2N684A Equivalent & Substitute Parts

Part Overview

The 2N684A is a silicon-controlled rectifier (SCR) rated for 150V off-state voltage and 25A RMS on-state current in a TO-48 chassis stud mount package. Manufactured by Central Semiconductor Corp, this component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. 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)	50	mA
Operating Temperature Range	-65 to 125	°C
Package / Case	TO-208AA, TO-48-3, Stud	-
SCR Type	Standard Recovery	-
Mounting Type	Chassis, Stud Mount	-

Substitute Part Grouping Explanation

Substitution of the 2N684A is determined by electrical and mechanical parameter equivalence within the thyristor category. The critical parameters governing substitutability are:

Off-state voltage rating (150V minimum)
RMS on-state current capability (25A minimum)
Gate trigger voltage and current thresholds (Vgt ≤ 2V, Igt ≤ 40mA)
On-state voltage drop (Vtm ≤ 2V)
Hold current specification (Ih ≤ 50mA)
Standard recovery SCR type classification
Chassis stud mount mechanical configuration
TO-48 or equivalent package footprint (TO-208AA)
Operating temperature range (-65°C to 125°C minimum)

The VS-2N684 manufactured by Vishay General Semiconductor meets these electrical and mechanical requirements, providing direct functional equivalence for circuit applications requiring the 2N684A.

Parameter Comparison

Parameter	2N684A (Central Semiconductor)	VS-2N684 (Vishay)	Match Status
Voltage - Off State	150 V	150 V	Equivalent
Current - On State (It (RMS)) (Max)	25 A	25 A	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 - Hold (Ih) (Max)	50 mA	20 mA	VS-2N684 Superior
Operating Temperature Range	-65 to 125 °C	-65 to 125 °C	Equivalent
SCR Type	Standard Recovery	Standard Recovery	Equivalent
Package / Case	TO-208AA, TO-48-3, Stud	TO-208AA, TO-48-3, Stud	Equivalent
Mounting Type	Chassis, Stud Mount	Chassis, Stud Mount	Equivalent
Product Status	Obsolete	Active	VS-2N684 Current
RoHS Status	RoHS Non-Compliant	ROHS3 Compliant	VS-2N684 Compliant

Engineering Selection Recommendations

The VS-2N684 is the manufacturer-recommended substitute for the obsolete 2N684A. Selection of VS-2N684 is based on the following engineering criteria:

All critical electrical parameters match or exceed the 2N684A specification
Identical mechanical package and stud mount configuration ensure direct physical compatibility
Active product status ensures ongoing availability and supply chain continuity
ROHS3 compliance satisfies modern regulatory requirements, whereas the 2N684A is RoHS non-compliant
REACH unaffected status maintained across both parts
Hold current specification of VS-2N684 (20mA) is superior to the 2N684A (50mA), providing improved gate control characteristics

For applications currently using the 2N684A, transition to VS-2N684 eliminates obsolescence risk while maintaining electrical and mechanical compatibility.

Frequently Asked Questions (FAQ)

Q: Can VS-2N684 be used as a direct replacement for 2N684A in existing circuits?

A: Yes. The VS-2N684 meets or exceeds all electrical parameters of the 2N684A, including voltage ratings, current ratings, gate trigger specifications, and operating temperature range. The mechanical package and stud mount configuration are identical, enabling direct substitution without circuit modification.

Q: What is the difference in hold current between the two parts?

A: The 2N684A specifies a maximum hold current (Ih) of 50mA, while the VS-2N684 specifies 20mA. The lower hold current of VS-2N684 represents improved performance, requiring less gate current to maintain SCR conduction once triggered.

Q: Why is RoHS compliance important for this substitution?

A: The 2N684A is RoHS non-compliant, while VS-2N684 is ROHS3 compliant. Modern manufacturing and procurement standards increasingly require RoHS compliance. Selecting VS-2N684 ensures compatibility with current regulatory frameworks and supply chain requirements.

Q: Are the TO-48 and TO-208AA packages interchangeable?

A: Yes. Both the 2N684A and VS-2N684 are available in TO-208AA (TO-48-3) stud mount packages. These designations refer to the same physical package configuration used for chassis-mounted thyristors with stud terminals.

Q: Is the VS-2N684 available in the same packaging format?

A: Yes. The VS-2N684 is supplied in TO-208AA (TO-48) stud mount packaging, matching the mechanical configuration of the 2N684A. Bulk packaging is available from Vishay.

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