MMBZ5246B Zener Diode 16V 350mW SOT-23-3 Equivalent & Substitute Parts

Part Overview

The MMBZ5246B is a 16V Zener diode rated for 350mW maximum power dissipation in a surface mount SOT-23-3 package manufactured by onsemi. This component is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. 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)	16	V
Power - Maximum	350	mW
Tolerance	±5%	—
Impedance (Maximum)	17	Ohms
Current - Reverse Leakage @ Vr	100 nA @ 12V	—
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 MMBZ5246B is determined by the following critical parameters:

Electrical Compatibility Requirements:

Zener voltage must equal 16V nominal
Package must be SOT-23-3 (TO-236-3, SC-59)
Mounting type must be surface mount
Operating temperature range must encompass or exceed the application requirement
Voltage tolerance must be acceptable for the circuit design

Power Rating Considerations: The MMBZ5246B is rated for 350mW maximum power dissipation. Substitute parts with lower power ratings (225mW or 250mW) are acceptable only when circuit design ensures power dissipation does not exceed the substitute part's maximum rating.

Impedance and Leakage Characteristics: Impedance (Zzt) and reverse leakage current are secondary parameters that influence circuit performance but do not prevent substitution when primary electrical parameters match.

Product Status and Compliance: Active substitute parts are preferred over obsolete components. RoHS3 compliance and automotive-grade qualifications (AEC-Q101) are available in substitute options and should be selected based on application requirements.

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Power (mW)	Tolerance	Zzt (Ohms)	Temp Range (°C)	Status	RoHS	Automotive
MMBZ5246B	onsemi	16	350	±5%	17	-55 to 150	Obsolete	—	—
BZX84B16LT1G	onsemi	16	250	±2%	40	-65 to 150	Active	ROHS3	—
BZX84C16LT1G	onsemi	16	225	±6%	40	-65 to 150	Active	ROHS3	—
MMBZ5246BLT1G	onsemi	16	225	±5%	17	-65 to 150	Active	ROHS3	—
SZBZX84B16LT1G	onsemi	16	250	±2%	40	-65 to 150	Active	ROHS3	AEC-Q101
SZBZX84C16ET1G	onsemi	16	225	±6%	40	-65 to 150	Active	ROHS3	AEC-Q101
SZBZX84C16ET3G	onsemi	16	225	±6%	40	-65 to 150	Active	ROHS3	AEC-Q101
SZBZX84C16LT1G	onsemi	16	250	±5%	40	-65 to 150	Active	ROHS3	AEC-Q101
SZBZX84C16LT3G	onsemi	16	250	±5%	40	-65 to 150	Active	ROHS3	AEC-Q101
SZMMBZ5246BLT1G	onsemi	16	225	±5%	17	-65 to 150	Active	ROHS3	AEC-Q101
SZMMBZ5246ELT1G	onsemi	16	225	±5%	17	-55 to 150	Active	ROHS3	AEC-Q101

Engineering Selection Recommendations

For Standard Commercial Applications: Select MMBZ5246BLT1G as the primary substitute. This part maintains the same base product number (MMBZ5246), identical impedance characteristic (17 Ohms), and matching voltage tolerance (±5%). The part is active, RoHS3 compliant, and operates across an extended temperature range (-65°C to 150°C). Power rating is reduced to 225mW; verify circuit design ensures power dissipation does not exceed this limit.

For Automotive Applications: Select SZMMBZ5246BLT1G or SZMMBZ5246ELT1G for AEC-Q101 qualified components. Both parts carry automotive-grade designation and maintain the MMBZ5246 base product characteristics. SZMMBZ5246ELT1G preserves the original operating temperature range (-55°C to 150°C). Power rating is 225mW; confirm circuit power budget compatibility.

For Applications Requiring Higher Power Dissipation: If circuit design requires power dissipation approaching 350mW, select SZBZX84B16LT1G or SZBZX84C16LT1G/LT3G. These parts offer 250mW power rating with AEC-Q101 automotive qualification. SZBZX84B16LT1G provides ±2% voltage tolerance; SZBZX84C16 variants provide ±5% or ±6% tolerance depending on specific part number.

For Non-Automotive Applications with Standard Requirements: BZX84B16LT1G or BZX84C16LT1G are suitable alternatives. Both are active, RoHS3 compliant, and available in high inventory quantities. BZX84B16LT1G offers ±2% tolerance with 250mW rating; BZX84C16LT1G offers ±6% tolerance with 225mW rating.

Frequently Asked Questions (FAQ)

Q: Can MMBZ5246B be directly replaced with a lower power-rated substitute?

A: Yes, provided circuit design ensures power dissipation does not exceed the substitute part's maximum rating. The MMBZ5246B is rated 350mW; substitutes rated 225mW or 250mW are electrically compatible if thermal conditions remain within limits. Verify power budget calculations before implementation.

Q: What is the difference between BZX84B16LT1G and BZX84C16LT1G?

A: Both parts are 16V Zener diodes in SOT-23-3 packages with identical power ratings (250mW and 225mW respectively). The primary difference is voltage tolerance: BZX84B16LT1G specifies ±2% tolerance, while BZX84C16LT1G specifies ±6% tolerance. Select based on circuit tolerance requirements.

Q: Are automotive-grade substitutes (SZBZX84 and SZMMBZ5246 series) compatible with non-automotive applications?

A: Yes. Automotive-grade parts meeting AEC-Q101 qualification are fully compatible with non-automotive applications. These parts exceed standard reliability requirements and are suitable for any application requiring the specified electrical parameters.

Q: What is the significance of the impedance (Zzt) parameter in substitution?

A: Impedance affects voltage regulation characteristics and transient response. The MMBZ5246B specifies 17 Ohms impedance. Substitutes with higher impedance (40 Ohms in BZX84 series) exhibit different dynamic behavior. For applications sensitive to impedance characteristics, select MMBZ5246BLT1G, SZMMBZ5246BLT1G, or SZMMBZ5246ELT1G, which maintain 17 Ohms impedance.

Q: Can MMBZ5246B be used in applications requiring -65°C minimum operating temperature?

A: No. The MMBZ5246B specifies -55°C minimum operating temperature. For applications requiring -65°C operation, select substitute parts with extended temperature range: BZX84B16LT1G, BZX84C16LT1G, MMBZ5246BLT1G, or any SZBZX84 or SZMMBZ5246 variant (all rated -65°C to 150°C).

Q: What packaging options are available for these substitutes?

A: All listed substitutes are supplied in SOT-23-3 (TO-236-3, SC-59) surface mount packages. Packaging format variations include Tape & Reel (TR) and Cut Tape (CT) & Digi-Reel options, which affect delivery and handling but do not alter electrical or mechanical compatibility.

Q: Is RoHS3 compliance required for MMBZ5246B replacement?

A: The original MMBZ5246B does not specify RoHS status. All active substitute parts listed are RoHS3 compliant. Select RoHS3 compliant substitutes for applications subject to RoHS regulations or when compliance is a design requirement.

Q: How do I determine which substitute is best for my application?

A: Identify three critical factors: (1) Required power dissipation—if below 225mW, any substitute is acceptable; if 225-250mW, select 250mW-rated parts; if above 250mW, reconsider design or use original part if available. (2) Operating temperature range—verify substitute minimum temperature meets application requirement. (3) Automotive qualification—select SZBZX84 or SZMMBZ5246 series if AEC-Q101 is required.

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