BZX55F20-TAP Equivalent & Substitute Parts

Part Overview

The BZX55F20-TAP is a 20 V, 500 mW Zener diode manufactured by Vishay General Semiconductor - Diodes Division in a through-hole DO-35 package. This component is classified as obsolete, which necessitates identification of equivalent and substitute parts for ongoing design requirements and production continuity. The part carries automotive-grade qualification (AEC-Q101) and maintains ROHS3 compliance. Substitute parts are selected based on matching electrical specifications and mechanical compatibility within the DO-35 package family.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	20	V
Power - Maximum	500	mW
Tolerance	±1%	—
Impedance (Maximum)	55	Ohms
Current - Reverse Leakage @ Vr	100	nA @ 15 V
Voltage - Forward (Maximum) @ If	1.5	V @ 200 mA
Operating Temperature	175	°C
Mounting Type	Through Hole	—
Package / Case	DO-204AH, DO-35, Axial	—
Grade	Automotive	—
Qualification	AEC-Q101	—

Substitute Part Grouping Explanation

Substitution of the BZX55F20-TAP is determined by the following critical parameters:

Primary Matching Criteria:

Zener voltage: 20 V nominal
Power dissipation: 500 mW maximum
Package type: DO-35 through-hole axial configuration
Mounting compatibility: Through-hole PCB assembly

Secondary Compatibility Factors:

Tolerance specification (±1%, ±2%, ±5%, ±10%)
Impedance range (20 to 62 Ohms)
Reverse leakage current specifications
Forward voltage characteristics
Operating temperature range

Substitute parts are grouped by tolerance class, as this parameter directly affects circuit performance in voltage regulation and protection applications. Parts with tighter tolerance specifications (±1%, ±2%) provide closer electrical equivalence to the original BZX55F20-TAP. Parts with wider tolerances (±5%, ±10%) remain functionally compatible but introduce greater voltage variation in the zener operating point.

Parameter Comparison

Parameter	BZX55F20-TAP	BZX55B20-TAP	1N5743C	1N3525A	1N6007A	1N6007B
Manufacturer	Vishay	Vishay	Microchip	Microchip	Microchip	Microchip
Voltage - Zener (Nom)	20 V	20 V	20 V	20 V	20 V	20 V
Tolerance	±1%	±2%	±1%	±5%	±10%	±5%
Power - Max	500 mW	500 mW	500 mW	500 mW	500 mW	500 mW
Impedance (Max)	55 Ohms	55 Ohms	55 Ohms	20 Ohms	62 Ohms	48 Ohms
Current - Reverse Leakage @ Vr	100 nA @ 15 V	100 nA @ 15 V	100 nA @ 14 V	—	100 nA @ 12 V	100 nA @ 15 V
Voltage - Forward (Max) @ If	1.5 V @ 200 mA	1.5 V @ 200 mA	900 mV @ 10 mA	1.1 V @ 200 mA	1.1 V @ 200 mA	1.1 V @ 200 mA
Operating Temperature	175°C	-65°C ~ 175°C	-65°C ~ 175°C	-65°C ~ 175°C	-65°C ~ 175°C	-65°C ~ 175°C
Product Status	Obsolete	Active	Active	Active	Active	Active
Grade	Automotive	Automotive	—	—	—	—
Qualification	AEC-Q101	AEC-Q101	—	—	—	—
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	RoHS non-compliant	RoHS non-compliant	RoHS non-compliant	RoHS non-compliant
Package / Case	DO-204AH, DO-35, Axial	DO-204AH, DO-35, Axial	DO-204AH, DO-35, Axial	DO-204AH, DO-35, Axial	DO-204AH, DO-35, Axial	DO-204AH, DO-35, Axial

Engineering Selection Recommendations

Primary Recommendation: BZX55B20-TAP

The BZX55B20-TAP is the closest functional equivalent to the BZX55F20-TAP. Both parts are manufactured by Vishay General Semiconductor - Diodes Division and share identical electrical specifications with the exception of tolerance (±2% versus ±1%). The BZX55B20-TAP carries active product status, automotive-grade qualification (AEC-Q101), and ROHS3 compliance. The operating temperature range extends to -65°C, providing broader environmental coverage than the original part. This substitute is suitable for direct replacement in automotive and industrial applications requiring AEC-Q101 certification.

Secondary Recommendation: 1N5743C

The 1N5743C, manufactured by Microchip Technology, matches the BZX55F20-TAP in zener voltage (20 V), power rating (500 mW), and tolerance specification (±1%). This part maintains active product status and operates across the -65°C to 175°C temperature range. However, the 1N5743C is RoHS non-compliant and does not carry automotive-grade qualification or AEC-Q101 certification. This substitute is appropriate for non-automotive applications where RoHS compliance is not required.

Tertiary Recommendations: 1N6007B and 1N3525A

The 1N6007B and 1N3525A are Microchip Technology parts with active product status. Both maintain the 20 V zener voltage and 500 mW power rating. The 1N6007B offers ±5% tolerance with impedance of 48 Ohms, while the 1N3525A provides ±5% tolerance with lower impedance of 20 Ohms. These parts extend the operating temperature range to -65°C but do not carry automotive qualification or RoHS compliance. Selection between these parts depends on impedance requirements in the application circuit.

Alternative: 1N6007A

The 1N6007A provides the widest tolerance specification (±10%) among available substitutes. This part is suitable only for applications where voltage regulation tolerance is not critical. The 1N6007A carries active product status and operates across -65°C to 175°C but lacks automotive qualification and RoHS compliance.

Frequently Asked Questions (FAQ)

Q: Can BZX55B20-TAP directly replace BZX55F20-TAP in automotive applications?

A: Yes. The BZX55B20-TAP is a direct substitute for automotive use. Both parts carry AEC-Q101 qualification, automotive-grade designation, and ROHS3 compliance. The tolerance difference (±2% versus ±1%) is acceptable in most automotive voltage regulation and protection circuits. The BZX55B20-TAP provides extended operating temperature range (-65°C to 175°C) and active product availability.

Q: What is the significance of tolerance specifications in zener diode substitution?

A: Tolerance directly affects the precision of voltage regulation. The BZX55F20-TAP specifies ±1% tolerance, meaning the zener voltage operates between 19.8 V and 20.2 V. The BZX55B20-TAP with ±2% tolerance operates between 19.6 V and 20.4 V. Wider tolerances (±5%, ±10%) introduce greater voltage variation. Selection depends on circuit requirements for voltage accuracy. Tighter tolerance parts (±1%, ±2%) are preferred for precision voltage reference applications.

Q: Are Microchip Technology substitutes suitable for automotive applications?

A: Microchip Technology substitutes (1N5743C, 1N3525A, 1N6007A, 1N6007B) do not carry automotive-grade qualification or AEC-Q101 certification. These parts are suitable for industrial and consumer applications but are not recommended for automotive use where AEC-Q101 compliance is required. For automotive applications, the BZX55B20-TAP is the appropriate substitute.

Q: What is the impact of impedance variation among substitute parts?

A: Impedance affects the dynamic response of the zener diode in voltage regulation circuits. The BZX55F20-TAP specifies 55 Ohms maximum impedance. Substitute parts range from 20 Ohms (1N3525A) to 62 Ohms (1N6007A). Lower impedance provides faster transient response and better load regulation. Higher impedance may introduce greater voltage ripple under dynamic load conditions. Circuit simulation or testing is necessary to confirm impedance compatibility in specific applications.

Q: Why is RoHS compliance important in substitute selection?

A: ROHS3 compliance indicates the part meets European Union restrictions on hazardous substances. The BZX55F20-TAP and BZX55B20-TAP are ROHS3 compliant. Microchip Technology substitutes are RoHS non-compliant. For applications subject to RoHS regulations or customer requirements, only ROHS3-compliant substitutes (BZX55B20-TAP) are acceptable.

Q: Can the DO-35 package be used interchangeably with other package designations?

A: The DO-35 package is the standard through-hole axial package for these zener diodes. All listed substitutes use the DO-35 package (also designated DO-204AH). These packages are mechanically and electrically interchangeable for through-hole PCB assembly. No package conversion is required.

Q: What is the difference between forward voltage specifications at different current levels?

A: Forward voltage varies with forward current. The BZX55F20-TAP specifies 1.5 V maximum at 200 mA forward current. The 1N5743C specifies 900 mV at 10 mA, which is a lower current condition. These specifications reflect different measurement conditions and do not indicate incompatibility. Forward voltage characteristics are relevant only when the diode conducts in the forward direction, which is not the primary operating mode for zener voltage regulation.

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