SD103C-T Schottky Diode Equivalent & Substitute Parts

Part Overview

The SD103C-T is a Schottky rectifier diode manufactured by Diodes Incorporated, rated for 20 V DC reverse voltage and 350 mA average rectified current in a through-hole DO-35 package. This part is classified as obsolete, necessitating identification of equivalent and substitute components for ongoing design requirements and production continuity. Substitute parts are selected based on matching or exceeding electrical performance parameters while maintaining functional compatibility within circuit applications.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	20	V
Current - Average Rectified (Io)	350	mA
Voltage - Forward (Vf) (Max) @ If	600 mV @ 200 mA	mV @ mA
Reverse Recovery Time (trr)	10	ns
Current - Reverse Leakage @ Vr	5 µA @ 10 V	µA @ V
Capacitance @ Vr, F	50 pF @ 0V, 1MHz	pF @ V, MHz
Mounting Type	Through Hole	—
Package / Case	DO-204AH, DO-35, Axial	—
Operating Temperature - Junction (Max)	125	°C
Technology	Schottky	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the SD103C-T is determined by the following critical parameters:

Electrical Compatibility Criteria:

Voltage - DC Reverse (Vr) rating must equal or exceed 20 V
Current - Average Rectified (Io) must equal or exceed 350 mA
Voltage - Forward (Vf) characteristics must be compatible with circuit design
Reverse Recovery Time (trr) must support fast recovery switching requirements
Technology must remain Schottky for consistent diode characteristics

Mechanical Compatibility Criteria:

Mounting type and package footprint determine physical substitutability
Through-hole DO-35 packages are directly interchangeable
Surface-mount SOD-123 packages require circuit board redesign

Compliance Criteria:

RoHS3 compliance preferred for new designs
REACH status consideration for supply chain continuity

Substitute parts are grouped into two categories: direct electrical equivalents with package variations and functional alternatives with modified electrical ratings.

Parameter Comparison

Part Number	Manufacturer	Vr (Max) [V]	Io [mA]	Vf (Max) @ If [mV @ mA]	trr [ns]	Package	Mounting Type	Product Status	RoHS Status
SD103C-T	Diodes Incorporated	20	350	600 @ 200	10	DO-35	Through Hole	Obsolete	ROHS3 Compliant
SD103BW-7-F	Diodes Incorporated	30	350	600 @ 200	10	SOD-123	Surface Mount	Active	ROHS3 Compliant
SD103CW-7-F	Diodes Incorporated	20	350	600 @ 200	10	SOD-123	Surface Mount	Active	ROHS3 Compliant
1N5712-1	Microchip Technology	20	75	1000 @ 35	—	DO-35	Through Hole	Active	RoHS non-compliant
1N6857-1	Microchip Technology	20	150	750 @ 35	—	DO-35	Through Hole	Active	RoHS non-compliant
BAT42	STMicroelectronics	30	200	1000 @ 200	5	DO-35	Through Hole	Active	ROHS3 Compliant
BAT48	STMicroelectronics	40	350	750 @ 200	—	DO-35	Through Hole	Active	ROHS3 Compliant
DSB0.2A20	Microchip Technology	20	200	500 @ 200	—	DO-35	Through Hole	Active	RoHS non-compliant
DSB0.2A40	Microchip Technology	20	200	510 @ 200	—	DO-35	Through Hole	Active	RoHS non-compliant
DSB0.5A20	Microchip Technology	20	500	650 @ 500	—	DO-35	Through Hole	Active	RoHS non-compliant

Engineering Selection Recommendations

Direct Electrical and Mechanical Equivalents (No Circuit Redesign Required):

The SD103CW-7-F provides identical electrical specifications (20 V, 350 mA, 600 mV forward voltage, 10 ns recovery time) with active product status and ROHS3 compliance. This part requires circuit board redesign due to SOD-123 surface-mount packaging versus the through-hole DO-35 of the original SD103C-T.

The BAT48 (STMicroelectronics) maintains through-hole DO-35 packaging and exceeds current rating (350 mA) with higher voltage rating (40 V). Forward voltage is 750 mV at 200 mA, representing a 150 mV increase. This part is active and ROHS3 compliant.

Functional Alternatives with Current Derating:

The 1N5712-1 and 1N6857-1 (Microchip Technology) maintain through-hole DO-35 packaging and 20 V voltage rating but provide reduced current capacity (75 mA and 150 mA respectively). These parts are suitable only for applications where the 350 mA current requirement can be reduced. Both are RoHS non-compliant.

The DSB0.5A20 (Microchip Technology) provides through-hole DO-35 packaging with 20 V rating and exceeds current capacity (500 mA). Forward voltage is 650 mV at 500 mA. This part is RoHS non-compliant.

Compliance Considerations:

For new designs requiring RoHS3 compliance, SD103CW-7-F or BAT48 are preferred. For legacy systems where RoHS compliance is not mandated, DSB0.5A20 offers superior current handling in the same package.

Frequently Asked Questions (FAQ)

Q: Can SD103CW-7-F directly replace SD103C-T without circuit modification?

A: SD103CW-7-F provides identical electrical specifications but uses SOD-123 surface-mount packaging instead of through-hole DO-35. Circuit board redesign is required. No electrical modification is necessary.

Q: What is the primary difference between SD103BW-7-F and SD103CW-7-F?

A: Both are surface-mount SOD-123 packages with identical current and forward voltage ratings. SD103BW-7-F has a 30 V reverse voltage rating, while SD103CW-7-F matches the original 20 V rating. For applications with 20 V maximum supply voltage, SD103CW-7-F is the appropriate selection.

Q: Is BAT48 a suitable replacement for through-hole applications?

A: Yes. BAT48 maintains through-hole DO-35 packaging and provides 350 mA current capacity matching the original specification. The 40 V reverse voltage rating exceeds the 20 V requirement, and forward voltage is 750 mV at 200 mA compared to 600 mV for the SD103C-T. This represents acceptable performance margin for most applications.

Q: Why do 1N5712-1 and 1N6857-1 have lower current ratings?

A: These parts are classified as small-signal Schottky diodes with maximum current ratings of 75 mA and 150 mA respectively, compared to 350 mA for the SD103C-T. They are suitable only for low-current applications and cannot replace the original part in high-current circuits.

Q: What is the significance of RoHS compliance status?

A: ROHS3-compliant parts (SD103CW-7-F, BAT48) meet European Union restrictions on hazardous substances and are required for products sold in regulated markets. RoHS non-compliant parts (1N5712-1, 1N6857-1, DSB series) may be restricted or prohibited depending on end-use application and geographic market.

Q: Can DSB0.5A20 be used in place of SD103C-T?

A: DSB0.5A20 provides through-hole DO-35 packaging with 20 V rating and 500 mA current capacity, exceeding the 350 mA requirement. Forward voltage is 650 mV at 500 mA. This part is electrically compatible but is RoHS non-compliant. Use is restricted to applications where RoHS compliance is not required.

Q: What does "Fast Recovery" mean in the speed specification?

A: Fast Recovery indicates reverse recovery time of 10 nanoseconds or less for currents exceeding 200 mA. This specification applies to SD103C-T, SD103BW-7-F, SD103CW-7-F, BAT48, and DSB0.5A20. Small-signal parts (1N5712-1, 1N6857-1) do not carry this specification due to lower current ratings.

Q: Are there package footprint compatibility issues between DO-35 and SOD-123?

A: Yes. DO-35 is a through-hole axial package with wire leads. SOD-123 is a surface-mount package with gull-wing leads. These packages are not mechanically interchangeable and require different circuit board layouts and assembly processes.

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