MMBZ5259B-TP Equivalent & Substitute Parts

Part Overview

The MMBZ5259B-TP is a Zener diode manufactured by Micro Commercial Co, rated at 39 V nominal with 350 mW maximum power dissipation in a surface mount SOT-23 package. This component is classified as Active and maintains full RoHS3 compliance. Zener diodes of this specification are used in voltage regulation, overvoltage protection, and reference voltage circuits. Substitute parts are identified to address inventory availability, extended temperature range requirements, or alternative sourcing needs while maintaining electrical and mechanical compatibility.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	39	V
Tolerance	±5%	%
Power - Max	350	mW
Impedance (Max)	80	Ohms
Current - Reverse Leakage @ Vr	100	nA @ 30 V
Voltage - Forward (Vf) (Max) @ If	900	mV @ 10 mA
Operating Temperature	-55 to 150	°C
Package / Case	SOT-23-3 (TO-236)	—
Mounting Type	Surface Mount	—

Substitute Part Grouping Explanation

Substitution eligibility for the MMBZ5259B-TP is determined by the following critical parameters:

Electrical Compatibility Requirements:

Zener voltage (Nom): 39 V ±5%
Impedance (Max): 80 Ohms
Reverse leakage current: 100 nA @ 30 V
Forward voltage: 900 mV @ 10 mA maximum

Mechanical & Package Compatibility:

Package type: SOT-23-3 (TO-236, SC-59)
Mounting: Surface Mount
Tape & Reel packaging format

Compliance & Status:

Product Status: Active
RoHS3 Compliance: Required
REACH Status: Unaffected

The MMBZ5259BLT1G qualifies as a direct substitute based on matching electrical parameters and package specifications. The primary distinction is maximum power rating (225 mW vs. 350 mW) and extended lower operating temperature limit (-65°C vs. -55°C).

Parameter Comparison

Parameter	MMBZ5259B-TP (Micro Commercial Co)	MMBZ5259BLT1G (onsemi)	Match Status
Voltage - Zener (Nom)	39 V	39 V	Identical
Tolerance	±5%	±5%	Identical
Power - Max	350 mW	225 mW	Substitute rated lower
Impedance (Max)	80 Ohms	80 Ohms	Identical
Current - Reverse Leakage @ Vr	100 nA @ 30 V	100 nA @ 30 V	Identical
Voltage - Forward (Vf) (Max) @ If	900 mV @ 10 mA	900 mV @ 10 mA	Identical
Operating Temperature	-55°C to 150°C	-65°C to 150°C	Substitute extends lower range
Package / Case	SOT-23-3 (TO-236)	SOT-23-3 (TO-236)	Identical
Mounting Type	Surface Mount	Surface Mount	Identical
RoHS3 Compliance	Compliant	Compliant	Identical

Engineering Selection Recommendations

MMBZ5259B-TP (Primary Part): Select this part when the application requires the full 350 mW power dissipation rating and operates within the -55°C to 150°C temperature range. This part is manufactured by Micro Commercial Co and maintains Active product status with full RoHS3 compliance.

MMBZ5259BLT1G (Substitute Part): This onsemi equivalent is suitable for applications where power dissipation does not exceed 225 mW and extended low-temperature operation to -65°C is required. The substitute maintains identical zener voltage, impedance, leakage current, and forward voltage specifications. Both parts are Active products with RoHS3 compliance and REACH Unaffected status. The substitute offers higher inventory availability (3400 pcs vs. 799 pcs) and extended temperature range capability.

Selection between these parts depends on circuit power budget requirements and minimum operating temperature specifications. Both parts are electrically and mechanically compatible within their respective power ratings.

Frequently Asked Questions (FAQ)

Q: Can MMBZ5259BLT1G replace MMBZ5259B-TP in all applications?

A: The MMBZ5259BLT1G is compatible with MMBZ5259B-TP when circuit power dissipation does not exceed 225 mW. If the application requires the full 350 mW rating, the substitute is not appropriate. Both parts share identical zener voltage (39 V), impedance (80 Ohms), and leakage characteristics.

Q: What is the difference in power rating between these parts?

A: The MMBZ5259B-TP is rated for 350 mW maximum power dissipation, while the MMBZ5259BLT1G is rated for 225 mW. This difference affects thermal management and maximum current handling capability in the circuit.

Q: Are the packages identical?

A: Yes. Both parts use the SOT-23-3 package (also designated TO-236 or SC-59) in surface mount configuration. They are mechanically and pin-compatible.

Q: What is the temperature range difference?

A: The MMBZ5259B-TP operates from -55°C to 150°C, while the MMBZ5259BLT1G extends the lower limit to -65°C. Both maintain the same 150°C upper limit.

Q: Are both parts RoHS3 compliant?

A: Yes. Both MMBZ5259B-TP and MMBZ5259BLT1G are RoHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements.

Q: Can these parts be used interchangeably in PCB assembly?

A: Yes, from a mechanical and footprint perspective. Electrical interchangeability depends on the circuit's power dissipation requirements. If power dissipation exceeds 225 mW, only the MMBZ5259B-TP is suitable.

Q: What is the base product number for both parts?

A: Both parts share the base product number MMBZ5259, indicating they are variants of the same zener diode design with different power ratings and temperature specifications.

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