MMBZ5221B-7 Zener Diode Equivalent & Substitute Parts

Part Overview

The MMBZ5221B-7 is a 2.4 V zener diode manufactured by Diodes Incorporated, rated for 350 mW power dissipation in a surface mount SOT-23-3 package. This part is discontinued at DiGi Electronics, making equivalent and substitute parts necessary for ongoing design support and procurement. The device operates across a temperature range of -65°C to 150°C 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	-65 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	SOT-23-3 (TO-236-3, SC-59)	—

Substitute Part Grouping Explanation

Substitution of the MMBZ5221B-7 is determined by the following critical parameters:

Primary Substitution Criteria:

Zener voltage (Vz): 2.4 V nominal
Package type: SOT-23-3 surface mount
Operating temperature range: -65°C to 150°C
Forward voltage (Vf): 900 mV @ 10 mA

Secondary Substitution Criteria:

Power rating: 350 mW (primary), 250 mW (acceptable for lower power applications), 225 mW (acceptable for lower power applications)
Tolerance: ±5% (primary), ±2% (tighter tolerance acceptable), ±1% (tighter tolerance acceptable)
Impedance: 30 Ohms (primary), 100 Ohms (acceptable for different circuit requirements)
Reverse leakage current: 100 µA @ 1 V (primary), 50 µA @ 1 V (lower leakage acceptable)

Substitute parts are grouped into three categories:

Category 1: Direct Manufacturer Equivalents (Diodes Incorporated) Parts with identical electrical specifications and packaging from the same manufacturer.

Category 2: Manufacturer Recommended Substitutes (NXP/Nexperia and onsemi) Parts with matching zener voltage and package, with variations in power rating, tolerance, or impedance. These parts meet automotive qualification standards where applicable.

Category 3: Parametric Equivalents (Central Semiconductor Corp) Parts with matching core electrical specifications and packaging from alternative manufacturers.

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ohms)	Reverse Leakage (µA @ 1V)	Vf (mV @ 10mA)	Package	Product Status
MMBZ5221B-7	Diodes Incorporated	2.4	±5%	350	30	100	900	SOT-23-3	Discontinued
MMBZ5221B-7-F	Diodes Incorporated	2.4	±5%	350	30	100	900	SOT-23-3	Active
CMPZ5221B TR PBFREE	Central Semiconductor Corp	2.4	±5%	350	30	100	900	SOT-23-3	Active
BZX84-A2V4,215	NXP USA Inc.	2.4	±1%	250	100	50	900	SOT-23-3	Active
BZX84-A2V4,235	NXP USA Inc.	2.4	±1%	250	100	50	900	SOT-23-3	Active
BZX84-B2V4,215	Nexperia USA Inc.	2.4	±2%	250	100	50	900	SOT-23-3	Active
MMBZ5221BLT1G	onsemi	2.4	±5%	225	30	100	900	SOT-23-3	Active
SZMMBZ5221BLT1G	onsemi	2.4	±5%	225	30	100	900	SOT-23-3	Active

Engineering Selection Recommendations

First Priority: MMBZ5221B-7-F (Diodes Incorporated)

This part is the direct equivalent of the discontinued MMBZ5221B-7, offering identical electrical specifications and packaging. It is manufactured by the same supplier and maintains full compatibility with existing designs. Product status is Active with high inventory availability (18,580 pcs). RoHS3 compliance is confirmed.

Second Priority: CMPZ5221B TR PBFREE (Central Semiconductor Corp)

This parametric equivalent provides identical electrical specifications (350 mW, ±5% tolerance, 30 Ohms impedance) and SOT-23-3 packaging. Product status is Active with adequate inventory (5,452 pcs). RoHS3 compliance is confirmed. Selection of this part requires verification of supplier qualification within your procurement system.

Third Priority: MMBZ5221BLT1G or SZMMBZ5221BLT1G (onsemi)

These parts are suitable for applications where power dissipation can be reduced to 225 mW. Both maintain the 2.4 V zener voltage, ±5% tolerance, and 30 Ohms impedance. SZMMBZ5221BLT1G includes AEC-Q101 automotive qualification. Product status is Active with high inventory availability (65,200 pcs and 33,300 pcs respectively). RoHS3 compliance is confirmed.

Alternative for Automotive Applications: BZX84-A2V4,215 or BZX84-B2V4,215 (NXP/Nexperia)

These parts are qualified to AEC-Q101 automotive standards and provide tighter tolerance specifications (±1% and ±2% respectively). Power rating is reduced to 250 mW, and impedance is increased to 100 Ohms. These characteristics are suitable for automotive voltage regulation circuits where higher precision is required. Product status is Active with adequate inventory availability.

Compliance Considerations:

All substitute parts listed are RoHS3 compliant and REACH unaffected. The original MMBZ5221B-7 is RoHS non-compliant; substitution with any listed part introduces RoHS3 compliance to the design.

Frequently Asked Questions (FAQ)

Q: Can MMBZ5221B-7-F be used as a direct replacement for MMBZ5221B-7?

A: Yes. MMBZ5221B-7-F is the direct equivalent with identical electrical specifications (2.4 V, 350 mW, ±5%, 30 Ohms) and SOT-23-3 packaging. The primary difference is packaging format (Tape & Reel vs. bulk) and product status (Active vs. Discontinued).

Q: What is the difference between MMBZ5221BLT1G and SZMMBZ5221BLT1G?

A: Both parts are manufactured by onsemi with identical electrical specifications (2.4 V, 225 mW, ±5%, 30 Ohms). SZMMBZ5221BLT1G includes AEC-Q101 automotive qualification, while MMBZ5221BLT1G does not. Packaging differs (Cut Tape & Digi-Reel vs. Tape & Reel).

Q: Can I use BZX84-A2V4,215 in place of MMBZ5221B-7?

A: Substitution is possible if circuit design accommodates the following differences: reduced power rating (250 mW vs. 350 mW), increased impedance (100 Ohms vs. 30 Ohms), lower reverse leakage (50 µA vs. 100 µA), and tighter tolerance (±1% vs. ±5%). The zener voltage (2.4 V) and forward voltage (900 mV @ 10 mA) are identical. This part is AEC-Q101 qualified for automotive applications.

Q: What does the "-7-F" suffix in MMBZ5221B-7-F indicate?

A: The "-7" suffix indicates the tape and reel packaging specification from Diodes Incorporated. The "-F" suffix indicates RoHS3 compliance and lead-free construction. This part is the active production equivalent of the discontinued MMBZ5221B-7.

Q: Are all substitute parts available in SOT-23-3 packaging?

A: Yes. All substitute parts listed are available in SOT-23-3 surface mount packaging (also designated as TO-236-3 or SC-59). This ensures mechanical and electrical compatibility with existing PCB layouts.

Q: Which substitute part has the lowest reverse leakage current?

A: BZX84-A2V4,215 and BZX84-A2V4,235 both specify 50 µA @ 1 V reverse leakage, compared to 100 µA @ 1 V for the original MMBZ5221B-7. This lower leakage may be beneficial in precision voltage reference applications.

Q: Can I use a substitute part with lower power rating (225 mW or 250 mW)?

A: Substitution with lower power ratings is permissible only if circuit analysis confirms that the maximum power dissipation in the zener diode does not exceed the substitute part's rating. Thermal management and circuit operating conditions must be evaluated.

Q: What is the difference between BZX84-A2V4,215 and BZX84-A2V4,235?

A: Both parts are manufactured by NXP USA Inc. with identical electrical specifications (2.4 V, 250 mW, ±1%, 100 Ohms). The primary difference is packaging format: BZX84-A2V4,215 is supplied in standard packaging, while BZX84-A2V4,235 is supplied in Bulk packaging.

Q: Are substitute parts with ±1% or ±2% tolerance backward compatible with designs specified for ±5%?

A: Yes. Tighter tolerance specifications (±1% or ±2%) are backward compatible with designs specified for ±5% tolerance. The substitute part will operate within the original design specification range.

Q: Which substitute part is recommended for new automotive designs?

A: SZMMBZ5221BLT1G or BZX84-B2V4,215 are recommended for automotive applications. SZMMBZ5221BLT1G maintains the original power rating (225 mW) and impedance (30 Ohms) with AEC-Q101 qualification. BZX84-B2V4,215 provides AEC-Q101 qualification with ±2% tolerance and 250 mW power rating.

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