MMBZ5221B Equivalent & Substitute Parts

Part Overview

The MMBZ5221B is a Zener diode manufactured by onsemi, rated at 2.4 V nominal with 350 mW maximum power dissipation in a surface mount SOT-23-3 package. This component is classified as obsolete, necessitating identification of equivalent and substitute parts for ongoing design requirements and procurement needs. The part operates across a temperature range of -55°C to 150°C with ±5% voltage tolerance and is suitable for voltage regulation and protection applications in electronic circuits.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	2.4	V
Tolerance	±5%	—
Power - Maximum	350	mW
Impedance (Maximum)	30	Ohms
Current - Reverse Leakage @ Vr	100	µA @ 1 V
Voltage - Forward (Maximum) @ 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	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the MMBZ5221B is determined by the following critical parameters:

Primary Matching Criteria:

Zener voltage: 2.4 V nominal
Package type: SOT-23-3 (TO-236-3, SC-59)
Mounting type: Surface Mount
Operating temperature range compatibility
Voltage tolerance specification

Secondary Compatibility Factors:

Maximum power dissipation (350 mW or higher)
Maximum impedance (30 Ohms or lower)
Reverse leakage current (100 µA @ 1 V or lower)
Forward voltage drop (900 mV @ 10 mA or lower)

Substitute parts are grouped into three categories based on their relationship to the main part:

Similar Parts (Lower Power Rating): Parts with identical zener voltage and package but reduced power ratings (225 mW) and extended temperature ranges (-65°C to 150°C). These are suitable for applications where the full 350 mW capability is not required.
Direct Equivalents (Matching Power Rating): Parts from alternative manufacturers with identical or equivalent electrical specifications, including 350 mW power rating and matching impedance characteristics.
Upgraded/Alternative Parts (Enhanced Specifications): Parts with tighter voltage tolerance (±1% to ±2%), automotive qualification (AEC-Q101), or enhanced performance characteristics while maintaining core functional compatibility.

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ohms)	Temp Range (°C)	Status	Package
MMBZ5221B	onsemi	2.4	±5%	350	30	-55 to 150	Obsolete	SOT-23-3
MMBZ5221BLT1G	onsemi	2.4	±5%	225	30	-65 to 150	Active	SOT-23-3
SZMMBZ5221BLT1G	onsemi	2.4	±5%	225	30	-65 to 150	Active	SOT-23-3
BZX84C2V4-TP	Micro Commercial Co	2.4	±5%	350	100	-55 to 150	Active	SOT-23-3
CMPZ5221B BK PBFREE	Central Semiconductor Corp	2.4	±5%	350	30	-65 to 150	Active	SOT-23-3
CMPZ5221B TR PBFREE	Central Semiconductor Corp	2.4	±5%	350	30	-65 to 150	Active	SOT-23-3
MMBZ5221B-7-F	Diodes Incorporated	2.4	±5%	350	30	-65 to 150	Active	SOT-23-3
BZX84-A2V4,215	NXP USA Inc.	2.4	±1%	250	100	-65 to 150	Active	SOT-23-3
BZX84-A2V4,235	NXP USA Inc.	2.4	±1%	250	100	-65 to 150	Active	SOT-23-3
BZX84B2V4-G3-08	Vishay General Semiconductor	2.4	±2%	300	100	-55 to 150	Active	SOT-23-3
BZX84B2V4-G3-18	Vishay General Semiconductor	2.4	±2%	300	100	-55 to 150	Active	SOT-23-3

Engineering Selection Recommendations

Primary Substitutes (Direct Replacement):

The CMPZ5221B TR PBFREE (Central Semiconductor Corp) and MMBZ5221B-7-F (Diodes Incorporated) are the most direct substitutes for the obsolete MMBZ5221B. Both parts maintain identical electrical specifications: 2.4 V nominal zener voltage, ±5% tolerance, 350 mW power rating, and 30 Ohms maximum impedance. Both are RoHS3 compliant and currently in active production status with substantial inventory availability. The MMBZ5221B-7-F offers extended temperature range (-65°C to 150°C) compared to the original part (-55°C to 150°C).

Secondary Substitutes (Reduced Power Rating):

The MMBZ5221BLT1G and SZMMBZ5221BLT1G (both onsemi) are suitable for applications where 225 mW power dissipation is sufficient. These parts maintain the same zener voltage, tolerance, and impedance specifications while providing extended temperature range (-65°C to 150°C). The SZMMBZ5221BLT1G includes automotive qualification (AEC-Q101), making it appropriate for automotive applications.

Alternative Substitutes (Different Impedance):

The BZX84C2V4-TP (Micro Commercial Co) provides identical power rating (350 mW) and zener voltage but features higher impedance (100 Ohms versus 30 Ohms). This part is suitable for applications where impedance variation is acceptable within circuit design margins.

Enhanced Specification Alternatives:

The BZX84-A2V4,215 and BZX84-A2V4,235 (NXP USA Inc.) offer tighter voltage tolerance (±1% versus ±5%) and automotive qualification (AEC-Q101). These parts are appropriate for precision voltage regulation applications requiring enhanced accuracy. The Vishay BZX84B2V4-G3-08 and BZX84B2V4-G3-18 provide ±2% tolerance and 300 mW power rating with automotive qualification.

Compliance Considerations:

All recommended substitutes are RoHS3 compliant and REACH unaffected. Parts designated with automotive qualification (AEC-Q101) are suitable for automotive applications requiring enhanced reliability standards.

Frequently Asked Questions (FAQ)

Q: Can MMBZ5221BLT1G replace MMBZ5221B in all applications?

A: The MMBZ5221BLT1G is electrically compatible for applications where 225 mW power dissipation is sufficient. If the circuit requires the full 350 mW capability, this part is not suitable. Both parts share identical zener voltage (2.4 V), tolerance (±5%), impedance (30 Ohms), and package (SOT-23-3).

Q: What is the difference between CMPZ5221B BK PBFREE and CMPZ5221B TR PBFREE?

A: Both parts are electrically identical with matching specifications. The difference is packaging: "BK" indicates Bulk packaging, while "TR" indicates Tape & Reel packaging. Selection depends on procurement and assembly requirements. The TR variant is typically preferred for automated assembly processes.

Q: Are NXP BZX84-A2V4 parts direct replacements?

A: The BZX84-A2V4 series maintains the 2.4 V zener voltage and SOT-23-3 package but differs in three parameters: tighter tolerance (±1% versus ±5%), lower power rating (250 mW versus 350 mW), and higher impedance (100 Ohms versus 30 Ohms). These parts are suitable for precision applications where the reduced power rating is acceptable.

Q: What does AEC-Q101 qualification mean?

A: AEC-Q101 is an automotive qualification standard indicating the component meets enhanced reliability and quality requirements for automotive applications. Parts with this qualification (SZMMBZ5221BLT1G, BZX84-A2V4 series, BZX84B2V4-G3 series) are suitable for automotive use.

Q: Can I use BZX84C2V4-TP as a direct replacement?

A: The BZX84C2V4-TP maintains the 2.4 V zener voltage, ±5% tolerance, 350 mW power rating, and SOT-23-3 package. However, it has higher impedance (100 Ohms versus 30 Ohms). This part is compatible if circuit design tolerates the impedance difference.

Q: Why do some parts have extended temperature range (-65°C to 150°C) versus the original (-55°C to 150°C)?

A: Extended lower temperature range indicates the part is qualified for operation at lower temperatures. This is a performance enhancement that does not affect compatibility with designs using the original temperature range. Parts with extended range are suitable as direct replacements.

Q: What is the significance of impedance (Zzt) differences?

A: Impedance affects the zener diode's dynamic resistance and voltage regulation characteristics. Lower impedance (30 Ohms) provides better voltage regulation stability. Higher impedance (100 Ohms) may result in slightly greater voltage variation under load changes. Selection depends on circuit regulation requirements.

Q: Are all substitute parts RoHS3 compliant?

A: All recommended substitute parts listed are RoHS3 compliant, ensuring compatibility with environmental and regulatory requirements for electronic components.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message