MMBZ5230B Equivalent & Substitute Parts

Part Overview

The MMBZ5230B is a 4.7 V Zener diode rated at 350 mW in a surface mount SOT-23-3 package, manufactured by onsemi. This part is classified as obsolete, though it remains in stock with 15,788 units available. The obsolete status necessitates identification of active equivalent and substitute components that maintain electrical and mechanical compatibility for new designs and ongoing production requirements.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	4.7	V
Tolerance	±5%	—
Power - Maximum	350	mW
Impedance (Maximum)	19	Ohms
Current - Reverse Leakage @ 2V	5	µA
Voltage - Forward (Maximum) @ 10 mA	900	mV
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	TO-236-3, SC-59, SOT-23-3	—

Substitute Part Grouping Explanation

Substitution of the MMBZ5230B is determined by the following critical parameters:

Electrical Compatibility Requirements:

Zener voltage: 4.7 V nominal
Power dissipation capability: minimum 350 mW (or lower if application permits)
Impedance characteristics: maximum 19 Ohms (or higher impedance acceptable if application tolerates)
Reverse leakage current: 5 µA @ 2 V (or lower acceptable)
Forward voltage: 900 mV maximum @ 10 mA
Voltage tolerance: ±5% (or tighter tolerance acceptable)

Mechanical Compatibility Requirements:

Package type: SOT-23-3 / TO-236-3 / SC-59 (pin-compatible)
Mounting type: Surface Mount

Operational Requirements:

Operating temperature range: -55°C to 150°C minimum (extended range acceptable)

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

Similar Substitutes – Active parts with identical or superior electrical specifications and full package compatibility
Direct Substitutes – Alternative manufacturer equivalents with matching electrical and mechanical specifications
Upgrade Substitutes – Active parts with enhanced specifications or certifications

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (mW)	Zzt (Ω)	Temp Range (°C)	Status	RoHS
MMBZ5230B	onsemi	4.7	±5%	350	19	-55 to 150	Obsolete	—
BZX84C4V7LT1G	onsemi	4.7	±6%	225	80	-65 to 150	Active	ROHS3
MMBZ5230BLT1G	onsemi	4.7	±5%	225	19	-65 to 150	Active	ROHS3
SZBZX84B4V7LT1G	onsemi	4.7	±2%	250	80	-65 to 150	Active	ROHS3
SZBZX84C4V7LT1G	onsemi	4.7	±6%	225	80	-65 to 150	Active	ROHS3
SZBZX84C4V7LT3G	onsemi	4.7	±6%	225	80	-65 to 150	Active	ROHS3
CMPZ5230B BK PBFREE	Central Semiconductor Corp	4.7	±5%	350	19	-65 to 150	Active	ROHS3
CMPZ5230B TR PBFREE	Central Semiconductor Corp	4.7	±5%	350	19	-65 to 150	Active	ROHS3
CZRT5230B-HF	Comchip Technology	4.7	±5%	350	19	-65 to 150	Active	ROHS3
MMBZ5230B-7-F	Diodes Incorporated	4.7	±5%	350	19	-65 to 150	Active	ROHS3
BZX84-A4V7,215	Nexperia USA Inc.	4.7	±1%	250	80	-65 to 150	Active	ROHS3

Engineering Selection Recommendations

For Direct Replacement (Identical Specifications):

The following parts provide exact electrical and mechanical equivalence to the MMBZ5230B with active product status and RoHS3 compliance:

CMPZ5230B BK PBFREE (Central Semiconductor Corp, Bulk packaging) – Identical 350 mW power rating, ±5% tolerance, 19 Ohm impedance
CMPZ5230B TR PBFREE (Central Semiconductor Corp, Tape & Reel packaging) – Identical specifications with tape and reel packaging option
CZRT5230B-HF (Comchip Technology) – Identical electrical specifications with active status
MMBZ5230B-7-F (Diodes Incorporated) – Identical specifications from alternative manufacturer

For Power-Reduced Applications:

When application design permits lower power dissipation, the following active parts are suitable:

MMBZ5230BLT1G (onsemi) – Maintains ±5% tolerance and 19 Ohm impedance with 225 mW rating; extended temperature range to -65°C
BZX84C4V7LT1G (onsemi) – 225 mW rating with extended temperature range; ±6% tolerance acceptable for general applications
SZBZX84C4V7LT1G and SZBZX84C4V7LT3G (onsemi) – 225 mW automotive-grade parts with AEC-Q101 qualification

For Precision Applications:

BZX84-A4V7,215 (Nexperia USA Inc.) – Tighter ±1% tolerance with automotive qualification and AEC-Q101 certification; 250 mW rating

For Automotive Applications:

SZBZX84B4V7LT1G (onsemi) – Automotive-grade with AEC-Q101 qualification, ±2% tolerance, 250 mW rating
SZBZX84C4V7LT1G and SZBZX84C4V7LT3G (onsemi) – Automotive-grade alternatives with AEC-Q101 qualification
BZX84-A4V7,215 (Nexperia USA Inc.) – Automotive-qualified with AEC-Q101 certification

All recommended substitutes maintain SOT-23-3 package compatibility and surface mount mounting type. All active substitutes carry RoHS3 compliance status.

Frequently Asked Questions (FAQ)

Q: Can I use a lower power-rated substitute if my application does not require 350 mW?

A: Yes. The MMBZ5230BLT1G (225 mW) and BZX84C4V7LT1G (225 mW) are suitable for applications with lower power requirements. Verify that your circuit design does not exceed the lower power rating during normal operation and worst-case conditions.

Q: What is the difference between the onsemi MMBZ5230BLT1G and the SZBZX84C4V7LT1G?

A: Both maintain 4.7 V nominal voltage and 225 mW power rating. The MMBZ5230BLT1G has ±5% tolerance and 19 Ohm impedance. The SZBZX84C4V7LT1G has ±6% tolerance, 80 Ohm impedance, and automotive AEC-Q101 qualification. Select based on tolerance requirements and automotive qualification needs.

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

A: No. The MMBZ5230B was supplied in standard packaging. Substitutes are available in Cut Tape (CT) & Digi-Reel, Tape & Reel (TR), and Bulk packaging options. Verify packaging availability with your supplier for your production requirements.

Q: Can I use the BZX84-A4V7,215 with ±1% tolerance in place of the ±5% MMBZ5230B?

A: Yes. The tighter ±1% tolerance of the BZX84-A4V7,215 is a superior specification and is fully compatible. This part is suitable for applications requiring higher precision voltage regulation.

Q: What is the temperature range difference between the obsolete MMBZ5230B and active substitutes?

A: The MMBZ5230B operates from -55°C to 150°C. Most active substitutes extend the lower temperature limit to -65°C, providing a wider operating range. This extended range is beneficial for applications in harsh environments and does not restrict use in standard temperature applications.

Q: Are automotive-qualified parts necessary for my application?

A: Automotive-qualified parts (SZBZX84B4V7LT1G, SZBZX84C4V7LT1G, SZBZX84C4V7LT3G, BZX84-A4V7,215) carry AEC-Q101 certification and are required only for automotive applications. For general industrial and consumer applications, standard-grade parts are appropriate.

Q: What does the impedance (Zzt) parameter indicate, and why does it vary among substitutes?

A: Impedance (Zzt) represents the dynamic impedance of the Zener diode at the test current. The MMBZ5230B has 19 Ohm impedance, while some substitutes have 80 Ohm impedance. Lower impedance provides better voltage regulation stability. Verify impedance requirements for your specific voltage regulation application.

Q: Can I substitute the MMBZ5230B in existing PCB designs without layout changes?

A: Yes. All recommended substitutes use the SOT-23-3 package with identical pin configuration and footprint. No PCB layout modifications are required for mechanical compatibility.

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