MMBZ5244B Equivalent & Substitute Parts

Part Overview

The MMBZ5244B is a Zener diode rated at 14 V nominal voltage with 350 mW maximum power dissipation in a surface mount SOT-23-3 package. Manufactured by onsemi, this component is classified as obsolete. Due to its obsolete status, equivalent and substitute parts from active manufacturers are necessary for new designs and ongoing production requirements. Substitute parts maintain the core electrical specifications while offering improved availability and active product support.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	14	V
Tolerance	±5	%
Power - Max	350	mW
Impedance (Max)	15	Ohms
Current - Reverse Leakage @ Vr	100	nA @ 10 V
Voltage - Forward (Vf) (Max) @ If	900	mV @ 10 mA
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount
Package / Case	TO-236-3, SC-59, SOT-23-3

Substitute Part Grouping Explanation

Substitution of the MMBZ5244B is determined by the following critical parameters:

Primary Substitution Criteria:

Voltage - Zener (Nom): 14 V
Tolerance: ±5%
Impedance (Max): 15 Ohms
Current - Reverse Leakage @ Vr: 100 nA @ 10 V
Voltage - Forward (Vf) (Max) @ If: 900 mV @ 10 mA
Package / Case: TO-236-3, SC-59, SOT-23-3
Mounting Type: Surface Mount

Secondary Consideration:

Power - Max: 350 mW (direct equivalents) or 225 mW (reduced power variants)

Substitute parts are grouped into three categories:

Direct Electrical Equivalents (350 mW): Parts maintaining identical power rating, zener voltage, and impedance specifications. These provide one-to-one replacement capability.
Reduced Power Variants (225 mW): Parts with identical zener voltage and impedance but lower maximum power dissipation. These are suitable for applications where the full 350 mW power capability is not required.
Cross-Manufacturer Equivalents: Parts from alternative manufacturers meeting identical electrical specifications and package requirements.

Parts with different zener voltages (16 V, 18 V) or different package types (SOT-323) are listed for reference but do not constitute direct substitutes.

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance (%)	Power (mW)	Zzt (Ohms)	Vf (mV)	Temp Range (°C)	Package	Status
MMBZ5244B	onsemi	14	±5	350	15	900	-55 to 150	SOT-23-3	Obsolete
MMBZ5244BLT1G	onsemi	14	±5	225	15	900	-65 to 150	SOT-23-3	Active
SZMMBZ5244BLT1G	onsemi	14	±5	225	15	900	-65 to 150	SOT-23-3	Active
MMBZ5244BQ-7-F	Diodes Incorporated	14	±5	350	15	900	-65 to 150	SOT-23-3	Active
CMPZ5244B TR PBFREE	Central Semiconductor Corp	14	±5	350	13	900	-65 to 150	SOT-23-3	Active
MMBZ5244B-7-F	Diodes Incorporated	14	±5	350	15	900	-65 to 150	SOT-23-3	Active
MMBZ5244B_R1_00001	Panjit International Inc.	14	±5	410	15	N/A	-55 to 150	SOT-23-3	Active
MMBZ5244B-TP	Micro Commercial Co	14	±5	350	15	900	-55 to 150	SOT-23-3	Active
MMBZ5246BW-7-F	Diodes Incorporated	16	±5	200	17	900	-65 to 150	SOT-323	Active
MMBZ5248B-7-F	Diodes Incorporated	18	±5	350	21	900	-65 to 150	SOT-23-3	Active

Engineering Selection Recommendations

Direct Replacement (14 V, 350 mW, SOT-23-3):

The following parts provide direct electrical and mechanical equivalence to the MMBZ5244B:

MMBZ5244BQ-7-F (Diodes Incorporated): Active product with AEC-Q101 automotive qualification. Identical electrical specifications and operating temperature range extended to -65°C. RoHS3 compliant.
MMBZ5244B-7-F (Diodes Incorporated): Active product with identical electrical specifications. RoHS3 compliant. Extended operating temperature range to -65°C.
MMBZ5244B-TP (Micro Commercial Co): Active product with identical electrical specifications and power rating. RoHS3 compliant. Operating temperature range matches original specification.
CMPZ5244B TR PBFREE (Central Semiconductor Corp): Active product with 14 V zener voltage and 350 mW power rating. Impedance specification of 13 Ohms is within acceptable tolerance. RoHS3 compliant. Extended operating temperature range to -65°C.
MMBZ5244B_R1_00001 (Panjit International Inc.): Active product with 14 V zener voltage. Power rating of 410 mW exceeds original specification, providing additional thermal margin. RoHS3 compliant.

Reduced Power Alternative (14 V, 225 mW, SOT-23-3):

MMBZ5244BLT1G (onsemi): Active product from original manufacturer. Maintains 14 V zener voltage and 15 Ohm impedance. Power rating reduced to 225 mW. Extended operating temperature range to -65°C. RoHS3 compliant. Suitable for applications not requiring full 350 mW dissipation.
SZMMBZ5244BLT1G (onsemi): Active product with automotive grade designation and AEC-Q101 qualification. Identical electrical specifications to MMBZ5244BLT1G. Extended operating temperature range to -65°C. RoHS3 compliant.

Non-Equivalent Parts (Reference Only):

MMBZ5246BW-7-F: 16 V zener voltage. Different package (SOT-323). Not a direct substitute.
MMBZ5248B-7-F: 18 V zener voltage. Not a direct substitute.

Frequently Asked Questions (FAQ)

Q: Can MMBZ5244BLT1G replace MMBZ5244B in all applications?

A: MMBZ5244BLT1G maintains identical zener voltage (14 V), tolerance (±5%), impedance (15 Ohms), and forward voltage specifications. The primary difference is reduced maximum power dissipation (225 mW versus 350 mW). Substitution is valid for applications where the circuit does not require the full 350 mW power capability. Thermal analysis of the specific application is necessary to confirm adequate power margin.

Q: What is the difference between MMBZ5244BQ-7-F and MMBZ5244B-7-F?

A: Both parts are manufactured by Diodes Incorporated and provide identical electrical specifications (14 V, 350 mW, SOT-23-3). MMBZ5244BQ-7-F carries automotive grade designation with AEC-Q101 qualification. Both are active products with RoHS3 compliance and extended operating temperature range to -65°C.

Q: Is CMPZ5244B TR PBFREE a suitable replacement?

A: CMPZ5244B TR PBFREE from Central Semiconductor Corp meets the primary electrical requirements: 14 V zener voltage, ±5% tolerance, 350 mW power rating, and SOT-23-3 package. The impedance specification of 13 Ohms is lower than the original 15 Ohms maximum, which is acceptable. The part is RoHS3 compliant and active. Direct substitution is supported.

Q: Why is MMBZ5244B_R1_00001 listed as a substitute if it has 410 mW power rating?

A: MMBZ5244B_R1_00001 from Panjit International Inc. maintains the critical electrical specifications: 14 V zener voltage, ±5% tolerance, 15 Ohm impedance, and SOT-23-3 package. The higher power rating (410 mW versus 350 mW) provides additional thermal capability and does not create incompatibility. This part is suitable for applications where enhanced power dissipation margin is beneficial.

Q: Can MMBZ5246BW-7-F or MMBZ5248B-7-F be used as substitutes?

A: No. MMBZ5246BW-7-F has a zener voltage of 16 V and uses a different package (SOT-323). MMBZ5248B-7-F has a zener voltage of 18 V. Both differ from the required 14 V specification and are not direct substitutes. These parts are listed for reference only.

Q: What is the significance of AEC-Q101 qualification?

A: AEC-Q101 qualification indicates the part meets automotive industry reliability standards. Parts carrying this qualification (SZMMBZ5244BLT1G and MMBZ5244BQ-7-F) are suitable for automotive applications requiring enhanced reliability documentation and traceability.

Q: Are all substitute parts RoHS3 compliant?

A: All listed substitute parts are RoHS3 compliant. The original MMBZ5244B does not specify RoHS status. All active alternatives meet current environmental compliance requirements.

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

A: Cut Tape (CT) and Digi-Reel® packaging (MMBZ5244BLT1G) provides smaller quantity reels suitable for lower-volume applications. Tape & Reel (TR) packaging provides standard reel quantities for higher-volume production. Electrical specifications remain identical; packaging format differs only in quantity and reel configuration.

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