MMSZ5243B Zener Diode 13V 500mW SOD-123 Equivalent & Substitute Parts

Part Overview

The MMSZ5243B is a surface mount zener diode manufactured by onsemi, rated for 13 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 support and procurement. The MMSZ5243B serves voltage regulation and transient protection applications requiring precise 13 V zener characteristics with ±5% tolerance across the operating temperature range of -55°C to 150°C.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	13	V
Tolerance	±5	%
Power - Maximum	500	mW
Impedance (Maximum)	13	Ohms
Current - Reverse Leakage @ Vr	500 nA @ 9.9 V	nA
Voltage - Forward (Maximum) @ If	900 mV @ 10 mA	mV
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount
Package / Case	SOD-123

Substitute Part Grouping Explanation

Substitution of the MMSZ5243B is determined by the following critical parameters: zener voltage (13 V nominal), tolerance (±5%), maximum power rating (500 mW), package type (SOD-123), and operating temperature range (-55°C to 150°C). All substitute parts must maintain these core electrical and mechanical specifications to ensure functional compatibility in existing circuit designs.

Substitute parts are grouped into the following categories:

Direct Equivalents (onsemi Active Parts): Parts with identical electrical specifications, impedance characteristics, and reverse leakage parameters. These include MMSZ5243BT1G, MMSZ13T1G, and MMSZ4700T1G, all rated for 13 V, 500 mW, and SOD-123 packaging with active product status.

Automotive-Grade Equivalents: Parts qualified to AEC-Q101 automotive standards, including SZMMSZ13ET1G, SZMMSZ13T1G, and SZMMSZ5243BT1G. These maintain identical electrical parameters while providing automotive-grade reliability.

Cross-Manufacturer Equivalents: Parts from alternative manufacturers (Micro Commercial Co, Diodes Incorporated) with matching electrical specifications and SOD-123 packaging, including MMSZ5243B-TP and MMSZ5243B-7-F.

Similar Parts (Reduced Power Rating): Parts with identical 13 V zener voltage and SOD-123 packaging but reduced maximum power rating (410 mW) and improved tolerance (±2%), including BZT52B13-G3-08 and BZT52B13-G3-18 from Vishay.

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance (%)	Power (mW)	Zzt (Ohms)	Ir @ Vr (nA)	Vf @ If (mV)	Temp Range (°C)	Package	Status	RoHS
MMSZ5243B	onsemi	13	±5	500	13	500 @ 9.9V	900 @ 10mA	-55 to 150	SOD-123	Obsolete	N/A
MMSZ5243BT1G	onsemi	13	±5	500	13	500 @ 9.9V	900 @ 10mA	-55 to 150	SOD-123	Active	ROHS3
MMSZ13T1G	onsemi	13	±5	500	30	100 @ 8V	900 @ 10mA	-55 to 150	SOD-123	Active	ROHS3
MMSZ4700T1G	onsemi	13	±5	500	N/A	50 @ 9.8V	900 @ 10mA	-55 to 150	SOD-123	Active	ROHS3
SZMMSZ13ET1G	onsemi	13	±5	500	30	100 @ 8V	900 @ 10mA	-55 to 150	SOD-123	Active	ROHS3
SZMMSZ13T1G	onsemi	13	±5	500	30	100 @ 8V	900 @ 10mA	-55 to 150	SOD-123	Active	ROHS3
SZMMSZ5243BT1G	onsemi	13	±5	500	13	500 @ 9.9V	900 @ 10mA	-55 to 150	SOD-123	Active	ROHS3
MMSZ5243B-TP	Micro Commercial Co	13	±5	500	13	500 @ 9.9V	900 @ 10mA	-55 to 150	SOD-123	Active	ROHS3
MMSZ5243B-7-F	Diodes Incorporated	13	±5	500	13	500 @ 9.9V	900 @ 10mA	-65 to 150	SOD-123	Active	ROHS3
BZT52B13-G3-08	Vishay	13	±2	410	25	100 @ 10V	N/A	-65 to 150	SOD-123	Active	ROHS3
BZT52B13-G3-18	Vishay	13	±2	410	25	100 @ 10V	N/A	-65 to 150	SOD-123	Active	ROHS3

Engineering Selection Recommendations

Primary Recommendation - Direct Equivalent: MMSZ5243BT1G (onsemi) is the direct active equivalent to the obsolete MMSZ5243B. This part maintains identical electrical specifications including 13 V zener voltage, ±5% tolerance, 500 mW power rating, 13 Ohms impedance, and 500 nA reverse leakage at 9.9 V. The part is ROHS3 compliant and available in active production status with Cut Tape & Digi-Reel packaging.

Automotive-Grade Alternative: SZMMSZ5243BT1G (onsemi) provides identical electrical performance to MMSZ5243BT1G with additional AEC-Q101 automotive qualification. This part is suitable for applications requiring automotive-grade reliability and traceability.

Cross-Manufacturer Equivalent: MMSZ5243B-7-F (Diodes Incorporated) offers identical electrical specifications with extended operating temperature range (-65°C to 150°C) compared to the original part (-55°C to 150°C). This part is ROHS3 compliant and active in production.

Alternative onsemi Options: MMSZ13T1G and SZMMSZ13T1G provide 13 V zener voltage with 500 mW power rating but feature 30 Ohms impedance and 100 nA reverse leakage at 8 V, representing different impedance characteristics within the same voltage and power class.

Reduced Power Alternative: BZT52B13-G3-08 and BZT52B13-G3-18 (Vishay) maintain 13 V zener voltage and SOD-123 packaging with reduced 410 mW power rating and improved ±2% tolerance. These parts are suitable for applications where the lower power rating is acceptable and tighter tolerance is beneficial.

Cross-Manufacturer Standard: MMSZ5243B-TP (Micro Commercial Co) provides identical specifications to MMSZ5243BT1G with ROHS3 compliance and active production status.

All recommended substitutes are ROHS3 compliant and maintain SOD-123 surface mount packaging compatibility with the original MMSZ5243B design.

Frequently Asked Questions (FAQ)

Q: Can MMSZ5243BT1G directly replace the obsolete MMSZ5243B?

A: Yes. MMSZ5243BT1G is the direct active equivalent with identical electrical specifications: 13 V zener voltage, ±5% tolerance, 500 mW power rating, 13 Ohms impedance, and 500 nA reverse leakage at 9.9 V. Both parts use SOD-123 surface mount packaging and operate across -55°C to 150°C. The primary difference is product status (active vs. obsolete) and packaging format (Cut Tape & Digi-Reel vs. original packaging).

Q: What is the difference between MMSZ13T1G and MMSZ5243BT1G?

A: Both parts share identical 13 V zener voltage, ±5% tolerance, and 500 mW power rating in SOD-123 packaging. The key difference is impedance: MMSZ13T1G specifies 30 Ohms maximum impedance with 100 nA reverse leakage at 8 V, while MMSZ5243BT1G specifies 13 Ohms impedance with 500 nA reverse leakage at 9.9 V. Selection depends on circuit requirements for impedance characteristics and reverse leakage performance.

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

A: Yes. SZMMSZ13ET1G and SZMMSZ13T1G maintain identical electrical specifications to their non-automotive counterparts while providing AEC-Q101 automotive qualification. These parts are suitable for any application requiring the specified 13 V, 500 mW zener characteristics and offer additional reliability assurance through automotive-grade qualification.

Q: Can BZT52B13-G3-08 replace MMSZ5243B in all applications?

A: BZT52B13-G3-08 maintains 13 V zener voltage and SOD-123 packaging but differs in three parameters: reduced 410 mW power rating (vs. 500 mW), improved ±2% tolerance (vs. ±5%), and 25 Ohms impedance (vs. 13 Ohms). This part is suitable for applications where the lower power dissipation is acceptable and tighter tolerance is beneficial. Verify circuit power requirements before substitution.

Q: What is the significance of the "T1G" suffix in onsemi part numbers?

A: The "T1G" suffix indicates the specific packaging and lead-free RoHS3 compliant version of the part. This designation ensures consistency in manufacturing and compliance standards across onsemi's product line.

Q: Does MMSZ5243B-7-F from Diodes Incorporated have any advantages over onsemi equivalents?

A: MMSZ5243B-7-F maintains identical electrical specifications to MMSZ5243BT1G with one advantage: extended operating temperature range of -65°C to 150°C (vs. -55°C to 150°C). This part is suitable for applications requiring operation at lower temperatures. All other parameters including 13 V zener voltage, ±5% tolerance, 500 mW power, and SOD-123 packaging remain identical.

Q: Are all substitute parts ROHS3 compliant?

A: All active substitute parts listed are ROHS3 compliant. The original MMSZ5243B does not specify RoHS status as it is classified as obsolete. All recommended active alternatives meet current RoHS3 compliance requirements.

Q: What packaging options are available for substitute parts?

A: Substitute parts are available in the following packaging formats: Tape & Reel (TR), Cut Tape (CT) & Digi-Reel, and standard tape formats. Selection of packaging format depends on procurement and assembly requirements. All parts maintain SOD-123 component package compatibility.

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