2N684 Equivalent & Substitute Parts

Part Overview

The 2N684 is a silicon controlled rectifier (SCR) rated for 150V off-state voltage and 25A RMS on-state current in a TO-48 chassis mount stud package. Manufactured by Central Semiconductor Corp, this component is classified as obsolete, making equivalent substitutes necessary for new designs and production continuity. The standard recovery SCR type and thermal operating range of -65°C to 125°C define its application scope in industrial switching and power control circuits.

Key Parameters

Parameter	Value	Unit
Voltage - Off State	150	V
Current - On State (It (RMS)) (Max)	25	A
Voltage - Gate Trigger (Vgt) (Max)	2	V
Current - Gate Trigger (Igt) (Max)	40	mA
Voltage - On State (Vtm) (Max)	2	V
Current - Hold (Ih) (Max)	100	mA
Operating Temperature Range	-65 to 125	°C
SCR Type	Standard Recovery	—
Mounting Type	Chassis, Stud Mount	—
Package / Case	TO-208AA, TO-48-3, Stud	—

Substitute Part Grouping Explanation

Substitution of the 2N684 is determined by electrical and mechanical parameter equivalence within the thyristor category. The primary substitution criteria are:

Off-state voltage rating: 150V minimum
RMS on-state current capability: 25A minimum
Gate trigger voltage and current: Vgt ≤ 2V, Igt ≤ 40mA
On-state voltage drop: Vtm ≤ 2V
SCR recovery type: Standard Recovery
Mounting configuration: Chassis, stud mount
Package compatibility: TO-48 or equivalent TO-208AA footprint

The VS-2N684 manufactured by Vishay General Semiconductor meets all these criteria and is designated as the manufacturer-recommended substitute.

Parameter Comparison

Parameter	2N684 (Central Semiconductor)	VS-2N684 (Vishay)	Match Status
Voltage - Off State	150 V	150 V	Equivalent
Voltage - Gate Trigger (Vgt) (Max)	2 V	2 V	Equivalent
Current - Gate Trigger (Igt) (Max)	40 mA	40 mA	Equivalent
Voltage - On State (Vtm) (Max)	2 V	2 V	Equivalent
Current - On State (It (RMS)) (Max)	25 A	25 A	Equivalent
Current - Hold (Ih) (Max)	100 mA	20 mA	Substitute Rated Lower
Current - Off State (Max)	13 mA	6.5 mA	Substitute Rated Lower
Operating Temperature Range	-65 to 125 °C	-65 to 125 °C	Equivalent
SCR Type	Standard Recovery	Standard Recovery	Equivalent
Mounting Type	Chassis, Stud Mount	Chassis, Stud Mount	Equivalent
Package / Case	TO-208AA, TO-48-3, Stud	TO-208AA, TO-48-3, Stud	Equivalent

Engineering Selection Recommendations

The VS-2N684 is the appropriate substitute for the obsolete 2N684. The substitute part maintains electrical equivalence across all critical switching parameters: off-state voltage, gate trigger thresholds, on-state voltage, and RMS current rating. The VS-2N684 is classified as active product status with ROHS3 compliance and EAR99 export classification, providing supply continuity and regulatory alignment for new production.

The VS-2N684 exhibits lower hold current (20mA vs. 100mA) and lower off-state leakage current (6.5mA vs. 13mA), both of which represent improved performance characteristics in standard recovery SCR applications. These differences do not restrict substitution; they indicate enhanced device characteristics suitable for the same circuit topologies.

Frequently Asked Questions (FAQ)

Q: Can the VS-2N684 directly replace the 2N684 in existing designs?

A: Yes. The VS-2N684 meets or exceeds all critical electrical parameters of the 2N684, including voltage ratings, gate trigger specifications, and current ratings. The package footprint is identical (TO-48/TO-208AA stud mount), enabling direct mechanical and electrical substitution.

Q: What is the significance of the lower hold current in the VS-2N684?

A: The VS-2N684 hold current rating of 20mA is lower than the 2N684 specification of 100mA. This represents improved device performance and does not restrict substitution. Lower hold current indicates the device requires less current to maintain conduction, which is beneficial in most switching applications.

Q: Are there compliance differences between the two parts?

A: Yes. The 2N684 is RoHS non-compliant and classified as obsolete. The VS-2N684 is ROHS3 compliant and active product status, making it suitable for applications requiring regulatory compliance and long-term supply assurance.

Q: Does the package designation change affect circuit board layout?

A: No. Both parts use the same TO-48 stud mount package with TO-208AA designation. The mechanical footprint, lead configuration, and mounting requirements are identical, requiring no PCB redesign.

Q: What is the basis for the VS-2N684 substitution recommendation?

A: The VS-2N684 is designated as the manufacturer-recommended substitute by Vishay General Semiconductor. It maintains electrical equivalence across all specified parameters while providing active product status and improved compliance posture.

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