K1400S Equivalent & Substitute Parts Reference

Part Overview

The K1400S is a SIDAC (Silicon Diode for Alternating Current) thyristor manufactured by Littelfuse Inc., rated for 130–146V breakover voltage with 1A peak output current in a DO-214AA/SMB surface mount package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement.

Substiute Parts

K1400S

Littelfuse Inc.In Stock: 900K1400S Datasheet

Current PartRFQ

K1400SRP

Littelfuse Inc.In Stock: 3549K1400SRP Datasheet

DirectRFQ

SMP100LC-90

STMicroelectronicsIn Stock: 1946SMP100LC-90 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the K1400S is determined by the following critical parameters:

• Voltage Rating: Breakover voltage must fall within or closely match the 130–146V specification to ensure proper circuit triggering behavior
• Current Handling: Hold current (Ih) and peak output current must meet or exceed 150 mA and 1 A respectively
• Package Compatibility: Surface mount DO-214AA/SMB package required for direct PCB replacement
• Compliance: RoHS3 compliance maintained across all substitutes

Two substitute options are available:

1. K1400SRP (Littelfuse Inc.) – Direct equivalent with identical electrical specifications, differentiated only by packaging format (Tape & Reel vs. bulk)
2. SMP100LC-90 (STMicroelectronics) – TVS thyristor with different voltage and current ratings; substitution requires circuit-level evaluation

Parameter Comparison

Engineering Selection Recommendations

K1400SRP is the primary substitute for K1400S. Both components are manufactured by Littelfuse Inc. with identical electrical specifications (130–146V breakover, 150 mA hold current, 1 A peak output). The only difference is packaging format: K1400SRP is supplied in Tape & Reel format for automated assembly, while K1400S was supplied in bulk. K1400SRP maintains active product status with 3500 units in stock, ensuring long-term availability. Both components are ROHS3 compliant.

SMP100LC-90 is a TVS thyristor from STMicroelectronics with different electrical characteristics. The breakover voltage is 125V (within the K1400S range), but the off-state voltage is specified at 90V. Peak pulse current capability is significantly higher (400 A at 8/20µs), making this component suitable only for applications requiring enhanced transient suppression. Hold current matches at 150 mA. This substitute requires circuit-level evaluation to confirm compatibility with the original design intent.

Frequently Asked Questions (FAQ)

Q: Can K1400SRP be used as a direct replacement for K1400S?

A: Yes. K1400SRP is electrically identical to K1400S with the same breakover voltage (130–146V), hold current (150 mA), and peak output current (1 A). The only difference is packaging format. Both are ROHS3 compliant and operate across –40°C to 125°C.

Q: What is the difference between K1400S and K1400SRP?

A: K1400S was supplied in bulk packaging; K1400SRP is supplied in Tape & Reel format for automated pick-and-place assembly. Electrical performance is identical.

Q: Is SMP100LC-90 a direct substitute for K1400S?

A: SMP100LC-90 is not a direct substitute. While both are DO-214AA/SMB surface mount thyristors with 150 mA hold current, the SMP100LC-90 has a 125V breakover voltage and is classified as a TVS thyristor with 400 A peak pulse capability. Substitution requires circuit-level analysis to confirm compatibility with the original application.

Q: Are all substitutes ROHS3 compliant?

A: Yes. K1400SRP and SMP100LC-90 are both ROHS3 compliant, matching the compliance status of the original K1400S.

Q: What is the current availability of substitute parts?

A: K1400SRP has 3500 units in stock (active product status). SMP100LC-90 has 1873 units in stock (active product status). K1400S is obsolete with 862 units remaining in stock.

Q: Can these parts be used interchangeably on the same PCB?

A: K1400S and K1400SRP can be used interchangeably due to identical electrical specifications and package compatibility. SMP100LC-90 requires circuit validation before substitution due to different voltage and current ratings.