SF20DG-T Equivalent & Substitute Parts

Part Overview

The SF20DG-T is a general-purpose rectifier diode manufactured by Diodes Incorporated, rated for 200 V DC reverse voltage and 2 A average rectified current in a DO-15 through-hole axial package. The device features fast recovery characteristics with a reverse recovery time of 35 ns and operates across a junction temperature range of -65°C to 150°C.

This part is classified as obsolete. Equivalent and substitute parts are necessary to maintain design continuity and ensure component availability for new production runs, repairs, and system upgrades. Substitute diodes must match or exceed the electrical performance specifications while maintaining mechanical compatibility with existing PCB layouts and assembly processes.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	200	V
Current - Average Rectified (Io)	2	A
Voltage - Forward (Vf) (Max) @ If	950 mV @ 2 A	mV @ A
Speed Classification	Fast Recovery ≤ 500ns, > 200mA (Io)	—
Reverse Recovery Time (trr)	35	ns
Current - Reverse Leakage @ Vr	10	µA @ 200 V
Mounting Type	Through Hole	—
Package / Case	DO-204AC, DO-15, Axial	—
Operating Temperature - Junction	-65 to 150	°C
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the SF20DG-T is determined by the following critical electrical and mechanical parameters:

Mandatory Matching Criteria:

Voltage - DC Reverse (Vr) (Max): 200 V minimum
Current - Average Rectified (Io): 2 A minimum
Mounting Type: Through Hole
Package / Case: DO-15 or DO-204AC (axial configuration)

Performance Compatibility Criteria:

Speed Classification: Fast Recovery (≤ 500ns, > 200mA) or equivalent
Reverse Recovery Time (trr): 35 ns or lower
Forward Voltage (Vf): 950 mV to 1.3 V @ 2-3 A (acceptable range for general-purpose rectification)
Reverse Leakage Current: 10 µA or lower @ 200 V

Compliance Requirements:

RoHS3 Compliant
Operating Temperature Range: -55°C to 175°C minimum (covers or exceeds -65°C to 150°C)

Substitute parts are grouped into two categories: direct package equivalents (DO-15/DO-204AC axial) and alternative package options (SOD-57 axial, DO-41 axial) that maintain electrical performance within the specified parameters.

Parameter Comparison

Parameter	SF20DG-T	BYV27-200-TAP	BYV27-200-TR	FR203GP-AP	GPP20D-E3/54	MUR220G	MUR220RLG	SBYV27-200-E3/54	SBYV27-200-E3/73	SF24G-BP	STTH3R02QRL
Voltage - DC Reverse (Vr) (Max)	200 V	200 V	200 V	200 V	200 V	200 V	200 V	200 V	200 V	200 V	200 V
Current - Average Rectified (Io)	2 A	2 A	2 A	2 A	2 A	2 A	2 A	2 A	2 A	2 A	3 A
Voltage - Forward (Vf) (Max) @ If	950 mV @ 2 A	1.07 V @ 3 A	1.07 V @ 3 A	1.3 V @ 2 A	1.1 V @ 2 A	950 mV @ 2 A	950 mV @ 2 A	1.07 V @ 3 A	1.07 V @ 3 A	950 mV @ 2 A	1 V @ 3 A
Speed Classification	Fast Recovery ≤ 500ns	Fast Recovery ≤ 500ns	Fast Recovery ≤ 500ns	Fast Recovery ≤ 500ns	Standard Recovery >500ns	Fast Recovery ≤ 500ns	Fast Recovery ≤ 500ns	Fast Recovery ≤ 500ns	Fast Recovery ≤ 500ns	Fast Recovery ≤ 500ns	Fast Recovery ≤ 500ns
Reverse Recovery Time (trr)	35 ns	25 ns	25 ns	150 ns	—	35 ns	35 ns	15 ns	15 ns	35 ns	30 ns
Current - Reverse Leakage @ Vr	10 µA @ 200 V	1 µA @ 200 V	1 µA @ 200 V	5 µA @ 200 V	5 µA @ 200 V	2 µA @ 200 V	2 µA @ 200 V	5 µA @ 200 V	5 µA @ 200 V	5 µA @ 200 V	3 µA @ 200 V
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	DO-204AC, DO-15, Axial	SOD-57, Axial	SOD-57, Axial	DO-204AC, DO-15, Axial	DO-204AC, DO-15, Axial	DO-204AL, DO-41, Axial	DO-204AL, DO-41, Axial	DO-204AC, DO-15, Axial	DO-204AC, DO-15, Axial	DO-204AC, DO-15, Axial	DO-204AC, DO-15, Axial
Operating Temperature - Junction	-65 to 150°C	-55 to 175°C	-55 to 175°C	-55 to 150°C	-55 to 150°C	-65 to 175°C	-65 to 175°C	-55 to 150°C	-55 to 150°C	-65 to 150°C	—
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	—	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitutes (Direct Package Equivalents - DO-15/DO-204AC Axial):

The following parts provide direct mechanical and electrical compatibility with the SF20DG-T:

SBYV27-200-E3/54 and SBYV27-200-E3/73 (Vishay): These diodes match the DO-204AC (DO-15) package and exceed electrical performance with 15 ns reverse recovery time, lower reverse leakage (5 µA), and active product status. Both are ROHS3 compliant and suitable for immediate substitution.
SF24G-BP (Micro Commercial Co): Maintains identical package configuration and electrical characteristics to the SF20DG-T, with active product status and ROHS3 compliance.
FR203GP-AP (Micro Commercial Co): Provides DO-15 package compatibility with 200 V / 2 A ratings. Note: Reverse recovery time is 150 ns (slower than SF20DG-T), suitable for applications not requiring fast recovery performance.
GPP20D-E3/54 (Vishay): Offers DO-204AC package compatibility with standard recovery characteristics (>500ns). Appropriate for general-purpose rectification where fast recovery is not required.

Secondary Substitutes (Alternative Axial Packages - DO-41):

MUR220G and MUR220RLG (onsemi): These diodes use the DO-204AL (DO-41) axial package, which differs physically from DO-15 but maintains identical electrical specifications (200 V / 2 A, 35 ns trr, 950 mV Vf). Both are active, ROHS3 compliant, and feature the SWITCHMODE™ series designation. PCB layout modification is required for package substitution.

Alternative Package Substitutes (SOD-57 Axial):

BYV27-200-TAP and BYV27-200-TR (Vishay): These avalanche diodes use the SOD-57 axial package with superior electrical performance (25 ns trr, 1 µA reverse leakage). Both are active and ROHS3 compliant. Physical package dimensions differ from DO-15; PCB layout modification is necessary.

Higher Current Rating Option:

STTH3R02QRL (STMicroelectronics): Rated for 3 A average rectified current (exceeds 2 A requirement) in DO-15 package. Provides design margin for applications with potential current increases. Active product status and ROHS3 compliant.

Selection Criteria:

Choose substitutes based on the following priorities:

Package Compatibility: If PCB layout cannot be modified, select from SBYV27-200-E3/54, SBYV27-200-E3/73, SF24G-BP, FR203GP-AP, or STTH3R02QRL (all DO-15/DO-204AC).
Performance Requirements: For fast recovery applications (switching power supplies, high-frequency rectification), select SBYV27-200-E3/54, SBYV27-200-E3/73, MUR220G, MUR220RLG, BYV27-200-TAP, or BYV27-200-TR.
Product Availability: MUR220RLG offers the highest inventory (265,300 pcs) among active substitutes.
Compliance and Certification: All recommended substitutes are ROHS3 compliant and suitable for regulated applications.

Frequently Asked Questions (FAQ)

Q: Can I use STTH3R02QRL as a direct replacement for SF20DG-T?

A: Yes. STTH3R02QRL is rated for 3 A average rectified current, which exceeds the SF20DG-T's 2 A specification. Both use the DO-15 package. The higher current rating provides design margin without compromising compatibility. Electrical characteristics (200 V reverse voltage, fast recovery, 30 ns trr) are within acceptable parameters.

Q: What is the difference between DO-15 and DO-204AC packages?

A: DO-15 and DO-204AC are equivalent designations for the same axial through-hole package. Both refer to a cylindrical diode body with axial leads. These terms are used interchangeably in component specifications.

Q: Can I substitute MUR220G (DO-41 package) for SF20DG-T (DO-15 package)?

A: Electrically, yes. MUR220G meets all electrical requirements (200 V, 2 A, 35 ns trr, 950 mV Vf). However, the DO-41 package has different physical dimensions than DO-15. PCB layout modification is required to accommodate the different lead spacing and body size. Mechanical compatibility cannot be assumed without design review.

Q: Why does FR203GP-AP have a 150 ns reverse recovery time when SF20DG-T specifies 35 ns?

A: FR203GP-AP uses standard recovery diode technology, while SF20DG-T uses fast recovery technology. The longer reverse recovery time (150 ns) means FR203GP-AP is slower to block reverse current. This is acceptable for general-purpose rectification but not suitable for high-frequency switching applications. Select FR203GP-AP only if application requirements do not mandate fast recovery performance.

Q: Are BYV27-200-TAP and BYV27-200-TR interchangeable?

A: Yes. Both are identical avalanche diodes rated for 200 V / 2 A with 25 ns reverse recovery time. The difference is packaging: BYV27-200-TAP is supplied in cut tape (CT), while BYV27-200-TR is supplied in tape and reel (TR). Electrical performance and SOD-57 package are identical. Selection depends on procurement and assembly requirements.

Q: What does "Fast Recovery ≤ 500ns, > 200mA (Io)" mean?

A: This specification indicates the diode is classified as fast recovery when reverse recovery time is 500 nanoseconds or less at reverse currents exceeding 200 milliamps. This classification is relevant for switching applications where rapid current blocking is required. Standard recovery diodes (>500ns) are suitable for linear rectification but not for high-frequency switching.

Q: Can I use GPP20D-E3/54 in a switching power supply application?

A: GPP20D-E3/54 has standard recovery characteristics (>500ns reverse recovery time), making it unsuitable for switching power supplies that require fast recovery diodes. Use SBYV27-200-E3/54, SBYV27-200-E3/73, MUR220G, MUR220RLG, BYV27-200-TAP, or BYV27-200-TR instead.

Q: What is the significance of reverse leakage current specifications?

A: Reverse leakage current (measured at maximum reverse voltage) indicates the quality of the diode's reverse blocking capability. Lower leakage current (1-5 µA) indicates better blocking performance and lower power dissipation in reverse bias. SF20DG-T specifies 10 µA, while most substitutes offer 1-5 µA, representing improved performance.

Q: Is REACH compliance important for component selection?

A: REACH compliance indicates the component meets European chemical substance regulations. Most recommended substitutes are REACH Unaffected or compliant. For applications subject to European regulatory requirements, verify REACH status during final selection. All listed substitutes meet or exceed regulatory requirements.

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