1N4757G R0G Zener Diode Equivalent & Substitute Parts

Part Overview

The 1N4757G R0G is a 51 V, 1 W Zener diode manufactured by Taiwan Semiconductor Corporation in DO-204AL (DO-41) axial through-hole packaging. This component is classified as Active product status with full RoHS3 compliance and REACH unaffected designation. Zener diodes of this specification are used in voltage regulation, overvoltage protection, and reference voltage circuits. Equivalent and substitute parts are identified based on matching electrical characteristics and mechanical compatibility within the DO-41 package family.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	51	V
Tolerance	±5%	%
Power - Maximum	1	W
Impedance (Maximum)	95	Ohms
Current - Reverse Leakage @ Vr	5	µA @ 38.8 V
Voltage - Forward (Maximum) @ If	1.2	V @ 200 mA
Operating Temperature Range	-65 to 200	°C
Mounting Type	Through Hole	—
Package / Case	DO-204AL, DO-41, Axial	—

Substitute Part Grouping Explanation

Substitution of the 1N4757G R0G is determined by the following critical parameters:

Primary Matching Criteria:

Zener voltage: 51 V nominal
Tolerance: ±5%
Power rating: 1 W or greater
Package type: DO-204AL (DO-41) through-hole axial
Mounting type: Through hole

Secondary Compatibility Factors:

Impedance (Zzt): Maximum 95 Ohms or lower
Reverse leakage current: 5 µA or lower at specified reverse voltage
Forward voltage: 1.2 V or lower at 200 mA
Operating temperature range: Minimum -65°C to 200°C coverage
RoHS3 compliance and REACH unaffected status

Substitute parts are grouped into two categories: Direct Equivalents (51 V rating, 1 W power class) and Enhanced Alternatives (51 V rating, higher power ratings or improved specifications).

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance	Power (W)	Zzt (Ohms)	Reverse Leakage @ Vr	Vf (Max) @ If	Temp Range (°C)	Package	Status
1N4757G R0G	Taiwan Semiconductor	51	±5%	1	95	5 µA @ 38.8 V	1.2 V @ 200 mA	-65 to 200	DO-204AL (DO-41)	Active
1N4757A	Fairchild Semiconductor	51	±5%	1	95	5 µA @ 38.8 V	1.2 V @ 200 mA	-65 to 175	DO-41	Active
1N4757A-TAP	Vishay General Semiconductor	51	±5%	1.31	95	5 µA @ 38.8 V	1.2 V @ 200 mA	-65 to 175	DO-204AL (DO-41)	Active
1N4758A	SMC Diode Solutions	56	±5%	1	110	5 µA @ 42.6 V	1.2 V @ 200 mA	-65 to 200	DO-41	Obsolete
1N4758A-T50A	onsemi	56	±5%	1	110	5 µA @ 42.6 V	—	-65 to 200	DO-41	Active
1N5942BRLG	onsemi	51	±5%	3	70	1 µA @ 38.8 V	1.5 V @ 200 mA	-65 to 200	Axial	Active
BZX85C51-TAP	Vishay General Semiconductor	51	±5%	1.3	115	500 nA @ 39 V	—	-55 to 175	DO-204AL (DO-41)	Active
BZX85C51-TR	Vishay General Semiconductor	51	±5%	1.3	115	500 nA @ 39 V	—	-55 to 175	DO-204AL (DO-41)	Active
ZPY51-TR	Vishay General Semiconductor	51	±5%	1.3	45	500 nA @ 38 V	—	-55 to 175	DO-204AL (DO-41)	Active

Engineering Selection Recommendations

Direct Equivalents (51 V, 1 W Class):

The 1N4757A (Fairchild Semiconductor) and 1N4757A-TAP (Vishay General Semiconductor) are direct electrical equivalents to the 1N4757G R0G. Both maintain 51 V nominal zener voltage, ±5% tolerance, 1 W power rating, and 95 Ohms maximum impedance. The 1N4757A-TAP offers enhanced power dissipation at 1.31 W and is qualified to AEC-Q101 automotive standard. Operating temperature range for both is -65°C to 175°C, which covers the primary operating window of the main part. Both are Active product status with RoHS3 compliance.

Enhanced Alternatives (51 V, Higher Power):

The 1N5942BRLG (onsemi) provides 51 V zener voltage with 3 W power rating, offering superior thermal performance for applications requiring higher power dissipation. This part features lower impedance (70 Ohms) and reduced reverse leakage (1 µA). Operating temperature range is -65°C to 200°C, matching the main part specification. Package is axial through-hole, compatible with DO-41 footprints. Active product status with RoHS3 compliance.

The BZX85C51-TAP and BZX85C51-TR (Vishay General Semiconductor) both provide 51 V zener voltage with 1.3 W power rating and AEC-Q101 automotive qualification. These parts feature 115 Ohms impedance and significantly lower reverse leakage (500 nA). Operating temperature range is -55°C to 175°C. Both are Active product status with RoHS3 compliance.

The ZPY51-TR (Vishay General Semiconductor) provides 51 V zener voltage with 1.3 W power rating and AEC-Q101 automotive qualification. This part features the lowest impedance (45 Ohms) among all substitutes and 500 nA reverse leakage. Operating temperature range is -55°C to 175°C. Active product status with RoHS3 compliance.

Non-Equivalent Alternative:

The 1N4758A and 1N4758A-T50A feature 56 V zener voltage, which differs from the 51 V specification of the main part. These parts are not direct substitutes for applications requiring precise 51 V regulation. The 1N4758A is Obsolete product status; the 1N4758A-T50A is Active.

Frequently Asked Questions (FAQ)

Q: Can the 1N4757A replace the 1N4757G R0G in all applications?

A: The 1N4757A is electrically equivalent with matching 51 V zener voltage, ±5% tolerance, 1 W power rating, and 95 Ohms impedance. Operating temperature range is -65°C to 175°C, which covers standard operating conditions. Mechanical compatibility is confirmed through DO-41 package type. Substitution is valid for applications within this temperature range.

Q: What is the advantage of using 1N5942BRLG over the main part?

A: The 1N5942BRLG maintains the 51 V zener voltage specification while providing 3 W power rating compared to 1 W in the main part. This higher power rating enables greater heat dissipation capability. Impedance is lower at 70 Ohms, and reverse leakage is reduced to 1 µA. Operating temperature range extends to -65°C to 200°C. These characteristics make it suitable for applications with higher power dissipation requirements.

Q: Are BZX85C51 series parts suitable replacements?

A: The BZX85C51-TAP and BZX85C51-TR maintain 51 V zener voltage and ±5% tolerance with 1.3 W power rating. Both feature AEC-Q101 automotive qualification and significantly lower reverse leakage at 500 nA. Operating temperature range is -55°C to 175°C. These parts are suitable for applications where automotive-grade qualification and lower leakage current are required. Temperature range limitation to -55°C minimum should be verified against application requirements.

Q: Why is the 1N4758A listed as a non-equivalent?

A: The 1N4758A features 56 V zener voltage, which differs from the 51 V specification of the main part. This 5 V difference represents a 9.8% deviation and is outside the ±5% tolerance band. Applications requiring precise 51 V regulation cannot use this part. Additionally, the 1N4758A is Obsolete product status.

Q: What packaging considerations apply to these substitutes?

A: All substitute parts use DO-204AL (DO-41) or equivalent axial through-hole packaging, which is mechanically compatible with the main part. The 1N5942BRLG uses axial packaging, which is also compatible with standard DO-41 footprints. Cut Tape (CT) packaging on some substitutes indicates tape-and-reel format for automated assembly; Bulk packaging indicates loose component format. Packaging format does not affect electrical compatibility or mechanical fit.

Q: Is RoHS3 compliance maintained across all substitutes?

A: All substitute parts listed are RoHS3 compliant and REACH unaffected, matching the compliance status of the main part 1N4757G R0G. This ensures regulatory compatibility for applications subject to RoHS3 requirements.

Q: Can ZPY51-TR be used in high-frequency applications?

A: The ZPY51-TR features the lowest impedance (45 Ohms) among all substitutes, which provides improved high-frequency performance characteristics. This lower impedance reduces voltage variation across frequency ranges. However, impedance specification alone does not determine high-frequency suitability; application-specific frequency response requirements must be evaluated independently.

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