BD682T Equivalent & Substitute Parts

Part Overview

The BD682T is a PNP Darlington bipolar junction transistor manufactured by onsemi, rated for 100 V collector-emitter breakdown voltage and 4 A maximum collector current in a Through Hole TO-126 package. This component is classified as obsolete, necessitating identification of equivalent substitute parts for ongoing design support and procurement continuity. Substitute parts must maintain electrical and mechanical compatibility within the specified parameter ranges.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP - Darlington	—
Current - Collector (Ic) (Max)	4	A
Voltage - Collector Emitter Breakdown (Max)	100	V
Vce Saturation (Max) @ Ib, Ic	2.5V @ 30mA, 1.5A	—
Current - Collector Cutoff (Max)	500	µA
DC Current Gain (hFE) (Min) @ Ic, Vce	750 @ 1.5A, 3V	—
Mounting Type	Through Hole	—
Package / Case	TO-225AA, TO-126-3	—
Operating Temperature Range	-55°C ~ 150°C	TJ

Substitute Part Grouping Explanation

Substitute parts for the BD682T are determined by equivalence in the following critical parameters:

Transistor Type: PNP - Darlington configuration
Current Rating: Maximum collector current of 4 A
Voltage Rating: Collector-emitter breakdown voltage of 100 V
Saturation Characteristics: Vce saturation of 2.5V @ 30mA, 1.5A
Current Gain: DC current gain (hFE) minimum of 750 @ 1.5A, 3V
Mounting: Through Hole configuration
Package Compatibility: TO-126 or TO-126-3 package variants

The identified substitute parts BD682S and BD682 maintain electrical equivalence across these parameters. Variations in power dissipation rating and RoHS compliance status do not affect functional substitution capability within the specified electrical operating envelope.

Parameter Comparison

Parameter	BD682T (Main)	BD682S (Substitute)	BD682 (Substitute)
Manufacturer	onsemi	onsemi	onsemi
Transistor Type	PNP - Darlington	PNP - Darlington	PNP - Darlington
Current - Collector (Ic) (Max)	4 A	4 A	4 A
Voltage - Collector Emitter Breakdown (Max)	100 V	100 V	100 V
Vce Saturation (Max) @ Ib, Ic	2.5V @ 30mA, 1.5A	2.5V @ 30mA, 1.5A	2.5V @ 30mA, 1.5A
Current - Collector Cutoff (Max)	500 µA	500 µA	500 µA
DC Current Gain (hFE) (Min) @ Ic, Vce	750 @ 1.5A, 3V	750 @ 1.5A, 3V	750 @ 1.5A, 3V
Power - Max	40 W	14 W	40 W
Operating Temperature Range	-55°C ~ 150°C	150°C	-55°C ~ 150°C
Mounting Type	Through Hole	Through Hole	Through Hole
Package / Case	TO-225AA, TO-126-3	TO-225AA, TO-126-3	TO-225AA, TO-126-3
Supplier Device Package	TO-126	TO-126-3	TO-126
Product Status	Obsolete	Obsolete	Obsolete
RoHS Status	RoHS non-compliant	ROHS3 Compliant	RoHS non-compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

BD682 (Base Part Number Equivalent)

The BD682 maintains full electrical equivalence to the BD682T across all critical parameters: 4 A collector current, 100 V breakdown voltage, identical saturation characteristics, and 40 W power rating. Operating temperature range spans -55°C to 150°C. This part is suitable for direct substitution in applications requiring the full temperature operating envelope. RoHS non-compliance status matches the original BD682T specification.

BD682S (RoHS3 Compliant Alternative)

The BD682S provides electrical equivalence with identical current, voltage, and gain specifications. The primary distinction is RoHS3 compliance, making this part suitable for applications subject to RoHS regulatory requirements. The operating temperature maximum is specified at 150°C without a lower limit designation. Power dissipation rating is 14 W, which is lower than the BD682T (40 W). This part is suitable for substitution in applications where power dissipation does not exceed 14 W and RoHS compliance is required.

Selection between BD682 and BD682S depends on regulatory compliance requirements and thermal design constraints. Both parts are electrically equivalent within the specified parameter envelope.

Frequently Asked Questions (FAQ)

Q: Can BD682S replace BD682T in all applications?

A: BD682S provides electrical equivalence in current, voltage, and gain specifications. Selection depends on two factors: (1) RoHS compliance requirement—BD682S is ROHS3 compliant while BD682T is not; (2) thermal design—BD682S has a 14 W power rating versus 40 W for BD682T. If application power dissipation exceeds 14 W, BD682S is not suitable.

Q: What is the difference between TO-126 and TO-126-3 packages?

A: Both are Through Hole packages compatible with the BD682T footprint. The package designation difference reflects supplier device package specification. Mechanical compatibility is maintained across both variants for PCB mounting and thermal management purposes.

Q: Are all three parts (BD682T, BD682S, BD682) electrically interchangeable?

A: BD682T and BD682 are fully electrically interchangeable with identical ratings across all specified parameters. BD682S is electrically equivalent in current, voltage, and gain but has a reduced power rating (14 W versus 40 W). Interchangeability is confirmed for applications within the 14 W power envelope.

Q: What does "Obsolete" product status mean for substitution?

A: Obsolete status indicates the part is no longer in active production. Substitute parts listed maintain the same electrical and mechanical specifications, ensuring functional compatibility in existing designs. All three parts carry obsolete status.

Q: Does RoHS compliance affect electrical performance?

A: RoHS compliance (BD682S) versus non-compliance (BD682T, BD682) does not alter electrical performance. Compliance status reflects manufacturing process and material composition. Selection is based on regulatory requirements applicable to the end application.

Q: Can BD682T operate at temperatures below -55°C?

A: Operating temperature range for BD682T is specified as -55°C to 150°C. Operation outside this range is not specified in the provided parameters.

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