MMBZ5240B-7 Equivalent & Substitute Parts

Part Overview

The MMBZ5240B-7 is a 10 V Zener diode rated at 350 mW in a surface mount SOT-23-3 package, manufactured by Diodes Incorporated. This component is discontinued at DiGi Electronics, necessitating identification of equivalent and substitute parts for ongoing design requirements and production needs. Equivalent parts maintain identical electrical and mechanical specifications, while substitute parts provide functional alternatives within acceptable parameter tolerances for 10 V Zener diode applications.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	10	V
Tolerance	±5%	—
Power - Max	350	mW
Impedance (Max)	17	Ohms
Current - Reverse Leakage @ Vr	3	µA @ 8 V
Voltage - Forward (Vf) (Max) @ If	900	mV @ 10 mA
Operating Temperature	-65 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	TO-236-3, SC-59, SOT-23-3	—

Substitute Part Grouping Explanation

Substitution of the MMBZ5240B-7 is determined by the following critical parameters:

Primary Substitution Criteria:

Zener voltage: 10 V nominal
Package compatibility: SOT-23-3 / TO-236-3 / SC-59 surface mount
Operating temperature range: minimum -65°C to 150°C
Voltage tolerance: ±5% or better
Forward voltage: 900 mV maximum @ 10 mA

Secondary Substitution Considerations:

Power dissipation rating: 350 mW (primary specification) or 225 mW (reduced rating acceptable for lower-power applications)
Impedance: 17 to 20 Ohms maximum
Reverse leakage current: 3 µA @ 8 V or lower

Substitute parts are grouped into two categories: Parametric Equivalents (matching all primary specifications) and Manufacturer Recommended Alternatives (meeting functional requirements with acceptable parameter variations).

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ω)	Ir @ Vr (µA)	Vf (mV)	Temp Range (°C)	Package	RoHS Status
MMBZ5240B-7	Diodes Incorporated	10	±5%	350	17	3 @ 8V	900 @ 10mA	-65 to 150	SOT-23-3	Non-compliant
MMBZ5240B-7-F	Diodes Incorporated	10	±5%	350	17	3 @ 8V	900 @ 10mA	-65 to 150	SOT-23-3	ROHS3 Compliant
BZX84-A10,215	Nexperia USA Inc.	10	±1%	250	20	200 nA @ 7V	900 @ 10mA	-65 to 150	TO-236AB	ROHS3 Compliant
BZX84C10-TP	Micro Commercial Co	10	±5%	350	20	200 nA @ 7V	900 @ 10mA	-55 to 150	SOT-23	ROHS3 Compliant
MMBZ5240BLT1G	onsemi	10	±5%	225	17	3 @ 8V	900 @ 10mA	-65 to 150	SOT-23-3	ROHS3 Compliant
SZMMBZ5240BLT1G	onsemi	10	±5%	225	17	3 @ 8V	900 @ 10mA	-65 to 150	SOT-23-3	ROHS3 Compliant
SZMMBZ5240ELT1G	onsemi	10	±5%	225	17	3 @ 8V	900 @ 10mA	-55 to 150	SOT-23-3	ROHS3 Compliant
CMPZ5240B TR PBFREE	Central Semiconductor Corp	10	±5%	350	17	3 @ 8V	900 @ 10mA	-65 to 150	SOT-23	ROHS3 Compliant

Engineering Selection Recommendations

Direct Parametric Equivalent (Recommended Primary Substitute):

MMBZ5240B-7-F from Diodes Incorporated is the direct equivalent, matching all electrical and mechanical specifications of the original part. This part is currently active and ROHS3 compliant, making it the preferred replacement for discontinued MMBZ5240B-7 applications.

Full-Specification Alternatives:

CMPZ5240B TR PBFREE from Central Semiconductor Corp provides identical electrical performance (10 V, 350 mW, ±5% tolerance, 17 Ω impedance) with ROHS3 compliance and active product status. This part is suitable for direct substitution in applications requiring the full 350 mW power rating.

Reduced Power Rating Alternatives:

MMBZ5240BLT1G and SZMMBZ5240BLT1G from onsemi provide 225 mW power dissipation with identical 10 V nominal voltage, ±5% tolerance, and 17 Ω impedance. These parts are suitable for applications where power dissipation does not exceed 225 mW. SZMMBZ5240BLT1G includes AEC-Q101 automotive qualification.

SZMMBZ5240ELT1G from onsemi offers the same 225 mW rating with AEC-Q101 automotive qualification and operating temperature range of -55°C to 150°C. This part is appropriate for automotive applications with reduced low-temperature requirements.

Precision Tolerance Alternative:

BZX84-A10,215 from Nexperia USA Inc. provides superior voltage tolerance (±1% versus ±5%), lower reverse leakage current (200 nA @ 7 V), and AEC-Q101 automotive qualification. Power rating is 250 mW, suitable for applications not requiring the full 350 mW specification. Operating temperature range matches the original part (-65°C to 150°C).

Equivalent Power Rating Alternative:

BZX84C10-TP from Micro Commercial Co maintains the 350 mW power rating with ±5% tolerance and 20 Ω impedance. Operating temperature range is -55°C to 150°C. This part is suitable for applications where the lower temperature limit of -55°C is acceptable.

Frequently Asked Questions (FAQ)

Q: Can MMBZ5240B-7-F be used as a direct replacement for MMBZ5240B-7?

A: Yes. MMBZ5240B-7-F is a parametric equivalent with identical electrical specifications (10 V, 350 mW, ±5%, 17 Ω) and package (SOT-23-3). The primary difference is ROHS3 compliance and active product status. This is the recommended replacement.

Q: What is the difference between the onsemi parts (MMBZ5240BLT1G, SZMMBZ5240BLT1G, SZMMBZ5240ELT1G)?

A: All three onsemi parts share the same 10 V nominal voltage, ±5% tolerance, and 17 Ω impedance. MMBZ5240BLT1G is supplied in Cut Tape & Digi-Reel packaging. SZMMBZ5240BLT1G and SZMMBZ5240ELT1G are supplied in Tape & Reel packaging and include AEC-Q101 automotive qualification. SZMMBZ5240ELT1G has a reduced operating temperature range (-55°C to 150°C) compared to the other two (-65°C to 150°C). All three have 225 mW power rating versus the original 350 mW.

Q: Can I use a 225 mW part instead of the 350 mW original?

A: Yes, if your application's actual power dissipation does not exceed 225 mW. The 225 mW rating is a maximum specification; parts with lower ratings can be used in applications with lower power requirements. Verify that your circuit design does not require the full 350 mW capability.

Q: What is the significance of the ±1% tolerance on BZX84-A10,215 compared to ±5% on other parts?

A: The ±1% tolerance on BZX84-A10,215 provides tighter voltage regulation, resulting in more precise 10 V output. This is beneficial for applications requiring strict voltage accuracy. However, the 250 mW power rating is lower than the original 350 mW specification.

Q: Are the automotive-qualified parts (SZMMBZ5240BLT1G, SZMMBZ5240ELT1G, BZX84-A10,215) suitable for non-automotive applications?

A: Yes. AEC-Q101 qualification indicates automotive-grade reliability and testing. These parts exceed standard requirements and are suitable for any application, including non-automotive designs requiring high reliability.

Q: What is the difference between SOT-23-3 and TO-236AB packaging?

A: SOT-23-3 and TO-236AB are equivalent package designations for the same physical form factor. Both refer to a three-terminal surface mount package with identical pin configuration and footprint. Parts specified as either SOT-23-3 or TO-236AB are mechanically and electrically interchangeable.

Q: Why does BZX84C10-TP have a -55°C minimum operating temperature instead of -65°C?

A: Operating temperature range is a specification set by the manufacturer. BZX84C10-TP is rated for -55°C to 150°C, while the original MMBZ5240B-7 is rated for -65°C to 150°C. If your application requires operation below -55°C, BZX84C10-TP is not suitable; select an alternative with -65°C minimum rating.

Q: What does ROHS3 compliance mean?

A: ROHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting lead and other hazardous materials. The original MMBZ5240B-7 is non-compliant; all substitute parts listed are ROHS3 compliant, making them suitable for modern manufacturing and environmental standards.

Q: Can I mix different substitute parts in the same design?

A: Yes, provided all parts meet your application's electrical requirements. However, for consistency in manufacturing and testing, using a single part number across a design is recommended. If mixing is necessary, verify that all selected parts operate within the same voltage tolerance and power dissipation range.

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