BZX84C3V9-7 Equivalent & Substitute Parts

Part Overview

The BZX84C3V9-7 is a 3.9 V zener diode rated for 300 mW maximum power dissipation in a surface mount SOT-23-3 package, manufactured by Diodes Incorporated. This part is discontinued at DiGi Electronics, necessitating identification of functionally equivalent alternatives. Substitute parts must maintain the same nominal zener voltage, operating temperature range, package form factor, and electrical characteristics within specified tolerances to ensure direct circuit compatibility.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	3.9	V
Tolerance	±5%	%
Power - Max	300	mW
Impedance (Max)	90	Ohms
Current - Reverse Leakage @ Vr	3	µA @ 1 V
Voltage - Forward (Vf) (Max) @ If	900	mV @ 10 mA
Operating Temperature	-65 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	TO-236-3, SC-59, SOT-23-3	—

Substitute Part Grouping Explanation

Substitution of the BZX84C3V9-7 is determined by the following critical parameters:

Primary Substitution Criteria:

Nominal zener voltage: 3.9 V (exact match required)
Package form factor: SOT-23-3 / TO-236-3 / SC-59 (physical and electrical compatibility)
Operating temperature range: -65°C to 150°C minimum
Mounting type: Surface Mount

Secondary Compatibility Parameters:

Tolerance: ±5% or tighter acceptable
Power rating: 300 mW or greater acceptable
Impedance (Max): 90 Ohms or lower acceptable
Reverse leakage current: 3 µA @ 1 V or lower acceptable
Forward voltage: 900 mV @ 10 mA or lower acceptable

Substitute parts are grouped into three categories based on electrical performance and product status:

Category 1 - Direct Manufacturer Equivalent (Diodes Incorporated): BZX84C3V9-7-F provides identical electrical specifications with improved RoHS3 compliance and active product status.

Category 2 - Parametric Equivalents (Tighter Tolerance/Higher Power): BZX84B3V9-7-F (±2% tolerance), BZX84C3V9 TR PBFREE (350 mW), and BZX84C3V9-TP (350 mW) offer equal or superior electrical performance.

Category 3 - Functional Equivalents (Reduced Power Rating): BZX84-A3V9,215, BZX84-C3V9,215, BZX84-C3V9,235, BZX84C3V9LT1G, MMBZ5228BLT1G, and SZBZX84C3V9LT1G operate within acceptable parameters with power ratings of 225–250 mW, suitable for applications not requiring the full 300 mW dissipation.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power (Max)	Zzt (Max)	Leakage @ Vr	Vf (Max) @ If	Temp Range	Package	Status
BZX84C3V9-7	Diodes Inc.	3.9 V	±5%	300 mW	90 Ω	3 µA @ 1 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Discontinued
BZX84C3V9-7-F	Diodes Inc.	3.9 V	±5%	300 mW	90 Ω	3 µA @ 1 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Active
BZX84B3V9-7-F	Diodes Inc.	3.9 V	±2%	300 mW	90 Ω	3 µA @ 1 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Active
BZX84C3V9 TR PBFREE	Central Semiconductor	3.9 V	±5%	350 mW	90 Ω	3 µA @ 1 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Active
BZX84-A3V9,215	Nexperia USA	3.9 V	±1%	250 mW	90 Ω	3 µA @ 1 V	900 mV @ 10 mA	-65 to 150°C	TO-236AB	Active
BZX84-C3V9,215	Nexperia USA	3.9 V	±5%	250 mW	90 Ω	3 µA @ 1 V	900 mV @ 10 mA	-65 to 150°C	TO-236AB	Active
BZX84-C3V9,235	NXP USA	3.9 V	±5%	250 mW	90 Ω	3 µA @ 1 V	900 mV @ 10 mA	-65 to 150°C	SOT-23	Active
BZX84C3V9-TP	Micro Commercial Co	3.9 V	±5%	350 mW	90 Ω	3 µA @ 1 V	900 mV @ 10 mA	-55 to 150°C	SOT-23-3	Active
BZX84C3V9LT1G	onsemi	3.9 V	±5%	225 mW	90 Ω	3 µA @ 1 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Active
MMBZ5228BLT1G	onsemi	3.9 V	±5%	225 mW	23 Ω	10 µA @ 1 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Active
SZBZX84C3V9LT1G	onsemi	3.9 V	±5%	225 mW	90 Ω	3 µA @ 1 V	900 mV @ 10 mA	-65 to 150°C	SOT-23-3	Active

Engineering Selection Recommendations

First Priority - Direct Equivalent: BZX84C3V9-7-F (Diodes Incorporated) is the primary substitute. It maintains identical electrical specifications and package form factor while offering active product status and RoHS3 compliance. This part provides the highest confidence for direct replacement with no circuit redesign required.

Second Priority - Enhanced Performance: BZX84B3V9-7-F (Diodes Incorporated) offers tighter tolerance (±2% versus ±5%), maintaining all other electrical parameters. This part is suitable for applications requiring improved voltage accuracy.

BZX84C3V9 TR PBFREE (Central Semiconductor Corp) and BZX84C3V9-TP (Micro Commercial Co) provide increased power dissipation capability (350 mW versus 300 mW) while maintaining identical voltage and impedance specifications. These parts are suitable for applications with higher thermal demands.

Third Priority - Functional Equivalents with Reduced Power Rating: BZX84-A3V9,215 and BZX84-C3V9,215 (Nexperia USA Inc.) and BZX84-C3V9,235 (NXP USA Inc.) operate at 250 mW maximum power. These parts carry AEC-Q101 automotive qualification and are suitable for applications not requiring the full 300 mW dissipation capability.

BZX84C3V9LT1G and SZBZX84C3V9LT1G (onsemi) operate at 225 mW maximum power. SZBZX84C3V9LT1G carries AEC-Q101 automotive qualification. These parts are suitable for low-power applications.

MMBZ5228BLT1G (onsemi) operates at 225 mW with lower impedance (23 Ω versus 90 Ω) and higher reverse leakage (10 µA versus 3 µA). This part is suitable for applications where lower impedance is beneficial and leakage current tolerance is acceptable.

Compliance Considerations: All substitute parts listed are RoHS3 compliant and REACH unaffected. The original BZX84C3V9-7 is RoHS non-compliant; substitution with any listed alternative improves regulatory compliance.

Frequently Asked Questions (FAQ)

Q: Can BZX84C3V9-7-F be used as a direct replacement for BZX84C3V9-7?

A: Yes. BZX84C3V9-7-F is electrically and mechanically identical to BZX84C3V9-7, with the same 3.9 V nominal voltage, 300 mW power rating, ±5% tolerance, and SOT-23-3 package. The primary difference is active product status and improved RoHS3 compliance.

Q: What is the difference between BZX84B3V9-7-F and BZX84C3V9-7-F?

A: The tolerance specification differs. BZX84B3V9-7-F offers ±2% tolerance compared to ±5% for BZX84C3V9-7-F. All other electrical parameters and the package form factor remain identical. Select BZX84B3V9-7-F for applications requiring tighter voltage accuracy.

Q: Can I use a 225 mW zener diode in place of a 300 mW part?

A: Substitution is acceptable only if the circuit design does not require the full 300 mW dissipation capability. Parts such as BZX84C3V9LT1G, MMBZ5228BLT1G, and SZBZX84C3V9LT1G are rated for 225 mW. Verify that the maximum power dissipation in the application does not exceed 225 mW before substitution.

Q: What is the significance of the SOT-23-3 package designation?

A: SOT-23-3, TO-236-3, and SC-59 are equivalent package designations for the same three-terminal surface mount form factor. All substitute parts listed use this package family, ensuring mechanical and electrical compatibility with the original BZX84C3V9-7 footprint.

Q: Are automotive-qualified parts available as substitutes?

A: Yes. BZX84-A3V9,215, BZX84-C3V9,215, and SZBZX84C3V9LT1G carry AEC-Q101 automotive qualification. These parts are suitable for automotive applications requiring qualified components.

Q: What is the operating temperature range for substitute parts?

A: Most substitute parts operate from -65°C to 150°C, matching the original BZX84C3V9-7. BZX84C3V9-TP (Micro Commercial Co) operates from -55°C to 150°C, providing a narrower low-temperature range. Verify application requirements before selecting this part.

Q: How does impedance affect zener diode selection?

A: Impedance (Zzt) affects voltage regulation quality under varying load conditions. The original BZX84C3V9-7 specifies 90 Ohms maximum impedance. Most substitutes maintain this specification. MMBZ5228BLT1G offers lower impedance (23 Ω), providing superior voltage regulation. Higher impedance values are not acceptable substitutes.

Q: What is the difference between cut tape and tape & reel packaging?

A: Cut tape (CT) and tape & reel (TR) are supply formats for the same component. Cut tape is supplied in smaller quantities on individual strips, while tape & reel is supplied in continuous reels for automated assembly. Electrical specifications remain identical; selection depends on procurement volume and assembly equipment compatibility.

Q: Can MMBZ5228BLT1G be used as a substitute despite different impedance and leakage specifications?

A: MMBZ5228BLT1G maintains the 3.9 V nominal voltage, ±5% tolerance, and SOT-23-3 package. However, it specifies 23 Ω impedance (versus 90 Ω) and 10 µA reverse leakage (versus 3 µA). This part is suitable for applications where lower impedance is beneficial. Verify that the higher leakage current does not affect circuit performance before substitution.

Q: Is RoHS compliance important for this substitution?

A: The original BZX84C3V9-7 is RoHS non-compliant. All listed substitute parts are RoHS3 compliant. If the application or supply chain requires RoHS compliance, any substitute part listed provides improved regulatory status.

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