S8040RTP Equivalent & Substitute Parts

Part Overview

The S8040RTP is a silicon-controlled rectifier (SCR) manufactured by Littelfuse Inc., rated for 800 V off-state voltage with 40 A RMS on-state current capability. This thyristor is designed for standard recovery applications in through-hole TO-220AB-R packaging. The device is currently in active production status with 937 units available in inventory. Alternative models may be required when higher current ratings are needed for specific circuit designs or when supply constraints necessitate component substitution while maintaining electrical compatibility.

Substiute Parts

S8040RTP

Littelfuse Inc.In Stock: 1023S8040RTP Datasheet

Current PartRFQ

S8055RTP

Littelfuse Inc.In Stock: 19394S8055RTP Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

The S8055RTP qualifies as a parametric equivalent to the S8040RTP based on the following critical substitution criteria:

Matching Parameters (Substitution Basis):

• Off-state voltage: 800 V (identical)
• Gate trigger voltage (Vgt): 1.5 V maximum (identical)
• Gate trigger current (Igt): 40 mA maximum (identical)
• On-state voltage (Vtm): 1.8 V maximum (identical)
• Hold current (Ih): 60 mA maximum (identical)
• Off-state leakage current: 20 µA maximum (identical)
• Operating temperature range: -40°C to 125°C (identical)
• Mounting type: Through Hole (identical)
• Package family: TO-220-3 (identical)
• SCR type: Standard Recovery (identical)
• Compliance: ROHS3 Compliant, REACH Unaffected (identical)

Differing Parameters (Higher Rating):

• Current - On State (It RMS) Max: 55 A (versus 40 A in S8040RTP)
• Current - On State (It AV) Max: 35 A (versus 25 A in S8040RTP)
• Non-repetitive surge current: 550 A / 650 A at 50/60 Hz (versus 430 A / 520 A in S8040RTP)

The S8055RTP maintains full electrical and thermal compatibility with the S8040RTP while providing enhanced current-handling capacity. The identical gate-triggering characteristics, on-state voltage drop, and thermal operating range ensure direct functional substitution in circuit applications.

Parameter Comparison

Engineering Selection Recommendations

Both the S8040RTP and S8055RTP are active production components from Littelfuse Inc. with identical ROHS3 compliance and REACH unaffected status, ensuring regulatory compatibility in current and future applications.

The S8040RTP is the primary selection when circuit design specifies a maximum on-state RMS current of 40 A. The S8055RTP serves as a direct substitute when higher current capacity is required, as it maintains all critical electrical parameters (gate triggering, on-state voltage, leakage current, and thermal range) while providing 55 A RMS capability.

Both devices are supplied in TO-220-3 through-hole packaging with identical mounting footprints, enabling direct PCB-level substitution without layout modification. The identical gate-trigger characteristics ensure that existing gate drive circuits require no adjustment.

Selection between these parts depends solely on the application's on-state current requirement. The S8055RTP provides design margin for applications approaching the 40 A limit of the S8040RTP.

Frequently Asked Questions (FAQ)

Q: Can the S8055RTP replace the S8040RTP in existing designs?

A: Yes. The S8055RTP is a direct substitute with identical gate-triggering voltage and current, on-state voltage drop, leakage current, and operating temperature range. The TO-220-3 package footprint is identical, requiring no PCB modification. The higher current rating (55 A RMS versus 40 A RMS) provides additional capacity without affecting circuit operation.

Q: What are the key parameters that determine substitution compatibility?

A: Substitution compatibility is determined by: off-state voltage (800 V), gate trigger voltage maximum (1.5 V), gate trigger current maximum (40 mA), on-state voltage maximum (1.8 V), hold current (60 mA), leakage current (20 µA maximum), operating temperature range (-40°C to 125°C), and package type (TO-220-3). Both parts match on all these parameters.

Q: Are there packaging differences between S8040RTP and S8055RTP?

A: The S8040RTP is supplied in TO-220AB-R packaging (isolated tab), while the S8055RTP uses TO-220 non-isolated tab packaging. Both are TO-220-3 case styles with identical through-hole mounting footprints. Verify tab isolation requirements in your specific application before substitution.

Q: Do gate drive circuits require modification when substituting S8055RTP for S8040RTP?

A: No. Both devices have identical gate trigger voltage (1.5 V maximum) and gate trigger current (40 mA maximum) specifications. Existing gate drive circuits operate without modification.

Q: What is the primary difference between these two SCRs?

A: The S8055RTP provides higher on-state current capacity: 55 A RMS and 35 A average versus 40 A RMS and 25 A average for the S8040RTP. Non-repetitive surge current is also higher (550 A / 650 A at 50/60 Hz versus 430 A / 520 A). All other electrical and thermal characteristics are identical.

Q: Are both parts compliant with current environmental regulations?

A: Yes. Both the S8040RTP and S8055RTP are ROHS3 compliant and REACH unaffected, meeting current regulatory requirements for electronic component manufacturing and use.