MMBZ5245B Equivalent & Substitute Parts

Part Overview

The MMBZ5245B is a 15 V, 350 mW Zener diode manufactured by onsemi in SOT-23-3 surface mount packaging. This component is classified as obsolete, indicating discontinuation from the original manufacturer. Equivalent and substitute parts are necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this Zener diode specification.

Key Parameters

Parameter	Value
Voltage - Zener (Nom)	15 V
Tolerance	±5%
Power - Max	350 mW
Impedance (Max)	16 Ohms
Current - Reverse Leakage @ Vr	100 nA @ 11 V
Voltage - Forward (Vf) (Max) @ If	900 mV @ 10 mA
Operating Temperature	-55°C ~ 150°C
Mounting Type	Surface Mount
Package / Case	TO-236-3, SC-59, SOT-23-3

Substitute Part Grouping Explanation

Substitution of the MMBZ5245B is determined by electrical and mechanical parameter compatibility within the Zener diode category. The critical parameters governing substitution are:

Electrical Parameters:

Zener voltage: 15 V nominal
Tolerance: ±5%
Power dissipation: 350 mW maximum
Impedance: 16 Ohms maximum
Reverse leakage current: 100 nA @ 11 V
Forward voltage: 900 mV @ 10 mA

Mechanical Parameters:

Package type: SOT-23-3 (TO-236-3, SC-59)
Mounting: Surface mount

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

Similar Parts (Lower Power Rating): MMBZ5245BLT1G, MMBZ5245ELT1G, SZMMBZ5245BLT1G, and SZMMBZ5245ELT1G feature identical electrical specifications except for reduced maximum power dissipation (225 mW versus 350 mW). These parts maintain the same Zener voltage, tolerance, impedance, and reverse leakage characteristics. Some variants include automotive qualification (AEC-Q101) and extended temperature ranges.

Direct Equivalents (Matching Specifications): BZX84C15-TP, CMPZ5245B BK PBFREE, and CMPZ5245B TR PBFREE provide equivalent 15 V, 350 mW performance with identical package specifications. These parts are sourced from alternative manufacturers (Micro Commercial Co and Central Semiconductor Corp) and are currently in active production status.

Upgrade Parts (Active Production): MMBZ5245B-7-F and MMBZ5245BQ-7-F are manufactured by Diodes Incorporated and provide identical electrical and mechanical specifications to the original MMBZ5245B. The MMBZ5245BQ-7-F variant includes automotive-grade qualification (AEC-Q101) and extended operating temperature range (-65°C to 150°C).

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power Max	Zzt (Max)	Vf (Max) @ If	Temp Range	Package	Status
MMBZ5245B	onsemi	15 V	±5%	350 mW	16 Ω	900 mV @ 10 mA	-55°C ~ 150°C	SOT-23-3	Obsolete
MMBZ5245BLT1G	onsemi	15 V	±5%	225 mW	16 Ω	900 mV @ 10 mA	-65°C ~ 150°C	SOT-23-3	Active
MMBZ5245ELT1G	onsemi	15 V	±5%	225 mW	16 Ω	900 mV @ 10 mA	-55°C ~ 150°C	SOT-23-3	Active
SZMMBZ5245BLT1G	onsemi	15 V	±5%	225 mW	16 Ω	900 mV @ 10 mA	-65°C ~ 150°C	SOT-23-3	Active
SZMMBZ5245ELT1G	onsemi	15 V	—	225 mW	16 Ω	950 mV @ 10 mA	-65°C ~ 150°C	SOT-23-3	Active
BZX84C15-TP	Micro Commercial Co	15 V	±5%	350 mW	30 Ω	900 mV @ 10 mA	-55°C ~ 150°C	SOT-23-3	Active
CMPZ5245B BK PBFREE	Central Semiconductor Corp	15 V	±5%	350 mW	16 Ω	900 mV @ 10 mA	-65°C ~ 150°C	SOT-23-3	Active
CMPZ5245B TR PBFREE	Central Semiconductor Corp	15 V	±5%	350 mW	16 Ω	900 mV @ 10 mA	-65°C ~ 150°C	SOT-23-3	Active
MMBZ5245B-7-F	Diodes Incorporated	15 V	±5%	350 mW	16 Ω	900 mV @ 10 mA	-65°C ~ 150°C	SOT-23-3	Active
MMBZ5245BQ-7-F	Diodes Incorporated	15 V	±5%	350 mW	16 Ω	900 mV @ 10 mA	-65°C ~ 150°C	SOT-23-3	Active
BZX84B15-TP	Micro Commercial Co	15 V	±2%	350 mW	30 Ω	900 mV @ 10 mA	-55°C ~ 150°C	SOT-23-3	Active

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications):

MMBZ5245B-7-F (Diodes Incorporated) and MMBZ5245BQ-7-F (Diodes Incorporated) provide complete electrical and mechanical equivalence to the obsolete MMBZ5245B. Both parts are in active production status with RoHS3 compliance. MMBZ5245BQ-7-F includes automotive-grade qualification (AEC-Q101) and extended operating temperature range (-65°C to 150°C), making it suitable for automotive and industrial applications requiring enhanced reliability.

CMPZ5245B BK PBFREE and CMPZ5245B TR PBFREE (Central Semiconductor Corp) offer equivalent 15 V, 350 mW specifications with identical impedance characteristics (16 Ohms). Both variants are RoHS3 compliant and support extended temperature operation (-65°C to 150°C).

BZX84C15-TP (Micro Commercial Co) provides matching 15 V, 350 mW performance with RoHS3 compliance. This part features slightly higher impedance (30 Ohms versus 16 Ohms) and is suitable for applications where impedance variation is acceptable.

For Power-Constrained Applications:

MMBZ5245BLT1G, MMBZ5245ELT1G, SZMMBZ5245BLT1G, and SZMMBZ5245ELT1G are suitable substitutes when circuit design permits reduced power dissipation (225 mW versus 350 mW). All variants maintain 15 V Zener voltage, ±5% tolerance, and 16 Ohm impedance. SZMMBZ5245BLT1G and SZMMBZ5245ELT1G include automotive qualification (AEC-Q101).

For Tighter Voltage Tolerance:

BZX84B15-TP (Micro Commercial Co) provides ±2% tolerance compared to the ±5% specification of the MMBZ5245B. This part is applicable when circuit design requires improved voltage regulation accuracy.

Frequently Asked Questions (FAQ)

Q: Can MMBZ5245BLT1G be used as a direct replacement for MMBZ5245B?

A: MMBZ5245BLT1G is electrically compatible with MMBZ5245B for Zener voltage (15 V), tolerance (±5%), impedance (16 Ohms), and reverse leakage characteristics. The primary difference is reduced maximum power dissipation (225 mW versus 350 mW). Substitution is valid only if circuit power requirements do not exceed 225 mW.

Q: What is the difference between MMBZ5245B-7-F and MMBZ5245BQ-7-F?

A: Both parts are manufactured by Diodes Incorporated and provide identical electrical specifications (15 V, 350 mW, ±5%, 16 Ohms). MMBZ5245BQ-7-F includes automotive-grade qualification (AEC-Q101) and is rated for -65°C to 150°C operation. MMBZ5245B-7-F operates over -65°C to 150°C without automotive qualification.

Q: Are onsemi SZMMBZ5245 variants suitable for automotive applications?

A: Yes. SZMMBZ5245BLT1G and SZMMBZ5245ELT1G are qualified to AEC-Q101 automotive standards and are rated for -65°C to 150°C operation. These parts are suitable for automotive and industrial applications requiring enhanced reliability.

Q: How does BZX84C15-TP differ from MMBZ5245B?

A: BZX84C15-TP matches the MMBZ5245B in Zener voltage (15 V), power rating (350 mW), tolerance (±5%), and package (SOT-23-3). The impedance specification differs (30 Ohms versus 16 Ohms). This impedance variation is acceptable in most applications but should be verified against circuit design requirements.

Q: What packaging options are available for substitute parts?

A: Substitute parts are available in Cut Tape (CT) & Digi-Reel, Tape & Reel (TR), and Bulk packaging formats. Selection depends on production volume and assembly requirements. All parts maintain identical SOT-23-3 package specifications for mechanical compatibility.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed are RoHS3 compliant. The original MMBZ5245B does not specify RoHS status. All active production alternatives meet current RoHS3 requirements.

Q: Can BZX84B15-TP be used where tighter voltage tolerance is required?

A: Yes. BZX84B15-TP provides ±2% tolerance compared to ±5% for MMBZ5245B. This part is suitable for applications requiring improved voltage regulation accuracy while maintaining 15 V Zener voltage and 350 mW power rating.

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