parametric Equivalents: Parts meeting all electrical and mechanical requirements with active product status, including automotive-grade variants with AEC-Q101 qualification.

Upgrade Options: Parts exceeding the original specification in operating temperature range or offering enhanced reliability certifications.

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ohms)	Ir @ Vr (µA)	Vf (mV)	Temp Range (°C)	Package	Status	Grade
MMSZ5237B	onsemi	8.2	±5%	500	8	3 @ 6.5V	900 @ 10mA	-55 to 150	SOD-123	Obsolete	Commercial
MMSZ4694T1G	onsemi	8.2	—	500	—	1 @ 6.2V	900 @ 10mA	-55 to 150	SOD-123	Active	Commercial
MMSZ5237BT1G	onsemi	8.2	±5%	500	8	3 @ 6.5V	900 @ 10mA	-55 to 150	SOD-123	Active	Commercial
MMSZ8V2T1G	onsemi	8.2	±5%	500	15	0.7 @ 5V	900 @ 10mA	-55 to 150	SOD-123	Active	Commercial
SZMMSZ4694T1G	onsemi	8.2	±5%	500	—	1 @ 6.2V	900 @ 10mA	-55 to 150	SOD-123	Active	Automotive
SZMMSZ8V2T1G	onsemi	8.2	±5%	500	15	0.7 @ 5V	900 @ 10mA	-55 to 150	SOD-123	Active	Automotive
MMSZ5237ET1G	onsemi	8.2	±5%	500	8	3 @ 6.5V	900 @ 10mA	-55 to 150	SOD-123	Active	Commercial
SZMMSZ5237BT1G	onsemi	8.2	±5%	500	8	3 @ 6.5V	900 @ 10mA	-55 to 150	SOD-123	Active	Automotive
SZMMSZ5237ET1G	onsemi	8.2	±5%	500	8	3 @ 6.5V	900 @ 10mA	-55 to 150	SOD-123	Active	Automotive
MMSZ5237B-TP	Micro Commercial Co	8.2	±5%	500	8	3 @ 6.5V	900 @ 10mA	-55 to 150	SOD-123	Active	Commercial
MMSZ5237B-7-F	Diodes Incorporated	8.2	±5%	500	8	3 @ 6.5V	900 @ 10mA	-65 to 150	SOD-123	Active	Commercial

Engineering Selection Recommendations

For Standard Commercial Applications:

MMSZ5237BT1G (onsemi) is the direct functional equivalent with identical electrical specifications and active product status. This part maintains the original ±5% tolerance, 8 Ohm impedance, and 3 µA reverse leakage characteristics. It is available in Cut Tape and Digi-Reel packaging formats.

MMSZ5237ET1G (onsemi) provides an alternative from the same manufacturer with identical specifications and active status, suitable for applications requiring Tape & Reel packaging.

MMSZ5237B-TP (Micro Commercial Co) offers equivalent specifications with active product status and ROHS3 compliance, providing supply diversification from an alternative manufacturer.

MMSZ5237B-7-F (Diodes Incorporated) extends the operating temperature range to -65°C to 150°C, providing enhanced low-temperature performance while maintaining all other electrical specifications. This part is suitable for applications requiring extended temperature operation.

For Automotive Applications:

SZMMSZ5237BT1G (onsemi) is an automotive-grade equivalent with AEC-Q101 qualification, identical electrical specifications, and active product status. This part is required for automotive designs and meets automotive reliability standards.

SZMMSZ5237ET1G (onsemi) provides an automotive-grade alternative with AEC-Q101 qualification and identical specifications.

For Applications with Reduced Leakage Requirements:

MMSZ8V2T1G (onsemi) maintains the 8.2 V zener voltage and 500 mW power rating but features reduced reverse leakage (0.7 µA @ 5 V versus 3 µA @ 6.5 V) and higher impedance (15 Ohms). This part is suitable for low-leakage circuit designs.

SZMMSZ8V2T1G (onsemi) provides the same low-leakage characteristics with automotive-grade AEC-Q101 qualification.

For Applications with Lower Leakage and Reduced Impedance Sensitivity:

MMSZ4694T1G (onsemi) offers reduced reverse leakage (1 µA @ 6.2 V) while maintaining the 8.2 V zener voltage and 500 mW power rating. This part is suitable for applications where leakage current is a design constraint.

SZMMSZ4694T1G (onsemi) provides the same leakage characteristics with automotive-grade AEC-Q101 qualification.

Frequently Asked Questions (FAQ)

Q: Can MMSZ5237BT1G directly replace MMSZ5237B in existing designs?

A: Yes. MMSZ5237BT1G is a direct functional equivalent with identical electrical specifications (8.2 V nominal, ±5% tolerance, 500 mW, 8 Ohm impedance, 3 µA reverse leakage). Both parts use SOD-123 surface mount packaging. The primary difference is product status: MMSZ5237BT1G is active while MMSZ5237B is obsolete. No circuit modifications are required.

Q: What is the difference between MMSZ5237BT1G and MMSZ8V2T1G?

A: Both parts share the same 8.2 V zener voltage, ±5% tolerance, and 500 mW power rating in SOD-123 packaging. The key differences are: MMSZ8V2T1G has lower reverse leakage (0.7 µA @ 5 V versus 3 µA @ 6.5 V) and higher impedance (15 Ohms versus 8 Ohms). Select MMSZ8V2T1G for applications requiring minimal leakage current; select MMSZ5237BT1G for applications requiring lower impedance.

Q: Are automotive-grade parts (SZMMSZ series) compatible with commercial applications?

A: Yes. Automotive-grade parts with AEC-Q101 qualification meet or exceed commercial specifications. SZMMSZ5237BT1G and SZMMSZ5237ET1G are fully compatible with commercial designs and provide enhanced reliability through automotive qualification. They are suitable for any application using the commercial equivalent.

Q: What is the significance of the packaging designation (T1G, -TP, -7-F)?

A: Packaging designations indicate the delivery format and manufacturer-specific coding. T1G indicates Tape & Reel packaging from onsemi. -TP indicates Tape & Reel from Micro Commercial Co. -7-F indicates Tape & Reel from Diodes Incorporated. All three formats are compatible with standard surface mount assembly equipment. Select based on supply chain availability and procurement requirements.

Q: Does MMSZ5237B-7-F offer any advantages over MMSZ5237BT1G?

A: MMSZ5237B-7-F extends the operating temperature range to -65°C (versus -55°C for MMSZ5237BT1G). All other electrical specifications are identical. Select MMSZ5237B-7-F only if your application requires operation below -55°C.

Q: Can I use MMSZ4694T1G as a substitute for MMSZ5237B?

A: MMSZ4694T1G is electrically compatible with identical zener voltage (8.2 V) and power rating (500 mW). However, it has lower reverse leakage (1 µA @ 6.2 V versus 3 µA @ 6.5 V) and does not specify impedance. Use MMSZ4694T1G only if your circuit design accommodates the lower leakage specification.

Q: Are all substitute parts ROHS3 compliant?

A: All active substitute parts listed are ROHS3 compliant. The original MMSZ5237B (obsolete) does not specify RoHS status. All recommended substitutes meet current environmental compliance requirements.

Q: What is the difference between Cut Tape (CT) and Tape & Reel (TR) packaging?

A: Both formats use identical SOD-123 components on standard 8 mm tape. Cut Tape is supplied in shorter lengths for manual or small-batch assembly. Tape & Reel is supplied on full reels for high-volume automated assembly. Electrical performance is identical; selection depends on production volume and assembly process requirements.

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