MMBZ5253B Equivalent & Substitute Parts

Part Overview

The MMBZ5253B is a Zener diode rated at 25 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)	25	V
Tolerance	±5	%
Power - Max	350	mW
Impedance (Max)	35	Ohms
Current - Reverse Leakage @ Vr	100 nA @ 19 V	nA
Voltage - Forward (Vf) (Max) @ If	900 mV @ 10 mA	mV
Operating Temperature	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	TO-236-3, SC-59, SOT-23-3	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the MMBZ5253B is determined by the following critical parameters:

Electrical Compatibility Requirements:

Zener voltage: 25 V nominal
Tolerance: ±5%
Impedance (Max): 35 Ohms
Current - Reverse Leakage @ Vr: 100 nA @ 19 V
Voltage - Forward (Vf) (Max) @ If: 900 mV @ 10 mA

Mechanical Compatibility Requirements:

Mounting Type: Surface Mount
Package / Case: TO-236-3, SC-59, SOT-23-3
Moisture Sensitivity Level: 1 (Unlimited)

Operational Requirements:

Operating Temperature Range: -55°C to 150°C minimum

Substitute parts are grouped into two categories based on power rating alignment:

Category 1 - Reduced Power Rating (225 mW): MMBZ5253BLT1G and SZMMBZ5253BLT1G maintain all electrical parameters but operate at 225 mW maximum power. These are suitable for applications where the full 350 mW rating is not required.

Category 2 - Equivalent or Increased Power Rating (300-410 mW): CMPZ5253B TR PBFREE, CZRT5253B-G, and MMBZ5253B_R1_00001 provide power ratings at or above the original 350 mW specification, ensuring full functional equivalence.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power - Max	Zzt (Max)	Reverse Leakage @ Vr	Vf (Max) @ If	Temp Range	Package	Product Status
MMBZ5253B	onsemi	25 V	±5%	350 mW	35 Ω	100 nA @ 19 V	900 mV @ 10 mA	-55 to 150°C	SOT-23-3	Obsolete
MMBZ5253BLT1G	onsemi	25 V	±5%	225 mW	35 Ω	100 nA @ 19 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Active
SZMMBZ5253BLT1G	onsemi	25 V	±5%	225 mW	35 Ω	100 nA @ 19 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Active
CMPZ5253B TR PBFREE	Central Semiconductor Corp	25 V	±5%	350 mW	35 Ω	100 nA @ 19 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Active
CZRT5253B-G	Comchip Technology	25 V	±5%	300 mW	35 Ω	100 nA @ 19 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Active
MMBZ5253B_R1_00001	Panjit International Inc.	25 V	±5%	410 mW	35 Ω	100 nA @ 19 V	900 mV @ 10 mA	-55 to 150°C	SOT-23-3	Active

Engineering Selection Recommendations

For Direct Replacement with Equivalent Power Rating:

CMPZ5253B TR PBFREE (Central Semiconductor Corp) provides the closest functional equivalence to the MMBZ5253B. It maintains the 350 mW power rating, identical electrical specifications, and is RoHS3 compliant with active product status. This part is recommended for applications requiring the full original power dissipation capability.

MMBZ5253B_R1_00001 (Panjit International Inc.) offers increased power rating at 410 mW, exceeding the original specification. This part is suitable for applications with higher thermal margins or increased power dissipation requirements. RoHS3 compliance and active status support long-term availability.

For Power-Constrained Applications:

MMBZ5253BLT1G and SZMMBZ5253BLT1G (both onsemi) are suitable substitutes where maximum power dissipation does not exceed 225 mW. SZMMBZ5253BLT1G includes AEC-Q101 automotive qualification, making it appropriate for automotive applications. Both parts feature extended operating temperature range (-65 to 150°C) and RoHS3 compliance.

For Mid-Range Power Requirements:

CZRT5253B-G (Comchip Technology) provides 300 mW power rating, positioning it between reduced and full-power options. This part is suitable for applications requiring moderate power dissipation with RoHS3 compliance and active product status.

All substitute parts maintain identical zener voltage (25 V), tolerance (±5%), impedance (35 Ω), reverse leakage characteristics, and forward voltage specifications. Package compatibility (SOT-23-3) and moisture sensitivity level (MSL 1) are uniform across all options.

Frequently Asked Questions (FAQ)

Q: Can MMBZ5253BLT1G replace MMBZ5253B in all applications?

A: MMBZ5253BLT1G is electrically equivalent but rated at 225 mW versus the original 350 mW. It is suitable only for applications where power dissipation does not exceed 225 mW. Verify circuit power requirements before substitution.

Q: What is the difference between MMBZ5253BLT1G and SZMMBZ5253BLT1G?

A: Both parts are electrically and mechanically identical. SZMMBZ5253BLT1G includes AEC-Q101 automotive qualification, making it appropriate for automotive applications. Selection depends on application requirements.

Q: Is CMPZ5253B TR PBFREE a direct replacement for MMBZ5253B?

A: Yes. CMPZ5253B TR PBFREE maintains the 350 mW power rating and all electrical specifications of the MMBZ5253B. It is manufactured by Central Semiconductor Corp and carries active product status with RoHS3 compliance.

Q: Why does MMBZ5253B_R1_00001 have a higher power rating (410 mW)?

A: MMBZ5253B_R1_00001 is manufactured by Panjit International Inc. with enhanced thermal characteristics. The increased 410 mW rating provides additional design margin and is fully compatible with the original 350 mW specification.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All active substitute parts listed carry RoHS3 compliance status. The original MMBZ5253B does not specify RoHS status due to its obsolete classification.

Q: Do substitute parts have the same operating temperature range?

A: The original MMBZ5253B operates from -55°C to 150°C. Most substitute parts extend the lower limit to -65°C, providing improved low-temperature performance. MMBZ5253B_R1_00001 maintains the original -55°C lower limit.

Q: Is the SOT-23-3 package identical across all parts?

A: Yes. All parts use the SOT-23-3 package (also designated TO-236-3 or SC-59). Physical dimensions and pin configurations are identical, ensuring direct PCB compatibility.

Q: What is the significance of MSL 1 (Unlimited) rating?

A: MSL 1 indicates unlimited shelf life without moisture baking requirements. All listed parts carry this rating, ensuring consistent handling and storage procedures.

Q: Can I use CZRT5253B-G as a substitute if my application requires 350 mW?

A: CZRT5253B-G is rated at 300 mW, which is below the original 350 mW specification. Use this part only if your application power dissipation does not exceed 300 mW. For full 350 mW capability, select CMPZ5253B TR PBFREE or MMBZ5253B_R1_00001.

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