SB350 Schottky Diode Equivalent & Substitute Parts

Part Overview

The SB350 is a Schottky rectifier diode manufactured by onsemi, rated for 50 V DC reverse voltage and 3 A average rectified current in a DO-201AD through-hole axial package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The SB350 operates across a junction temperature range of -65°C to 125°C and exhibits fast recovery characteristics suitable for high-frequency rectification applications.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	50	V
Current - Average Rectified (Io)	3	A
Voltage - Forward (Vf) (Max) @ If	740 mV @ 3 A	mV
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)	ns
Current - Reverse Leakage @ Vr	500	µA @ 50 V
Capacitance @ Vr, F	180	pF @ 4V, 1MHz
Mounting Type	Through Hole	-
Package / Case	DO-201AD, Axial	-
Operating Temperature - Junction	-65 to 125	°C
Technology	Schottky	-
RoHS Status	ROHS3 Compliant	-

Substitute Part Grouping Explanation

Substitution of the SB350 is determined by the following critical parameters:

Primary Substitution Criteria:

Voltage rating (Vr): Minimum 50 V required; higher ratings are acceptable
Current rating (Io): Minimum 3 A required; higher ratings are acceptable
Package type: DO-201AD through-hole axial required for mechanical compatibility
Technology: Schottky diode type required
Speed: Fast recovery characteristic (≤ 500ns, > 200mA) required

Secondary Compatibility Factors:

Forward voltage (Vf): Values within ±100 mV of 740 mV are acceptable
Reverse leakage current: Values up to 2 mA acceptable
Operating temperature range: Minimum -50°C to 125°C acceptable
RoHS compliance: ROHS3 compliance preferred but not mandatory for obsolete part replacement

Substitute parts are grouped into two categories:

Category A - Direct Voltage/Current Match (50V, 3A): Parts maintaining exact 50 V and 3 A ratings in DO-201AD package.

Category B - Reduced Voltage Rating (40V, 3A): Parts with 40 V rating suitable for applications where 50 V reverse voltage is not required; current rating remains at 3 A.

Category C - Enhanced Current Rating (50V, 3.3A or higher): Parts with 50 V rating and current ratings exceeding 3 A, providing design margin.

Parameter Comparison

Part Number	Manufacturer	Vr (Max)	Io	Vf @ 3A	Package	Status	RoHS
SB350	onsemi	50 V	3 A	740 mV	DO-201AD	Obsolete	ROHS3
1N5822-AP	Micro Commercial Co	40 V	3 A	525 mV	DO-201AD	Active	-
31DQ05	SMC Diode Solutions	50 V	3.3 A	620 mV	DO-201AD	Active	ROHS3
SR304-AP	Micro Commercial Co	40 V	3 A	500 mV	DO-201AD	Active	-
SR304-BP	Micro Commercial Co	40 V	3 A	500 mV	DO-201AD	Active	-
SR304-TP	Micro Commercial Co	40 V	3 A	500 mV	DO-201AD	Active	-
SR305-TP	Micro Commercial Co	50 V	3 A	720 mV	DO-201AD	Not For New Designs	ROHS3
SR805HA0G	Taiwan Semiconductor Corporation	50 V	8 A	700 mV	DO-201AD	Active	ROHS3

Engineering Selection Recommendations

For Direct Replacement (50V, 3A Rating Required):

SR305-TP is the closest electrical equivalent to SB350, maintaining 50 V reverse voltage and 3 A current rating in identical DO-201AD packaging. Forward voltage of 720 mV is within acceptable tolerance of the original 740 mV specification. However, SR305-TP carries a "Not For New Designs" status, indicating limited long-term availability. This part is suitable for legacy system maintenance and repair applications only.

31DQ05 provides an active production alternative with 50 V rating and enhanced 3.3 A current capability. Forward voltage of 620 mV is lower than the original specification, reducing power dissipation. ROHS3 compliance matches the original part. This part is recommended for new designs requiring 50 V performance.

For Cost-Optimized Replacement (40V Rating Acceptable):

SR304-AP, SR304-BP, and SR304-TP are functionally identical parts from Micro Commercial Co, all rated 40 V and 3 A in DO-201AD packaging. These parts are suitable for applications where the circuit design does not require the full 50 V reverse voltage margin. Forward voltage of 500 mV is significantly lower than the original, improving efficiency. All three variants are in active production with adequate inventory.

1N5822-AP from Micro Commercial Co offers similar 40 V, 3 A performance with the lowest forward voltage (525 mV) among 40 V alternatives. This part is suitable for cost-sensitive applications where 50 V rating is not required.

For Enhanced Current Margin:

SR805HA0G provides 50 V rating with 8 A current capacity, offering substantial design margin for applications requiring higher current handling. This part includes AEC-Q101 automotive qualification and operates to 150°C junction temperature. Suitable for demanding industrial and automotive applications.

Compliance Considerations:

Parts with ROHS3 compliance (SB350, 31DQ05, SR305-TP, SR805HA0G) are preferred for new designs and regulated applications. SR304 series and 1N5822-AP parts lack explicit RoHS certification in provided data; verify compliance requirements with procurement before selection.

Frequently Asked Questions (FAQ)

Q: Can SR304 series parts (40V rating) replace SB350 (50V rating) in existing designs?

A: SR304 series substitution is valid only if the circuit design does not depend on the full 50 V reverse voltage margin. Review the application schematic to confirm maximum reverse voltage stress does not exceed 40 V under normal and fault conditions. If 50 V rating is required, use SR305-TP or 31DQ05 instead.

Q: What is the difference between SR304-AP, SR304-BP, and SR304-TP?

A: All three variants are electrically identical Schottky diodes with 40 V, 3 A ratings in DO-201AD packaging. The suffix letters indicate different packaging or tape configurations (AP, BP, TP). Selection depends on procurement format requirements. Electrical performance is equivalent across all three variants.

Q: Is 31DQ05 a direct replacement for SB350?

A: 31DQ05 is a functional equivalent with matching 50 V rating and DO-201AD package. The 3.3 A current rating exceeds the original 3 A specification, providing design margin. Forward voltage of 620 mV is lower than SB350's 740 mV, reducing power dissipation. 31DQ05 is in active production with ROHS3 compliance, making it suitable for new designs.

Q: Why is SR305-TP marked "Not For New Designs"?

A: This status indicates the manufacturer is transitioning away from this part number. While SR305-TP is electrically equivalent to SB350 (50V, 3A, DO-201AD), it should be used only for legacy system repairs. For new designs, select 31DQ05 or SR805HA0G instead.

Q: Can SR805HA0G be used as a drop-in replacement for SB350?

A: SR805HA0G is mechanically and electrically compatible (50V, DO-201AD package, fast recovery). The 8 A current rating far exceeds the 3 A requirement, providing substantial margin. Forward voltage of 700 mV is comparable to SB350. This part is suitable for replacement; however, the higher current rating may be unnecessary for applications designed for 3 A operation.

Q: What is the impact of forward voltage differences between substitute parts?

A: Forward voltage differences directly affect power dissipation and heat generation. Lower Vf values (such as SR304 series at 500 mV versus SB350 at 740 mV) reduce power loss and operating temperature. Higher Vf values increase dissipation. Verify thermal design margins remain adequate when substituting parts with significantly different forward voltage specifications.

Q: Are all substitute parts available in the same packaging format?

A: All listed substitute parts use DO-201AD through-hole axial packaging, matching SB350 mechanical compatibility. Packaging variants (Cut Tape, Bulk, Tape & Reel) affect procurement and assembly processes but do not change electrical performance. Confirm packaging format availability with your supplier before finalizing part selection.

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