25TTS08S SCR 800V 25A Equivalent & Substitute Parts

Part Overview

The 25TTS08S is a standard recovery silicon-controlled rectifier (SCR) rated for 800V off-state voltage and 25A RMS on-state current in a surface mount TO-263AB (D2PAK) package. Manufactured by Vishay General Semiconductor - Diodes Division, this part is classified as obsolete. Due to its obsolete status and limited availability from the original manufacturer, equivalent and substitute parts from active manufacturers are necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	Value
Voltage - Off State	800 V
Current - On State (It (RMS)) (Max)	25 A
Voltage - On State (Vtm) (Max)	1.25 V
Voltage - Gate Trigger (Vgt) (Max)	2 V
Current - Gate Trigger (Igt) (Max)	45 mA
Current - Hold (Ih) (Max)	100 mA
Operating Temperature Range	-40°C to 125°C
Package / Case	TO-263-3, D2PAK (2 Leads + Tab), TO-263AB
Mounting Type	Surface Mount
SCR Type	Standard Recovery

Substitute Part Grouping Explanation

Substitution of the 25TTS08S is determined by the following critical parameters:

Voltage Rating (Off-State): Must be 800V minimum to maintain electrical safety margins
Current Rating (RMS): Must support 25A RMS on-state current or higher
Package Compatibility: Must use TO-263-3 D2PAK footprint for direct PCB compatibility
Gate Trigger Characteristics: Vgt and Igt must be within acceptable operating ranges for existing gate drive circuits
On-State Voltage (Vtm): Lower values indicate better thermal performance; values up to 1.8V are acceptable for this application class
Temperature Range: Must maintain -40°C to 125°C operating specification
Product Status: Active status ensures ongoing availability and supply chain reliability

Substitute parts are grouped into two categories: direct replacements (matching 25A RMS rating) and higher-current alternatives (40A and 55A RMS ratings) that provide design margin and thermal headroom while maintaining full backward compatibility.

Parameter Comparison

Part Number	Manufacturer	Voff (V)	It(RMS) (A)	Vtm (V)	Vgt (V)	Igt (mA)	Ih (mA)	Package	Status	RoHS
25TTS08S	Vishay	800	25	1.25	2	45	100	TO-263AB	Obsolete	Non-compliant
S8025NRP	Littelfuse	800	25	1.6	1.5	35	50	TO-263	Active	ROHS3
S8025NTP	Littelfuse	800	25	1.6	1.5	35	50	TO-263	Active	ROHS3
TN2540-800G-TR	STMicroelectronics	800	25	1.6	1.3	40	50	D2PAK	Active	ROHS3
CS19-08HO1S-TRL	IXYS	800	29	1.6	1.5	28	50	TO-263AA	Active	ROHS3
S8040NRP	Littelfuse	800	40	1.8	1.5	40	60	TO-263	Active	ROHS3
S8040NTP	Littelfuse	800	40	1.8	1.5	40	60	TO-263	Active	ROHS3
S8055NRP	Littelfuse	800	55	1.8	1.5	40	60	TO-263	Active	ROHS3
S8055NTP	Littelfuse	800	55	1.8	1.5	40	60	TO-263	Active	ROHS3

Engineering Selection Recommendations

Direct Replacement (25A RMS Rating)

S8025NRP and S8025NTP from Littelfuse, and TN2540-800G-TR from STMicroelectronics provide electrical equivalence to the 25TTS08S with identical 25A RMS current ratings and 800V voltage specifications. All three are active products with ROHS3 compliance. S8025NRP is supplied in cut tape format, S8025NTP in tube packaging, and TN2540-800G-TR in cut tape with Digi-Reel. These parts maintain the same thermal and electrical operating envelope as the original part.

Higher Current Alternatives (40A and 55A RMS Ratings)

S8040NRP, S8040NTP, S8055NRP, and S8055NTP from Littelfuse provide increased current capacity while maintaining 800V voltage rating and TO-263 D2PAK package compatibility. These parts are suitable for applications requiring design margin or thermal headroom beyond the original 25A specification. All are active products with ROHS3 compliance.

IXYS Alternative

CS19-08HO1S-TRL from IXYS offers 29A RMS capacity in TO-263AA package with active product status and ROHS3 compliance. This part provides a modest current increase over the 25A baseline while maintaining full electrical compatibility.

All substitute parts listed maintain the -40°C to 125°C operating temperature range and standard recovery SCR type of the original part. Product status and RoHS compliance ensure long-term supply chain viability for new designs.

Frequently Asked Questions (FAQ)

Q: Can S8040NRP or S8055NRP be used as direct replacements for 25TTS08S?

A: Yes. These parts share identical 800V voltage rating, TO-263 D2PAK package footprint, and -40°C to 125°C temperature range. The higher current ratings (40A and 55A RMS) are backward compatible with 25A applications, providing additional thermal margin. Gate trigger characteristics (Vgt 1.5V, Igt 40mA) are within acceptable ranges for existing gate drive circuits designed for the original part.

Q: What is the difference between S8025NRP and S8025NTP?

A: Both parts are electrically identical Littelfuse SCR 800V 25A devices. The difference is packaging: S8025NRP is supplied in cut tape (CT) format, while S8025NTP is supplied in tube packaging. Selection depends on assembly process requirements and inventory management preferences.

Q: Is TN2540-800G-TR compatible with the original 25TTS08S footprint?

A: Yes. TN2540-800G-TR uses D2PAK package, which is electrically and mechanically compatible with the TO-263AB package of the 25TTS08S. Both packages have identical lead configuration and thermal tab placement for PCB mounting.

Q: Why do substitute parts show lower gate trigger voltage (Vgt) values?

A: Substitute parts from Littelfuse, STMicroelectronics, and IXYS specify Vgt maximum values of 1.3V to 1.5V, compared to 2V for the original 25TTS08S. Lower gate trigger voltage indicates improved gate sensitivity and is not a compatibility issue. Existing gate drive circuits designed for 2V triggering will operate reliably with these lower-threshold parts.

Q: Are all substitute parts RoHS compliant?

A: Yes. All active substitute parts listed carry ROHS3 compliance certification. The original 25TTS08S is marked as RoHS non-compliant due to its obsolete status. Substitution with ROHS3-compliant parts is necessary for new designs subject to RoHS regulations.

Q: Can I use CS19-08HO1S-TRL as a substitute if my application requires exactly 25A?

A: Yes. CS19-08HO1S-TRL is rated for 29A RMS, which exceeds the 25A requirement. The part maintains 800V voltage rating, TO-263AA package compatibility, and -40°C to 125°C temperature range. The additional 4A capacity provides design margin without affecting circuit operation.

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