FR101 Equivalent & Substitute Parts

Part Overview

The FR101 is a general-purpose rectifier diode rated for 50 V DC reverse voltage and 1 A average rectified current in a DO-41 through-hole axial package. This diode is classified as obsolete, making equivalent and substitute parts necessary for ongoing production and maintenance applications. The FR101 features fast recovery characteristics with a reverse recovery time of 150 ns, suitable for standard rectification circuits requiring moderate switching speeds.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	50	V
Current - Average Rectified (Io)	1	A
Voltage - Forward (Vf) (Max) @ If	1.3	V @ 1 A
Speed Classification	Fast Recovery ≤ 500ns, > 200mA (Io)	-
Reverse Recovery Time (trr)	150	ns
Current - Reverse Leakage @ Vr	5	µA @ 50 V
Mounting Type	Through Hole	-
Package / Case	DO-204AL, DO-41, Axial	-
Operating Temperature - Junction	-65 to 150	°C

Substitute Part Grouping Explanation

Substitution of the FR101 is determined by strict equivalence across the following electrical and mechanical parameters:

Primary Substitution Criteria:

Voltage - DC Reverse (Vr) (Max): 50 V minimum
Current - Average Rectified (Io): 1 A minimum
Mounting Type: Through Hole
Package / Case: DO-204AL, DO-41, or Axial compatible

Secondary Compatibility Factors:

Forward voltage (Vf) at rated current
Reverse recovery time (trr) and speed classification
Reverse leakage current
Operating temperature range

Substitute parts are grouped into two categories:

Direct Equivalents (FR101G, FR101G A0G, FR101G B0G): These parts maintain identical electrical ratings, fast recovery speed characteristics (150 ns trr), and forward voltage specifications. They are manufactured by Taiwan Semiconductor Corporation and are active products with RoHS3 compliance.

Functional Equivalents (1N4001G, 1N4001RLG, UF1AHA0G): These parts meet or exceed the primary electrical requirements (50 V, 1 A) and package compatibility but may differ in secondary parameters such as recovery speed classification or forward voltage. The 1N4001G and 1N4001RLG employ standard recovery characteristics (>500ns), while UF1AHA0G features automotive-grade qualification with faster recovery (50 ns trr).

Parameter Comparison

Part Number	Manufacturer	Product Status	Vr (Max) [V]	Io [A]	Vf (Max) @ 1A [V]	Speed Classification	trr [ns]	Ir @ Vr [µA]	Temp Range [°C]	RoHS Status
FR101	SMC Diode Solutions	Obsolete	50	1	1.3	Fast Recovery ≤ 500ns	150	5 @ 50V	-65 to 150	Not Specified
FR101G	Taiwan Semiconductor Corporation	Active	50	1	1.3	Fast Recovery ≤ 500ns	150	5 @ 50V	-55 to 150	ROHS3 Compliant
FR101G A0G	Taiwan Semiconductor Corporation	Active	50	1	1.3	Fast Recovery ≤ 500ns	150	5 @ 50V	-55 to 150	ROHS3 Compliant
FR101G B0G	Taiwan Semiconductor Corporation	Active	50	1	1.3	Fast Recovery ≤ 500ns	150	5 @ 50V	-55 to 150	ROHS3 Compliant
UF1AHA0G	Taiwan Semiconductor Corporation	Active	50	1	1.0	Fast Recovery ≤ 500ns	50	5 @ 50V	-55 to 150	ROHS3 Compliant
1N4001G	Taiwan Semiconductor Corporation	Active	50	1	1.0	Standard Recovery >500ns	Not Specified	5 @ 50V	-55 to 150	ROHS3 Compliant
1N4001RLG	onsemi	Not For New Designs	50	1	1.1	Standard Recovery >500ns	Not Specified	10 @ 50V	-65 to 175	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Preferred): FR101G, FR101G A0G, and FR101G B0G are the primary substitutes for the obsolete FR101. These parts are manufactured by Taiwan Semiconductor Corporation, maintain active product status, and provide identical electrical specifications including fast recovery characteristics. All three variants are RoHS3 compliant and suitable for new designs. The choice between these three variants depends on packaging requirements (Tape & Reel versus bulk) and inventory availability.

For Functional Substitution (When Direct Equivalents Unavailable): UF1AHA0G is suitable when fast recovery performance and automotive-grade qualification are required. This part features a faster reverse recovery time (50 ns) and lower forward voltage (1.0 V), making it compatible with applications requiring enhanced switching performance. UF1AHA0G carries AEC-Q101 automotive qualification and is RoHS3 compliant.

1N4001G and 1N4001RLG are functional alternatives when standard recovery speed is acceptable. Both parts meet the 50 V, 1 A electrical requirements and through-hole package compatibility. However, 1N4001RLG is classified as "Not For New Designs" by onsemi, limiting its use to legacy system maintenance. 1N4001G remains an active product and is the preferred choice between these two options.

Compliance Considerations: All recommended substitutes are RoHS3 compliant and REACH unaffected. The FR101 original part does not specify RoHS status; substitution with RoHS3-compliant alternatives ensures regulatory compliance for new production and updated designs.

Frequently Asked Questions (FAQ)

Q: Can FR101G directly replace the obsolete FR101? A: Yes. FR101G is a direct electrical and mechanical equivalent. Both parts share identical ratings for reverse voltage (50 V), average rectified current (1 A), forward voltage (1.3 V @ 1 A), and fast recovery characteristics (150 ns trr). The primary difference is product status: FR101G is active and RoHS3 compliant, while FR101 is obsolete.

Q: What is the difference between FR101G, FR101G A0G, and FR101G B0G? A: These three variants are electrically identical and differ only in packaging and distribution format. FR101G is supplied in Tape & Reel (TR) packaging, while FR101G A0G and FR101G B0G are supplied in bulk format. All three maintain the same electrical specifications and are suitable for direct substitution.

Q: Can 1N4001G replace FR101? A: 1N4001G is a functional substitute that meets the primary electrical requirements (50 V, 1 A, through-hole DO-41 package). However, it differs in speed classification: 1N4001G uses standard recovery (>500ns) compared to FR101's fast recovery (150 ns trr). This substitution is acceptable for applications where switching speed is not critical.

Q: Is UF1AHA0G suitable for FR101 replacement? A: UF1AHA0G is compatible with FR101 from an electrical and package perspective (50 V, 1 A, DO-41 through-hole). UF1AHA0G offers superior performance characteristics: faster recovery time (50 ns versus 150 ns) and lower forward voltage (1.0 V versus 1.3 V). UF1AHA0G includes automotive-grade qualification (AEC-Q101), making it suitable for applications requiring enhanced reliability.

Q: Why is 1N4001RLG marked "Not For New Designs"? A: 1N4001RLG is a legacy product from onsemi. While it meets the electrical requirements for FR101 substitution, its "Not For New Designs" status indicates that onsemi recommends using alternative active products for new applications. For maintenance of existing systems, 1N4001RLG remains functionally compatible.

Q: What are the package compatibility considerations? A: All substitute parts use DO-204AL, DO-41, or axial package designations, which are mechanically and electrically compatible. The FR101 and all substitutes are through-hole components suitable for PCB mounting in axial orientation. Packaging format (Tape & Reel versus bulk) affects distribution and handling but not electrical performance.

Q: Are all substitute parts RoHS3 compliant? A: All recommended substitute parts (FR101G, FR101G A0G, FR101G B0G, UF1AHA0G, 1N4001G, and 1N4001RLG) are RoHS3 compliant. The original FR101 does not specify RoHS status. Substitution with RoHS3-compliant alternatives ensures compliance with current environmental regulations.

Q: What is the temperature range difference between FR101 and its substitutes? A: The original FR101 operates from -65°C to 150°C. Most substitutes (FR101G, FR101G A0G, FR101G B0G, UF1AHA0G, 1N4001G) operate from -55°C to 150°C, providing a slightly narrower low-temperature range. 1N4001RLG extends to -65°C to 175°C. For applications requiring the full -65°C lower limit, 1N4001RLG is the only substitute maintaining this specification.

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