S4040RTP SCR 400V 40A TO-220 Equivalent & Substitute Parts

Part Overview

The S4040RTP is a Silicon Controlled Rectifier (SCR) manufactured by Littelfuse Inc., rated for 400V off-state voltage and 40A RMS on-state current in a TO-220-3 through-hole package. This thyristor is classified as Standard Recovery type and maintains Active product status with full ROHS3 compliance. Alternative components become necessary when addressing specific application requirements such as higher current ratings, different voltage classes, or alternative manufacturer sourcing while maintaining electrical and mechanical compatibility within the TO-220 package family.

Substiute Parts

S4040RTP

Littelfuse Inc.In Stock: 983S4040RTP Datasheet

Current PartRFQ

S4040RQ2TP

Littelfuse Inc.In Stock: 1938S4040RQ2TP Datasheet

Parametric EquivalentRFQ

S4055RTP

Littelfuse Inc.In Stock: 1394S4055RTP Datasheet

Parametric EquivalentRFQ

TYN408GRG

STMicroelectronicsIn Stock: 1653TYN408GRG Datasheet

MFR RecommendedRFQ

TYN640RG

STMicroelectronicsIn Stock: 2232TYN640RG Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the S4040RTP is determined by three critical parameters: off-state voltage rating, on-state current rating (RMS), and physical package compatibility. All substitute parts must maintain the TO-220-3 through-hole package configuration to ensure mechanical fit and thermal management characteristics.

Substitute parts are grouped into two categories:

Parametric Equivalents maintain identical electrical specifications across voltage and current ratings, differing only in manufacturer or internal design revision. These parts are direct functional replacements.

Manufacturer Recommended Alternatives provide equivalent voltage ratings with variations in current capacity or alternative voltage classes. These parts satisfy specific application needs where current derating or voltage margin enhancement is required.

The following parameters define substitution boundaries:

• Off-state voltage: 400V or higher
• On-state current (RMS): 40A or higher
• Gate trigger voltage: 1.5V or lower
• Package type: TO-220-3 configuration
• SCR type: Standard Recovery
• Operating temperature: -40°C to 125°C minimum

Parameter Comparison

Engineering Selection Recommendations

S4040RQ2TP (Littelfuse Inc.) serves as a direct parametric equivalent with identical electrical specifications. This part maintains 400V off-state voltage and 40A RMS current rating. Selection of this variant is appropriate for applications requiring Littelfuse sourcing continuity or inventory consolidation while preserving all electrical characteristics of the original design.

S4055RTP (Littelfuse Inc.) provides increased on-state current capacity at 55A RMS while maintaining the 400V voltage class. This part is suitable for applications requiring current margin enhancement or thermal derating considerations. The elevated current rating accommodates higher load conditions within the same voltage specification.

TYN408GRG (STMicroelectronics) operates at reduced current capacity of 8A RMS with 400V voltage rating. This part is applicable only in applications where current requirements do not exceed 8A RMS and where STMicroelectronics sourcing is preferred. This represents a current derating scenario and is not suitable for full 40A load conditions.

TYN640RG (STMicroelectronics) provides enhanced voltage rating at 600V off-state while maintaining 40A RMS current capacity. This part is selected for applications requiring higher voltage margin or operation in elevated voltage environments. The 600V rating provides 200V additional voltage headroom compared to the S4040RTP.

All substitute parts maintain Active product status, ROHS3 compliance, and TO-220-3 package configuration, ensuring regulatory alignment and mechanical compatibility with existing PCB designs.

Frequently Asked Questions (FAQ)

Q: Can S4040RQ2TP replace S4040RTP directly in all applications?

A: Yes. S4040RQ2TP is a parametric equivalent with identical voltage (400V), current (40A RMS), gate trigger specifications, and on-state voltage characteristics. Both parts are manufactured by Littelfuse Inc. in TO-220-3 packages and are functionally interchangeable.

Q: When should S4055RTP be selected instead of S4040RTP?

A: S4055RTP is selected when the application requires current capacity exceeding 40A RMS or when thermal derating margins are necessary. The 55A RMS rating provides 15A additional capacity. Both parts share identical 400V voltage rating and gate trigger characteristics, making them compatible within the same voltage class.

Q: Is TYN408GRG suitable as a replacement for S4040RTP?

A: TYN408GRG is not suitable for applications requiring 40A RMS current. This STMicroelectronics part is rated for only 8A RMS and represents a significant current derating. Selection of TYN408GRG is limited to applications with maximum current requirements of 8A RMS at 400V.

Q: What is the primary advantage of TYN640RG over S4040RTP?

A: TYN640RG provides 600V off-state voltage rating compared to S4040RTP's 400V rating. This 200V voltage margin enhancement is beneficial in applications subject to voltage transients or where operation in higher voltage environments is required. Both parts maintain 40A RMS current capacity and TO-220-3 package compatibility.

Q: Are all substitute parts compatible with existing PCB layouts designed for S4040RTP?

A: Yes. All substitute parts utilize TO-220-3 package configuration with identical pin assignments and thermal characteristics. PCB layouts, mounting hardware, and thermal management designs require no modification for any of the listed substitute parts.

Q: Do all substitute parts meet the same compliance standards as S4040RTP?

A: Yes. All substitute parts are ROHS3 compliant, REACH unaffected, and classified as Active products. Regulatory and environmental compliance requirements are satisfied across all listed alternatives.