MMBZ5252B_D87Z Zener Diode 24V 350mW SOT-23-3 Equivalent & Substitute Parts

Part Overview

The MMBZ5252B_D87Z is a 24V Zener diode manufactured by onsemi, rated for 350mW power dissipation in a surface mount SOT-23-3 package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. 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)	24	V
Tolerance	±5%	%
Power - Maximum	350	mW
Impedance (Maximum)	33	Ohms
Current - Reverse Leakage @ Vr	100 nA @ 18V	nA
Voltage - Forward (Maximum) @ If	900 mV @ 10 mA	mV
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	SOT-23-3 (TO-236-3, SC-59)	—

Substitute Part Grouping Explanation

Substitution eligibility for the MMBZ5252B_D87Z is determined by the following critical parameters:

Primary Substitution Criteria:

Zener voltage: 24V nominal
Voltage tolerance: ±5% or tighter
Power rating: 350mW or greater
Package: SOT-23-3 surface mount
Impedance: 33 Ohms or lower
Reverse leakage: 100nA @ 18V or lower
Forward voltage: 900mV @ 10mA or lower
Operating temperature: -55°C to 150°C minimum

Substitute Categories:

Direct Equivalents (Active Status): Parts meeting all primary criteria with identical or superior electrical specifications and active product status. These include MMBZ5252B-7-F (Diodes Incorporated), MMBZ5252BLT1G (onsemi), and MMBZ5252B-TP (Micro Commercial Co).

Compatible Alternatives (Parametric Equivalents): Parts with matching zener voltage and power rating but minor variations in secondary parameters such as impedance or tolerance. These include BZX84C24-TP and CZRT5252B-G.

Functional Substitutes (Similar Performance): Parts with 24V zener voltage and 350mW power rating but with tolerance or impedance variations that remain within acceptable application ranges. These include CZRT55C24-G and BZX84B24-TP.

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ω)	Temp Range (°C)	Status	Package
MMBZ5252B_D87Z	onsemi	24	±5%	350	33	-55 to 150	Obsolete	SOT-23-3
MMBZ5252B-7-F	Diodes Incorporated	24	±5%	350	33	-65 to 150	Active	SOT-23-3
MMBZ5252BLT1G	onsemi	24	±5%	225	33	-65 to 150	Active	SOT-23-3
MMBZ5252BQ-7-F	Diodes Incorporated	24	±5%	350	33	-65 to 150	Active	SOT-23-3
MMBZ5252B-TP	Micro Commercial Co	24	±5%	350	33	-55 to 150	Active	SOT-23-3
BZX84C24-TP	Micro Commercial Co	24	±5%	350	70	-55 to 150	Active	SOT-23-3
BZX84B24-TP	Micro Commercial Co	24	±2%	350	70	-55 to 150	Active	SOT-23-3
CZRT5252B-G	Comchip Technology	24	±5%	300	33	-65 to 150	Active	SOT-23-3
CZRT55C24-G	Comchip Technology	24	±6%	350	70	-65 to 150	Active	SOT-23-3

Engineering Selection Recommendations

Preferred Direct Replacements:

MMBZ5252B-7-F (Diodes Incorporated) and MMBZ5252B-TP (Micro Commercial Co) are the primary recommended substitutes. Both parts are active products with identical electrical specifications to the original MMBZ5252B_D87Z, including 24V zener voltage, ±5% tolerance, 350mW power rating, and 33 Ohm impedance. MMBZ5252B-7-F offers an extended lower operating temperature limit (-65°C vs -55°C) and RoHS3 compliance. MMBZ5252B-TP maintains the original temperature range and provides equivalent performance.

Secondary Alternatives:

MMBZ5252BQ-7-F (Diodes Incorporated) is suitable for automotive applications, carrying AEC-Q101 qualification and RoHS3 compliance. This part is recommended when automotive-grade reliability is required.

MMBZ5252BLT1G (onsemi) is an active product from the original manufacturer but with reduced power rating (225mW vs 350mW). This part is suitable only for applications where the lower power dissipation is acceptable.

Compatible Alternatives with Parameter Variations:

BZX84C24-TP (Micro Commercial Co) maintains 350mW power rating and ±5% tolerance but features 70 Ohm impedance (vs 33 Ohm). This higher impedance may affect voltage regulation characteristics in sensitive applications.

CZRT5252B-G (Comchip Technology) provides 300mW power rating with 33 Ohm impedance and ±5% tolerance. This part is suitable for applications where 300mW power dissipation is sufficient.

CZRT55C24-G (Comchip Technology) offers 350mW power rating but with ±6% tolerance and 70 Ohm impedance. This part is acceptable where tolerance relaxation is permissible.

BZX84B24-TP (Micro Commercial Co) provides tighter ±2% tolerance with 350mW power rating but features 70 Ohm impedance. This part is recommended for applications requiring improved voltage accuracy.

Compliance Considerations:

All recommended active substitutes carry RoHS3 compliance and REACH Unaffected status, matching the regulatory profile of the original part. Moisture sensitivity level remains at MSL 1 (Unlimited) across all substitutes.

Frequently Asked Questions (FAQ)

Q: Can MMBZ5252BLT1G replace MMBZ5252B_D87Z directly?

A: MMBZ5252BLT1G is electrically compatible but has reduced power rating (225mW vs 350mW). Direct replacement is possible only if the application's power dissipation requirement does not exceed 225mW. For applications requiring full 350mW capability, use MMBZ5252B-7-F or MMBZ5252B-TP instead.

Q: What is the difference between MMBZ5252B-7-F and MMBZ5252B-TP?

A: Both parts are parametric equivalents with identical electrical specifications (24V, ±5%, 350mW, 33Ω). MMBZ5252B-7-F is manufactured by Diodes Incorporated with extended temperature range (-65°C to 150°C), while MMBZ5252B-TP is manufactured by Micro Commercial Co with the original temperature range (-55°C to 150°C). Selection depends on temperature requirements and supplier availability.

Q: Why do BZX84C24-TP and CZRT55C24-G have higher impedance (70Ω)?

A: Impedance variation reflects different manufacturing processes and die designs. Higher impedance (70Ω vs 33Ω) results in slightly different voltage regulation characteristics. These parts remain functionally compatible but may exhibit different dynamic response in voltage regulation circuits. Verify impedance compatibility with circuit design requirements before substitution.

Q: Is MMBZ5252BQ-7-F suitable for non-automotive applications?

A: Yes. MMBZ5252BQ-7-F meets automotive qualification (AEC-Q101) but is not restricted to automotive use. It provides superior reliability margins and is suitable for any application where the electrical specifications match requirements. The automotive qualification represents an additional quality assurance level.

Q: Can I use BZX84B24-TP for improved voltage accuracy?

A: BZX84B24-TP offers ±2% tolerance (vs ±5% on the original part), providing tighter voltage regulation. However, it features 70Ω impedance instead of 33Ω. Use this part only if both tighter tolerance and higher impedance are acceptable for the application. Verify circuit performance before production implementation.

Q: Are all substitute parts available in the same packaging format?

A: All listed substitutes use SOT-23-3 surface mount package, maintaining mechanical compatibility. Packaging format variations (Tape & Reel vs Bulk) affect procurement and handling but not electrical or mechanical fit. Confirm packaging availability with suppliers based on production volume requirements.

Q: What is the impact of ±6% tolerance in CZRT55C24-G?

A: CZRT55C24-G tolerance of ±6% is wider than the original ±5%. This means the actual zener voltage may vary between 22.56V and 25.44V (vs 22.8V to 25.2V for ±5%). Use this part only in applications where the wider tolerance band is acceptable. Verify voltage regulation performance in circuit simulation before substitution.

Q: Should I prioritize active status when selecting a substitute?

A: Yes. Active product status ensures ongoing availability, manufacturing consistency, and supplier support. All recommended primary substitutes (MMBZ5252B-7-F, MMBZ5252B-TP, MMBZ5252BQ-7-F) are active products. The original MMBZ5252B_D87Z is obsolete, making active substitutes essential for long-term design support.

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