1SS400-G Equivalent & Substitute Parts Reference

Part Overview

The 1SS400-G is a general-purpose rectifier diode manufactured by Comchip Technology, designed for surface mount applications in the SOD-523 package. This component operates at 80 V DC reverse voltage with 100 mA average rectified current and features a maximum forward voltage of 1.2 V at 100 mA. The part is Active status and ROHS3 compliant, with unlimited moisture sensitivity level (MSL 1).

Substitute parts are identified when design requirements necessitate alternative sourcing due to inventory constraints, supply chain considerations, or when equivalent electrical and mechanical parameters satisfy circuit specifications.

Key Parameters

Parameter	Value	Unit
Voltage - DC Reverse (Vr) (Max)	80	V
Current - Average Rectified (Io)	100	mA
Voltage - Forward (Vf) (Max) @ If	1.2 V @ 100 mA	V
Reverse Recovery Time (trr)	4	ns
Current - Reverse Leakage @ Vr	100 nA @ 80 V	nA
Capacitance @ Vr, F	3 pF @ 0.5 V, 1 MHz	pF
Package / Case	SC-79, SOD-523	—
Mounting Type	Surface Mount	—
Operating Temperature - Junction (Max)	125	°C
Technology	Standard	—
Speed Classification	Small Signal ≤ 200 mA (Io), Any Speed	—

Substitute Part Grouping Explanation

Substitute parts for the 1SS400-G are classified into two categories based on parametric alignment:

MFR Recommended Substitute: 1N4148WT

The 1N4148WT (Good-Ark Semiconductor) qualifies as a manufacturer-recommended substitute based on matching the following critical parameters: 80 V DC reverse voltage rating, SOD-523 package, surface mount technology, small signal speed classification, and 4 ns reverse recovery time. The 1N4148WT supports 125 mA average rectified current, which exceeds the 100 mA requirement of the 1SS400-G, providing operational margin within the same package and voltage class.

Parametric Equivalent Substitute: 1SS387,L3F

The 1SS387,L3F (Toshiba Semiconductor and Storage) is classified as a parametric equivalent based on identical electrical specifications: 80 V DC reverse voltage, 100 mA average rectified current, 1.2 V forward voltage at 100 mA, 4 ns reverse recovery time, and SOD-523 package footprint. The primary distinction is the supplier device package designation (ESC versus SOD-523), though both maintain SC-79 case compatibility.

Key Parameters Determining Substitution:

Voltage - DC Reverse (Vr) (Max): 80 V
Current - Average Rectified (Io): 100 mA minimum
Package / Case: SOD-523
Mounting Type: Surface Mount
Reverse Recovery Time (trr): 4 ns
Technology: Standard

Parameter Comparison

Parameter	1SS400-G (Comchip)	1N4148WT (Good-Ark)	1SS387,L3F (Toshiba)
Voltage - DC Reverse (Vr) (Max)	80 V	80 V	80 V
Current - Average Rectified (Io)	100 mA	125 mA	100 mA
Voltage - Forward (Vf) (Max) @ If	1.2 V @ 100 mA	1 V @ 50 mA	1.2 V @ 100 mA
Reverse Recovery Time (trr)	4 ns	4 ns	4 ns
Current - Reverse Leakage @ Vr	100 nA @ 80 V	1 µA @ 75 V	500 nA @ 80 V
Capacitance @ Vr, F	3 pF @ 0.5 V, 1 MHz	2 pF @ 0 V, 1 MHz	0.5 pF @ 0 V, 1 MHz
Package / Case	SC-79, SOD-523	SC-79, SOD-523	SC-79, SOD-523
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Operating Temperature - Junction	125°C (Max)	-65°C ~ 150°C	125°C (Max)
Technology	Standard	Standard	Standard
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

1N4148WT Selection Criteria:

The 1N4148WT is suitable for applications where increased current capacity (125 mA versus 100 mA) provides design margin. This part maintains identical voltage rating, package footprint, and switching speed. The extended operating temperature range (-65°C to 150°C) accommodates wider environmental specifications compared to the 1SS400-G maximum of 125°C. All three parts share ROHS3 compliance and MSL 1 rating, ensuring equivalent environmental and regulatory status.

1SS387,L3F Selection Criteria:

The 1SS387,L3F provides parametric equivalence with identical current and voltage specifications. This part is appropriate for direct replacement in applications where the original 1SS400-G specifications are the design baseline. The lower capacitance (0.5 pF versus 3 pF) may provide advantages in high-frequency switching applications. Inventory availability (3200 pcs) should be evaluated against project lead time requirements.

Compliance and Certification Alignment:

All three parts maintain ROHS3 compliance, REACH unaffected status, and MSL 1 rating. EAR99 export classification and identical HTSUS codes (8541.10.0070) confirm regulatory equivalence for procurement and logistics purposes.

Frequently Asked Questions (FAQ)

Q: Can the 1N4148WT directly replace the 1SS400-G in all applications?

A: The 1N4148WT is electrically compatible for circuits designed to the 1SS400-G specifications. The higher current rating (125 mA) and extended temperature range provide operational margin. Both parts use identical SOD-523 packaging and mounting technology. Verify that the application does not depend on the specific forward voltage characteristics at the design operating point, as the 1N4148WT specifies 1 V @ 50 mA versus 1.2 V @ 100 mA for the 1SS400-G.

Q: What is the difference between the 1SS387,L3F and 1SS400-G?

A: The 1SS387,L3F and 1SS400-G share identical electrical parameters: 80 V reverse voltage, 100 mA current, 1.2 V forward voltage at 100 mA, and 4 ns recovery time. The primary difference is manufacturer (Toshiba versus Comchip) and supplier device package designation (ESC versus SOD-523). Both maintain SC-79 case compatibility and surface mount technology.

Q: Are package footprints identical across all three parts?

A: Yes. All three parts use the SOD-523 package with SC-79 case designation. Surface mount footprints are mechanically compatible for PCB assembly without layout modification.

Q: Which substitute part should be selected for high-frequency applications?

A: The 1SS387,L3F exhibits lower capacitance (0.5 pF @ 0 V, 1 MHz) compared to the 1SS400-G (3 pF @ 0.5 V, 1 MHz), which may reduce parasitic effects in high-frequency circuits. The 1N4148WT provides intermediate capacitance (2 pF @ 0 V, 1 MHz). Selection depends on specific frequency requirements and circuit impedance characteristics.

Q: Do all parts meet the same environmental and regulatory standards?

A: Yes. All three parts are ROHS3 compliant, REACH unaffected, and carry MSL 1 (unlimited moisture sensitivity level). EAR99 export classification and HTSUS code 8541.10.0070 are identical across all parts, confirming equivalent regulatory and compliance status.

Q: What is the reverse leakage current difference between the parts?

A: The 1SS400-G specifies 100 nA @ 80 V, the 1SS387,L3F specifies 500 nA @ 80 V, and the 1N4148WT specifies 1 µA @ 75 V. For applications sensitive to leakage current, the 1SS400-G and 1SS387,L3F provide lower leakage characteristics. The 1N4148WT leakage specification is measured at 75 V rather than 80 V, affecting direct comparison.

Q: Can these parts be used interchangeably in production?

A: Interchangeability depends on circuit design specifications. If the design is qualified to the 1SS400-G electrical parameters, both the 1SS387,L3F (parametric equivalent) and 1N4148WT (manufacturer-recommended) are suitable alternatives. Verify that forward voltage characteristics, capacitance, and leakage current specifications do not create functional constraints in the specific application before implementing production substitution.

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