MMBZ5251B_D87Z Equivalent & Substitute Parts

Part Overview

The MMBZ5251B_D87Z is a 22 V Zener diode rated for 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.

Substiute Parts

MMBZ5251B_D87Z

onsemiIn Stock: 860MMBZ5251B_D87Z Datasheet

Current PartRFQ

MMBZ5251BLT1G

onsemiIn Stock: 8218MMBZ5251BLT1G Datasheet

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MMBZ5251B-7-F

Diodes IncorporatedIn Stock: 4424MMBZ5251B-7-F Datasheet

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BZX84B22-TP

Micro Commercial CoIn Stock: 1225BZX84B22-TP Datasheet

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BZX84C22-TP

Micro Commercial CoIn Stock: 1154BZX84C22-TP Datasheet

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CZRT5251B-G

Comchip TechnologyIn Stock: 1106CZRT5251B-G Datasheet

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CZRT55C22-G

Comchip TechnologyIn Stock: 972CZRT55C22-G Datasheet

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MMBZ5251B-TP

Micro Commercial CoIn Stock: 1181MMBZ5251B-TP Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the MMBZ5251B_D87Z is determined by the following critical parameters:

Primary Substitution Criteria:

• Zener voltage: 22 V nominal
• Tolerance: ±5% or tighter
• Power rating: 350 mW or greater
• Impedance: 29 Ohms or lower
• Reverse leakage: 100 nA @ 17 V or lower
• Forward voltage: 900 mV @ 10 mA or lower
• Package: SOT-23-3 (TO-236-3, SC-59)
• Mounting: Surface Mount

Substitution Categories:

Category A - Direct Equivalents (All parameters match or exceed specifications): Parts that maintain identical electrical specifications and impedance characteristics, suitable for direct replacement without circuit redesign.

Category B - Functional Equivalents (Core parameters match; minor parameter variations): Parts that maintain the 22 V zener voltage and 350 mW power rating but may have higher impedance or different tolerance specifications. These require verification of circuit performance under specific application conditions.

Category C - Reduced Power Alternatives (Lower power rating): Parts rated for 225 mW or 300 mW maximum power. These are suitable only for applications where the circuit design permits reduced power dissipation.

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation - Category A (Direct Equivalents):

MMBZ5251B-7-F (Diodes Incorporated) is the preferred direct substitute. This part maintains identical electrical specifications to the MMBZ5251B_D87Z, including 22 V nominal zener voltage, ±5% tolerance, 350 mW power rating, and 29 Ohms maximum impedance. The part is active with ROHS3 compliance and offers an extended operating temperature range (-65°C to 150°C). Tape & Reel packaging ensures compatibility with automated assembly processes.

MMBZ5251B-TP (Micro Commercial Co) provides an alternative direct equivalent with identical electrical parameters and matching temperature range to the original part (-55°C to 150°C). This part is active and ROHS3 compliant, suitable for direct replacement in existing designs.

Secondary Recommendation - Category B (Functional Equivalents with Higher Impedance):

BZX84C22-TP and BZX84B22-TP (Micro Commercial Co) maintain the 22 V zener voltage and 350 mW power rating but feature 55 Ohms maximum impedance compared to 29 Ohms in the original part. BZX84B22-TP offers tighter tolerance (±2%) at the cost of higher impedance. These parts are suitable for applications where impedance variation does not affect circuit performance. Both are active and ROHS3 compliant.

CZRT55C22-G (Comchip Technology) provides 350 mW power rating with 55 Ohms impedance and ±6% tolerance. This part is active with ROHS3 compliance and extended temperature range (-65°C to 150°C).

Tertiary Recommendation - Category C (Reduced Power Alternatives):

MMBZ5251BLT1G (onsemi) is rated for 225 mW maximum power with 29 Ohms impedance and ±5% tolerance. This part is active and suitable only for applications where circuit design permits reduced power dissipation. Extended temperature range (-65°C to 150°C) is available.

CZRT5251B-G (Comchip Technology) is rated for 300 mW maximum power with 29 Ohms impedance and ±5% tolerance. This part is active with ROHS3 compliance and extended temperature range (-65°C to 150°C).

All recommended substitutes are available in surface mount SOT-23-3 packaging and maintain forward voltage characteristics of 900 mV @ 10 mA.

Frequently Asked Questions (FAQ)

Q: Can MMBZ5251B-7-F be used as a direct replacement for MMBZ5251B_D87Z?

A: Yes. MMBZ5251B-7-F maintains identical electrical specifications including 22 V zener voltage, ±5% tolerance, 350 mW power rating, and 29 Ohms maximum impedance. The part is active with current manufacturing support and ROHS3 compliance. The extended operating temperature range (-65°C to 150°C) provides additional margin compared to the original part (-55°C to 150°C).

Q: What is the difference between parts with 29 Ohms and 55 Ohms impedance?

A: Impedance (Zzt) affects the dynamic resistance of the zener diode. Lower impedance (29 Ohms) provides better voltage regulation with reduced voltage variation across the operating current range. Higher impedance (55 Ohms) results in greater voltage variation but may be acceptable in applications with less stringent regulation requirements. Circuit performance must be evaluated based on specific application demands.

Q: Are the reduced power alternatives (225 mW and 300 mW) suitable for all applications?

A: No. Reduced power alternatives are suitable only for applications where the circuit design permits lower power dissipation. If the original design requires 350 mW capability, reduced power alternatives may cause thermal stress or circuit malfunction. Verify that the application circuit does not exceed the lower power rating under worst-case operating conditions.

Q: What is the significance of tolerance differences (±2%, ±5%, ±6%)?

A: Tolerance specifies the allowable deviation from the nominal 22 V zener voltage. Tighter tolerance (±2%) ensures more precise voltage regulation but may have limited availability. Standard tolerance (±5%) provides adequate precision for most applications. Wider tolerance (±6%) may be acceptable in applications with less stringent voltage regulation requirements. Select tolerance based on circuit design specifications.

Q: Are all substitute parts ROHS3 compliant?

A: Most active substitute parts listed are ROHS3 compliant. MMBZ5251BLT1G, CZRT5251B-G, CZRT55C22-G, BZX84C22-TP, and MMBZ5251B-7-F are confirmed ROHS3 compliant. MMBZ5251B-TP compliance status is confirmed as ROHS3. Verify compliance documentation for specific procurement requirements.

Q: What packaging options are available for these substitutes?

A: All substitute parts are available in SOT-23-3 surface mount package (also designated TO-236-3 or SC-59). Packaging formats vary by manufacturer: Tape & Reel (TR) for automated assembly, Bulk for manual assembly, and standard packaging. Select packaging format based on assembly process requirements.

Q: Can parts with different temperature ranges be used interchangeably?

A: Temperature range interchangeability depends on the application environment. The original part operates from -55°C to 150°C. Substitute parts with extended range (-65°C to 150°C) provide additional margin for low-temperature operation. Parts with identical or extended temperature ranges are suitable for direct substitution. Verify that the application environment does not exceed the specified temperature range of the selected substitute.

Q: What is the reverse leakage current specification?

A: Reverse leakage current (100 nA @ 17 V for most parts) specifies the maximum current flowing through the diode in reverse bias condition. Lower leakage current indicates better diode quality and reduced power loss in standby conditions. All listed substitutes maintain the 100 nA specification at their respective reverse voltage test points.