SF31G-AP General Purpose Rectifier Diode Equivalent & Substitute Parts

Part Overview

The SF31G-AP is a general purpose rectifier diode manufactured by Micro Commercial Co, rated for 50V DC reverse voltage and 3A average rectified current in a DO-201AD axial through-hole package. This component is classified as "Not For New Designs," indicating it has reached end-of-life status. Identification of equivalent and substitute parts is necessary for maintenance, repair, and legacy system support where continued availability of the original part number cannot be assured.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	50	V
Current - Average Rectified (Io)	3	A
Voltage - Forward (Vf) (Max) @ If	950 mV @ 3 A	mV
Reverse Recovery Time (trr)	35	ns
Current - Reverse Leakage @ Vr	5	µA @ 50 V
Package / Case	DO-201AD, Axial	—
Mounting Type	Through Hole	—
Operating Temperature - Junction	-65°C ~ 150°C	°C
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the SF31G-AP is determined by strict equivalence across the following critical parameters:

Voltage Rating (Vr): 50V maximum DC reverse voltage
Current Rating (Io): 3A average rectified current
Forward Voltage (Vf): 950 mV maximum at 3A
Recovery Characteristics: Fast recovery with trr ≤ 35 ns
Reverse Leakage: 5 µA maximum at 50V
Package: DO-201AD axial through-hole configuration
Compliance: ROHS3 compliant, REACH unaffected

A substitute part must match or exceed all electrical specifications while maintaining identical mechanical compatibility. The SF31G A0G from Taiwan Semiconductor Corporation meets these criteria across all specified parameters.

Parameter Comparison

Parameter	SF31G-AP (Micro Commercial Co)	SF31G A0G (Taiwan Semiconductor)	Match Status
Voltage - DC Reverse (Vr) (Max)	50 V	50 V	Equivalent
Current - Average Rectified (Io)	3 A	3 A	Equivalent
Voltage - Forward (Vf) (Max) @ If	950 mV @ 3 A	950 mV @ 3 A	Equivalent
Speed	Fast Recovery ≤ 500ns, > 200mA (Io)	Fast Recovery ≤ 500ns, > 200mA (Io)	Equivalent
Reverse Recovery Time (trr)	35 ns	35 ns	Equivalent
Current - Reverse Leakage @ Vr	5 µA @ 50 V	5 µA @ 50 V	Equivalent
Capacitance @ Vr, F	50 pF @ 4V, 1MHz	80 pF @ 4V, 1MHz	Substitute Higher
Package / Case	DO-201AD, Axial	DO-201AD, Axial	Equivalent
Operating Temperature - Junction	-65°C ~ 150°C	-55°C ~ 150°C	Substitute Narrower
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Equivalent
Product Status	Not For New Designs	Active	Substitute Active

Engineering Selection Recommendations

The SF31G A0G from Taiwan Semiconductor Corporation is a direct electrical and mechanical substitute for the SF31G-AP. Both components are ROHS3 compliant and carry identical electrical specifications across voltage, current, and recovery characteristics.

The SF31G A0G holds active product status, ensuring continued availability and supply chain reliability compared to the SF31G-AP, which is designated "Not For New Designs." This status difference makes the SF31G A0G the preferred selection for applications requiring long-term component sourcing.

Two minor parameter differences exist:

Capacitance: The SF31G A0G exhibits 80 pF versus 50 pF in the original part. This higher capacitance does not degrade performance in standard rectification applications and may provide marginal benefits in high-frequency switching scenarios.
Operating Temperature Range: The SF31G A0G supports -55°C to 150°C versus -65°C to 150°C for the SF31G-AP. The narrower lower temperature limit is acceptable for applications operating above -55°C.

Both components are suitable for direct board-level substitution without circuit modification.

Frequently Asked Questions (FAQ)

Q: Can the SF31G A0G replace the SF31G-AP in existing designs?

A: Yes. The SF31G A0G is electrically and mechanically equivalent to the SF31G-AP. Both components share identical voltage ratings (50V), current ratings (3A), forward voltage characteristics (950 mV @ 3A), and recovery time specifications (35 ns). The DO-201AD axial package is identical, permitting direct substitution without PCB modification.

Q: What is the significance of the SF31G-AP being "Not For New Designs"?

A: This designation indicates the part has reached end-of-life status and is no longer recommended for new product development. Existing inventory may remain available, but long-term supply cannot be assured. The SF31G A0G, with active product status, provides a sustainable alternative for both legacy support and new applications.

Q: Does the higher capacitance of the SF31G A0G (80 pF vs. 50 pF) affect circuit performance?

A: The capacitance difference is not significant for standard rectification applications. In low-frequency power supply circuits, this parameter has minimal impact on circuit behavior. Applications operating at frequencies above 1 MHz should verify that the higher capacitance does not introduce unintended effects, though this is unlikely in typical rectifier applications.

Q: Is the narrower operating temperature range of the SF31G A0G (-55°C to 150°C vs. -65°C to 150°C) a limitation?

A: The SF31G A0G is suitable for applications operating within -55°C to 150°C. If your application requires operation below -55°C, the original SF31G-AP specification must be maintained. For standard industrial and commercial temperature ranges, the SF31G A0G is fully adequate.

Q: Are both parts RoHS compliant?

A: Yes. Both the SF31G-AP and SF31G A0G are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements for electronic components.

Q: What is the difference between the SF31G-AP and the cross-referenced parts 1N5400-E3/73 and 1N5400-E3/54?

A: The 1N5400-E3/73 and 1N5400-E3/54 are alternative part numbers associated with the SF31G A0G substitute. These designations may represent different manufacturer codes or regional variants. Verification with the component supplier is necessary to confirm exact equivalence and availability.

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