BZX79C3V0 Equivalent & Substitute Parts

Part Overview

The BZX79C3V0 is a Zener diode rated at 3 V nominal voltage with 500 mW power dissipation and ±5% tolerance, housed in a DO-35 through-hole package. Manufactured by onsemi, this component is classified as obsolete. Due to its obsolete status, equivalent and substitute parts from active manufacturers are necessary for new designs, production continuity, and long-term component availability. Substitute parts must maintain electrical compatibility across voltage regulation, power handling, and thermal operating ranges while accommodating the through-hole DO-35 package form factor.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	3	V
Tolerance	±5%	—
Power - Max	500	mW
Impedance (Max)	95	Ohms
Current - Reverse Leakage @ Vr	50	µA @ 1 V
Voltage - Forward (Vf) (Max) @ If	1.5	V @ 100 mA
Operating Temperature	-65 to 200	°C
Mounting Type	Through Hole	—
Package / Case	DO-204AH, DO-35, Axial	—

Substitute Part Grouping Explanation

Substitution of the BZX79C3V0 is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - Zener (Nom): 3 V (exact match required)
Tolerance: ±5% or tighter (±5%, ±2%, ±1% acceptable; ±10% acceptable with design review)
Power - Max: 500 mW or greater
Mounting Type: Through Hole
Package / Case: DO-35 or DO-204AH compatible

Secondary Compatibility Parameters:

Impedance (Max): Values between 29 Ohms and 1600 Ohms are acceptable within the 3 V zener classification
Current - Reverse Leakage @ Vr: Acceptable range 10 nA to 400 nA @ 1 V or 50 µA @ 1 V
Voltage - Forward (Vf) (Max) @ If: Acceptable range 900 mV @ 10 mA to 1.5 V @ 100 mA
Operating Temperature: Minimum -65°C to maximum 175°C or higher

Substitute parts are grouped into two categories based on power rating alignment:

Category A (500 mW rated): 1N5225B, 1N4372A, 1N5987A, 1N5987B, 1N5987C, 1N5987D

Category B (400 mW rated): BZX79-C3V0,113, BZX79-C3V0,133, BZX79-C3V0,143, 1N4619-1

Category A parts provide direct 500 mW power rating equivalence. Category B parts operate at 400 mW, representing a 20% reduction in power dissipation capacity and require design verification for applications operating near maximum power limits.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power (Max)	Zzt (Max)	Vf (Max) @ If	Temp Range	Status
BZX79C3V0	onsemi	3 V	±5%	500 mW	95 Ω	1.5 V @ 100 mA	-65 to 200°C	Obsolete
1N5225B	Taiwan Semiconductor Corporation	3 V	±5%	500 mW	29 Ω	1.1 V @ 200 mA	-65 to 200°C	Active
1N4372A	Microchip Technology	3 V	±5%	500 mW	29 Ω	1.1 V @ 200 mA	-65 to 175°C	Active
1N4619-1	Microchip Technology	3 V	±5%	500 mW	1600 Ω	1.1 V @ 200 mA	-65 to 175°C	Active
1N5987A	Microchip Technology	3 V	±10%	500 mW	100 Ω	1.1 V @ 200 mA	-65 to 175°C	Active
1N5987B	Microchip Technology	3 V	±5%	500 mW	95 Ω	1.1 V @ 200 mA	-65 to 175°C	Active
1N5987C	Microchip Technology	3 V	±2%	500 mW	95 Ω	1.1 V @ 200 mA	-65 to 175°C	Active
1N5987D	Microchip Technology	3 V	±1%	500 mW	95 Ω	1.1 V @ 200 mA	-65 to 175°C	Active
BZX79-C3V0,113	NXP Semiconductors	3 V	±5%	400 mW	95 Ω	900 mV @ 10 mA	-65 to 200°C	Active
BZX79-C3V0,133	NXP Semiconductors	3 V	±5%	400 mW	95 Ω	900 mV @ 10 mA	-65 to 200°C	Active
BZX79-C3V0,143	Nexperia USA Inc.	3 V	±5%	400 mW	95 Ω	900 mV @ 10 mA	-65 to 200°C	Active

Engineering Selection Recommendations

Primary Recommendation - Direct Equivalents (500 mW Category):

The 1N5987B and 1N5987C from Microchip Technology provide the closest electrical equivalence to the BZX79C3V0. Both maintain 3 V nominal zener voltage, 500 mW power rating, and ±5% or tighter tolerance. The 1N5987B offers ±5% tolerance matching the original specification, while 1N5987C provides superior ±2% tolerance for applications requiring tighter voltage regulation. Both are active products with unlimited moisture sensitivity level (MSL 1) and REACH compliance.

Secondary Recommendation - Alternative 500 mW Options:

The 1N5225B from Taiwan Semiconductor Corporation and 1N4372A from Microchip Technology both meet the 500 mW power requirement with ±5% tolerance. The 1N5225B extends the upper operating temperature to 200°C, matching the original BZX79C3V0 specification. Both parts are active and widely available.

Tolerance-Specific Selection:

For applications requiring tighter voltage tolerance, 1N5987C (±2%) and 1N5987D (±1%) provide enhanced precision. For applications tolerating wider tolerance, 1N5987A (±10%) is available, though this represents a deviation from the original ±5% specification.

Lower Power Alternative (400 mW Category):

The BZX79-C3V0 series from NXP Semiconductors (variants 113, 133, 143) operates at 400 mW maximum power dissipation. These parts are suitable only for applications where the circuit design does not require the full 500 mW capacity. The NXP variants maintain the extended -65°C to 200°C operating temperature range and offer high inventory availability.

Compliance and Product Status:

All recommended substitute parts are active products with REACH compliance and unlimited moisture sensitivity level. The 1N5225B carries RoHS3 compliance. Selection should prioritize active products to ensure long-term availability and supply chain continuity.

Frequently Asked Questions (FAQ)

Q: Can the 1N5987A (±10% tolerance) be used as a direct substitute for the BZX79C3V0 (±5% tolerance)?

A: The 1N5987A meets all electrical and mechanical parameters for the 3 V, 500 mW zener diode classification. However, the ±10% tolerance represents a wider voltage variation band than the original ±5% specification. This substitution is acceptable only if the circuit design accommodates the wider tolerance range. Applications with strict voltage regulation requirements should select parts with ±5% or tighter tolerance.

Q: What is the difference between the BZX79-C3V0,113, BZX79-C3V0,133, and BZX79-C3V0,143 variants?

A: These three part numbers represent the same electrical component (3 V, 400 mW zener diode) with different packaging and distribution configurations. The ,113 and ,133 variants are supplied in bulk packaging, while the ,143 variant is supplied in cut tape (CT) format. All three are electrically identical and interchangeable. The primary distinction is the 400 mW power rating versus the 500 mW rating of other substitutes.

Q: Is the 1N4619-1 suitable for high-current applications?

A: The 1N4619-1 exhibits significantly higher impedance (1600 Ohms maximum) and lower reverse leakage current (400 nanoamperes at 1 V) compared to the BZX79C3V0 (95 Ohms impedance, 50 microamperes at 1 V). This characteristic makes the 1N4619-1 suitable for low-current, precision voltage reference applications rather than high-current regulation circuits. Selection depends on the specific circuit requirements for impedance and leakage characteristics.

Q: Can I use a 400 mW rated zener diode (BZX79-C3V0 series) in place of the 500 mW BZX79C3V0?

A: The BZX79-C3V0 series (400 mW) can be used only if the circuit design operates below 400 mW power dissipation. If the original design requires the full 500 mW capacity, the 400 mW variants will not provide adequate thermal margin and may experience premature failure. Circuit analysis must confirm that maximum power dissipation remains below 400 mW under all operating conditions.

Q: What is the significance of the different forward voltage specifications (1.5 V @ 100 mA vs. 1.1 V @ 200 mA)?

A: Forward voltage specifications are provided at different test currents. The BZX79C3V0 specifies 1.5 V at 100 mA, while most substitutes specify 1.1 V at 200 mA. These represent measurements at different operating points on the diode's forward characteristic curve. Both specifications are valid for the respective test conditions. Circuit designs should reference the forward voltage specification at the actual operating current of the application.

Q: Are all substitute parts available in the same DO-35 package?

A: All substitute parts listed are housed in DO-35 or DO-204AH packages, which are mechanically and electrically compatible. The BZX79-C3V0 series uses the ALF2 supplier device package designation, which corresponds to the DO-35 form factor. All parts are suitable for through-hole PCB mounting with identical lead spacing and dimensions.

Q: Which substitute offers the best long-term availability?

A: The 1N5987B and 1N5987C from Microchip Technology, along with the BZX79-C3V0 series from NXP Semiconductors, demonstrate high inventory levels (885 to 410,863 pieces) and active product status. These parts are established industry standards with multiple suppliers and represent the most reliable choices for long-term design continuity.

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