S4012R Littelfuse SCR 400V 12A TO-220 Equivalent & Substitute Parts

Part Overview

The S4012R is a silicon-controlled rectifier (SCR) rated for 400V off-state voltage and 12A RMS on-state current in a TO-220 through-hole package. This part is discontinued at DiGi Electronics. Equivalent and substitute parts are necessary to maintain design continuity and ensure component availability for new production runs and field replacements.

Key Parameters

Parameter	Value
Voltage - Off State	400 V
Current - On State (It (RMS)) (Max)	12 A
Voltage - On State (Vtm) (Max)	1.6 V
Voltage - Gate Trigger (Vgt) (Max)	1.5 V
Current - Gate Trigger (Igt) (Max)	20 mA
Current - Hold (Ih) (Max)	40 mA
Operating Temperature Range	-40°C to 125°C
Package / Case	TO-220-3
Mounting Type	Through Hole
SCR Type	Standard Recovery
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution for the S4012R is determined by the following critical parameters:

Voltage Rating: Off-state voltage must be equal to or greater than 400V to maintain circuit protection margins.

Current Rating: On-state RMS current must be equal to or greater than 12A to handle the design load without thermal stress.

Gate Trigger Parameters: Voltage gate trigger (Vgt) and current gate trigger (Igt) must be compatible with the control circuit.

Package Compatibility: TO-220-3 through-hole mounting is required for mechanical and thermal interface compatibility.

Temperature Range: Operating temperature range must encompass -40°C to 125°C.

SCR Type: Standard Recovery classification ensures switching characteristics are compatible with the original design.

The substitute parts are grouped into two categories:

MFR Recommended Substitutes (2N6507G, 2N6507TG): Higher current rating (25A RMS) with identical 400V voltage rating. These parts are pin-compatible, active products from Littelfuse, and provide increased current margin.

Parametric Equivalent (TYN612RG): Higher voltage rating (600V) with matched 12A RMS current rating. This part is from STMicroelectronics and provides enhanced voltage margin while maintaining current compatibility.

Parameter Comparison

Parameter	S4012R (Main)	2N6507G	2N6507TG	TYN612RG
Manufacturer	Littelfuse	Littelfuse Inc.	Littelfuse Inc.	STMicroelectronics
Voltage - Off State	400 V	400 V	400 V	600 V
Current - On State (It (RMS)) (Max)	12 A	25 A	25 A	12 A
Voltage - On State (Vtm) (Max)	1.6 V	1.8 V	1.8 V	1.6 V
Voltage - Gate Trigger (Vgt) (Max)	1.5 V	1.5 V	1.5 V	1.3 V
Current - Gate Trigger (Igt) (Max)	20 mA	30 mA	30 mA	15 mA
Current - Hold (Ih) (Max)	40 mA	40 mA	40 mA	30 mA
Operating Temperature Range	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C	-40°C to 125°C
Package / Case	TO-220-3	TO-220-3	TO-220-3	TO-220-3
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
SCR Type	Standard Recovery	Standard Recovery	Standard Recovery	Standard Recovery
Product Status	Discontinued at DiGi Electronics	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

2N6507G and 2N6507TG: Both parts are active products from Littelfuse with ROHS3 compliance and unlimited moisture sensitivity level. These substitutes provide 25A RMS current capacity against the original 12A specification, offering increased thermal margin and design robustness. Both are electrically and mechanically compatible with the S4012R in TO-220-3 configuration. 2N6507G is available in box packaging with 12,700 units in stock. 2N6507TG is available in box packaging with 2,315 units in stock.

TYN612RG: This STMicroelectronics part is an active product with ROHS3 compliance and unlimited moisture sensitivity level. It maintains the 12A RMS current rating while providing 600V off-state voltage, creating a higher voltage margin for applications where circuit voltage may approach the 400V limit. The part is available in tube packaging with 4,905 units in stock. Gate trigger current is lower (15 mA maximum) compared to the original specification (20 mA maximum).

All substitute parts maintain the TO-220-3 through-hole package, standard recovery SCR type, and -40°C to 125°C operating temperature range required for direct replacement.

Frequently Asked Questions (FAQ)

Q: Can 2N6507G or 2N6507TG be used as direct replacements for S4012R?

A: Yes. Both parts are pin-compatible in TO-220-3 configuration and meet or exceed all critical electrical parameters. The higher 25A RMS current rating provides additional design margin without affecting circuit operation at the original 12A load level.

Q: What is the advantage of using TYN612RG instead of 2N6507G?

A: TYN612RG provides 600V off-state voltage compared to 400V in both the original S4012R and 2N6507G. This higher voltage rating is beneficial in applications where circuit voltage approaches or may transiently exceed 400V. However, TYN612RG maintains the original 12A RMS current rating rather than the increased 25A of the 2N6507 series.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. S4012R, 2N6507G, 2N6507TG, and TYN612RG are all ROHS3 compliant with moisture sensitivity level 1 (unlimited).

Q: What is the difference between 2N6507G and 2N6507TG?

A: Both parts are electrically identical with 400V voltage rating and 25A RMS current rating. The difference is in packaging and inventory availability. 2N6507G is supplied in box packaging with higher stock levels (12,700 units). 2N6507TG is supplied in box packaging with lower stock levels (2,315 units).

Q: Can TYN612RG be used in applications where voltage is limited to 400V?

A: Yes. TYN612RG is rated for 600V off-state voltage and operates correctly in 400V circuits. The higher voltage rating does not create compatibility issues in lower voltage applications.

Q: What are the gate trigger differences between substitutes?

A: S4012R has Vgt maximum of 1.5V and Igt maximum of 20 mA. 2N6507G and 2N6507TG have Vgt maximum of 1.5V and Igt maximum of 30 mA. TYN612RG has Vgt maximum of 1.3V and Igt maximum of 15 mA. These differences must be evaluated against the control circuit design to ensure proper gate drive capability.

Q: Are there thermal considerations when substituting to higher current rated parts?

A: The 2N6507 series (25A RMS) has slightly higher on-state voltage (1.8V maximum) compared to S4012R (1.6V maximum). In applications operating at full 12A load, this results in marginally higher power dissipation. However, the larger die and improved thermal characteristics of the higher-rated part typically result in lower junction temperature under identical load conditions.

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