1N5821 Schottky Diode Equivalent & Substitute Parts

Part Overview

The 1N5821 is a 30 V, 3 A Schottky rectifier diode in DO-201AD axial through-hole packaging. This component is classified as obsolete in its original onsemi configuration, necessitating identification of active equivalent and substitute parts from alternative manufacturers. Schottky diodes in this voltage and current class are used in power supply rectification, reverse polarity protection, and high-frequency switching applications where fast recovery characteristics are required.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) Maximum	30	V
Current - Average Rectified (Io)	3	A
Voltage - Forward (Vf) Maximum @ If	500	mV @ 3 A
Speed - Fast Recovery	≤ 500	ns, > 200mA (Io)
Current - Reverse Leakage @ Vr	500	µA @ 30 V
Mounting Type	Through Hole	—
Package / Case	DO-201AD, Axial	—
Operating Temperature - Junction	-65 to 125	°C
Technology	Schottky	—

Substitute Part Grouping Explanation

Substitution of the 1N5821 Schottky diode is determined by the following critical parameters:

Primary Substitution Criteria:

Voltage - DC Reverse (Vr) rating of 30 V or higher
Current - Average Rectified (Io) rating of 3 A or higher
Fast Recovery technology (≤ 500 ns, > 200 mA)
Through-hole mounting configuration
DO-201AD or equivalent axial package compatibility

Substitution Categories:

Direct Equivalents maintain all primary electrical specifications and identical packaging. These parts are pin-compatible and functionally interchangeable without circuit modification.

Similar Equivalents meet or exceed all primary electrical specifications but may have minor variations in secondary parameters such as reverse leakage current, capacitance, or operating temperature range. These parts are functionally compatible for the same applications.

Functional Alternatives exceed the primary electrical specifications (higher voltage or current ratings) or employ different packaging (surface mount versus through-hole). These parts require circuit board redesign or adapter solutions and are not direct drop-in replacements.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Product Status	Vr (Max) V	Io (A)	Vf (Max) mV @ If	Reverse Leakage µA @ 30V	Package / Case	Tj (°C)	Substitution Type
1N5821	onsemi	Obsolete	30	3	500 @ 3A	500	DO-201AD, Axial	-65 to 125	Reference Part
1N5821RLG	onsemi	Active	30	3	500 @ 3A	2000	DO-201AA, DO-27, Axial	-65 to 125	Direct Equivalent
1N5821-AP	Micro Commercial Co	Active	30	3	500 @ 3A	500	DO-201AD, Axial	-55 to 125	Direct Equivalent
1N5821-BP	Micro Commercial Co	Active	30	3	500 @ 3A	500	DO-201AD, Axial	-55 to 125	Direct Equivalent
1N5821	Microchip Technology	Active	30	3	500 @ 3A	100	B, Axial	-65 to 125	Similar Equivalent
1N5821-TP	Micro Commercial Co	Active	30	3	500 @ 3A	500	DO-201AD, Axial	-55 to 125	Direct Equivalent
31DQ03	SMC Diode Solutions	Active	30	3.3	570 @ 3A	1000	DO-201AD, Axial	-40 to 150	Similar Equivalent
SB330-E3/54	Vishay General Semiconductor - Diodes Division	Active	30	3	490 @ 3A	500	DO-201AD, Axial	-65 to 125	Direct Equivalent
SB330_R2_00001	Panjit International Inc.	Active	30	3	500 @ 3A	200	DO-201AD, Axial	-55 to 125	Direct Equivalent
ZHCS750TA	Diodes Incorporated	Active	40	0.75	490 @ 0.75A	100	SOT-23-3	—	Functional Alternative

Engineering Selection Recommendations

For Direct Replacement (No Circuit Modification Required):

Select from the following active parts that maintain DO-201AD axial through-hole packaging and 30 V / 3 A specifications:

1N5821-AP (Micro Commercial Co): Active status, identical electrical specifications, DO-201AD package, ROHS3 compliant. Operating temperature range -55°C to 125°C.
1N5821-BP (Micro Commercial Co): Active status, identical electrical specifications, DO-201AD package, ROHS3 compliant. Operating temperature range -55°C to 125°C.
1N5821-TP (Micro Commercial Co): Active status, identical electrical specifications, DO-201AD package, ROHS3 compliant, Cut Tape packaging. Operating temperature range -55°C to 125°C.
SB330-E3/54 (Vishay General Semiconductor - Diodes Division): Active status, 30 V / 3 A specifications, DO-201AD package, ROHS3 compliant. Forward voltage 490 mV @ 3 A. Operating temperature range -65°C to 125°C.
SB330_R2_00001 (Panjit International Inc.): Active status, 30 V / 3 A specifications, DO-201AD package, ROHS3 compliant, Tape & Reel packaging. Operating temperature range -55°C to 125°C.

For Applications Requiring Extended Current Capability:

31DQ03 (SMC Diode Solutions): Active status, 30 V / 3.3 A specifications, DO-201AD package, ROHS3 compliant. Extended operating temperature range -40°C to 150°C. Forward voltage 570 mV @ 3 A. Suitable for applications requiring higher current margin.

For Alternative Packaging (Surface Mount):

ZHCS750TA (Diodes Incorporated): Active status, 40 V / 750 mA specifications, SOT-23-3 surface mount package, ROHS3 compliant. This part is not a direct replacement and requires circuit board redesign. Suitable only for new designs or boards with surface mount capability.

For Extended Temperature Range:

1N5821RLG (onsemi): Active status, 30 V / 3 A specifications, DO-201AA/DO-27 axial package, ROHS3 compliant. Operating temperature range -65°C to 125°C. Package variant from original manufacturer.

All recommended parts are ROHS3 compliant and REACH unaffected, meeting current regulatory requirements.

Frequently Asked Questions (FAQ)

Q: Can I use 1N5821-AP or 1N5821-BP as direct replacements for the obsolete 1N5821?

A: Yes. Both parts are manufactured by Micro Commercial Co, maintain identical 30 V / 3 A electrical specifications, use DO-201AD axial through-hole packaging, and are ROHS3 compliant. The primary difference is operating temperature range (-55°C to 125°C versus -65°C to 125°C for the original). Verify your application's temperature requirements before selection.

Q: What is the difference between 1N5821-TP and 1N5821-AP?

A: Both parts are manufactured by Micro Commercial Co with identical electrical specifications (30 V / 3 A, DO-201AD package). The difference is packaging format: 1N5821-TP is supplied in Cut Tape (CT) format, while 1N5821-AP is supplied in Bulk format. Electrical performance is identical.

Q: Can I substitute the SB330-E3/54 for the 1N5821?

A: Yes. The SB330-E3/54 is manufactured by Vishay and maintains identical 30 V / 3 A electrical specifications with DO-201AD axial through-hole packaging. Forward voltage is 490 mV @ 3 A (compared to 500 mV for the 1N5821), which is a minor improvement. Operating temperature range is -65°C to 125°C. This part is ROHS3 compliant.

Q: Is the 31DQ03 a suitable replacement?

A: The 31DQ03 is functionally compatible but not identical. It provides higher current capability (3.3 A versus 3 A) and extended operating temperature range (-40°C to 150°C). Forward voltage is 570 mV @ 3 A, which is higher than the 1N5821 (500 mV). Use this part only if your application requires the additional current margin or extended temperature range.

Q: Why is the ZHCS750TA listed as a substitute if it has different specifications?

A: The ZHCS750TA is listed as a functional alternative, not a direct replacement. It uses surface mount SOT-23-3 packaging instead of through-hole DO-201AD, and has lower current rating (750 mA versus 3 A). This part is suitable only for new circuit designs with surface mount capability or applications with lower current requirements.

Q: What does "Product Status: Active" mean?

A: Active status indicates the part is currently manufactured and available from the supplier. The original 1N5821 from onsemi is classified as Obsolete, meaning it is no longer manufactured. All recommended substitutes have Active status, ensuring long-term availability.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed in this document are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements for electronic components.

Q: Can I use 1N5821RLG as a replacement?

A: Yes. The 1N5821RLG is manufactured by onsemi (the original manufacturer) with identical 30 V / 3 A electrical specifications and axial through-hole packaging. The package designation is DO-201AA/DO-27 instead of DO-201AD, but these are mechanically and electrically compatible. Operating temperature range is -65°C to 125°C.

Q: What is the difference between reverse leakage current values across substitute parts?

A: Reverse leakage current varies among manufacturers (100 µA to 2000 µA @ 30 V). Lower reverse leakage is generally preferable for low-power applications. For most power supply and rectification applications, these variations are not critical. Verify your application's leakage requirements if operating in low-current or high-impedance circuits.

Q: Can I mix different substitute parts in the same circuit?

A: Yes, provided all parts meet the minimum electrical specifications for your application (30 V reverse voltage, 3 A average rectified current, fast recovery ≤ 500 ns). However, for consistency and predictability, use the same part number throughout a design.

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