BD238S Equivalent & Substitute Parts

Part Overview

The BD238S is an obsolete PNP bipolar junction transistor manufactured by onsemi, rated for 80 V collector-emitter breakdown voltage and 2 A maximum collector current. This device is packaged in the TO-126-3 through-hole configuration and delivers 25 W maximum power dissipation with a 3 MHz transition frequency. Due to its obsolete product status, equivalent substitute parts are necessary for ongoing design support and production continuity. The substitute parts listed maintain electrical compatibility within specified parameter ranges while offering active product status and enhanced compliance certifications.

Key Parameters

Parameter	BD238S	Unit
Transistor Type	PNP	—
Voltage - Collector Emitter Breakdown (Max)	80	V
Current - Collector (Ic) (Max)	2	A
Power - Max	25	W
Frequency - Transition	3	MHz
Vce Saturation (Max)	600 mV @ 100 mA, 1 A	—
DC Current Gain (hFE) (Min)	25 @ 1 A, 2 V	—
Operating Temperature (Max)	150	°C
Mounting Type	Through Hole	—
Package / Case	TO-126-3	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution eligibility for the BD238S is determined by the following electrical and mechanical parameters:

Primary Compatibility Criteria:

Transistor Type: PNP (required match)
Voltage - Collector Emitter Breakdown (Max): 80 V (required match)
Mounting Type: Through Hole (required match)
Package / Case: TO-126-3 or TO-126 (compatible package families)

Secondary Compatibility Criteria:

Current - Collector (Ic) (Max): Equal to or greater than 2 A
Power - Max: Equal to or greater than 25 W
Frequency - Transition: Equal to or greater than 3 MHz (where specified)
Operating Temperature Range: Must include 150°C maximum junction temperature

The substitute parts 2N4920G and BD140G satisfy the primary criteria. However, each substitute exhibits different secondary parameter characteristics that affect application suitability.

Parameter Comparison

Parameter	BD238S	2N4920G	BD140G	Unit
Transistor Type	PNP	PNP	PNP	—
Voltage - Collector Emitter Breakdown (Max)	80	80	80	V
Current - Collector (Ic) (Max)	2	1	1.5	A
Power - Max	25	30	1.25	W
Frequency - Transition	3	3	—	MHz
Vce Saturation (Max)	600 mV @ 100 mA, 1 A	600 mV @ 100 mA, 1 A	500 mV @ 50 mA, 500 mA	—
DC Current Gain (hFE) (Min)	25 @ 1 A, 2 V	30 @ 500 mA, 1 V	40 @ 150 mA, 2 V	—
Operating Temperature (Max)	150	150	150	°C
Mounting Type	Through Hole	Through Hole	Through Hole	—
Package / Case	TO-126-3	TO-126	TO-126	—
Product Status	Obsolete	Active	Active	—
RoHS Status	—	ROHS3 Compliant	ROHS3 Compliant	—

Engineering Selection Recommendations

2N4920G Substitution: The 2N4920G is an active product with ROHS3 compliance. It matches the BD238S in voltage rating (80 V), transition frequency (3 MHz), and saturation voltage characteristics. However, the 2N4920G is rated for 1 A maximum collector current, which is 50% lower than the BD238S 2 A rating. The 2N4920G is suitable for applications where collector current does not exceed 1 A. The 30 W power rating exceeds the BD238S specification, providing thermal margin within the reduced current envelope.

BD140G Substitution: The BD140G is an active product with ROHS3 compliance. It matches the BD238S in voltage rating (80 V) and operating temperature range (150°C maximum). The BD140G is rated for 1.5 A maximum collector current, which is 25% lower than the BD238S 2 A rating. The BD140G exhibits superior DC current gain (40 minimum versus 25 minimum) and lower saturation voltage (500 mV versus 600 mV), indicating improved switching characteristics. However, the BD140G power rating is 1.25 W, significantly lower than the BD238S 25 W specification. The BD140G is suitable for low-power switching applications where collector current does not exceed 1.5 A and power dissipation remains below 1.25 W.

Selection Basis: Both substitute parts are active products with current compliance certifications. Selection between 2N4920G and BD140G depends on application current and power requirements. Neither substitute fully replaces the BD238S across its entire rated specification envelope.

Frequently Asked Questions (FAQ)

Q: Can the 2N4920G directly replace the BD238S in all applications?

A: The 2N4920G is electrically compatible for voltage and frequency parameters but is limited to 1 A maximum collector current versus the BD238S 2 A rating. Direct replacement is valid only for applications where collector current does not exceed 1 A.

Q: What is the primary limitation of the BD140G as a substitute?

A: The BD140G maximum power dissipation is 1.25 W, compared to the BD238S 25 W rating. This device is suitable only for low-power applications. Additionally, maximum collector current is 1.5 A, which is 25% below the BD238S specification.

Q: Are the TO-126 and TO-126-3 packages mechanically compatible?

A: Both packages are members of the TO-126 family and share the same three-lead through-hole configuration. Mechanical compatibility is confirmed for PCB mounting and thermal management applications.

Q: Why is the BD238S listed as obsolete?

A: Product status is determined by the manufacturer. Obsolete designation indicates the part is no longer in active production. Substitute parts with active status provide design continuity and supply chain reliability.

Q: Which substitute part offers better compliance certifications?

A: Both 2N4920G and BD140G carry ROHS3 compliance certification. The BD238S compliance status is not specified in the provided data. Both substitutes meet current regulatory requirements for electronic component manufacturing.

Q: Can I use the BD140G in a 25 W power application?

A: No. The BD140G maximum power rating is 1.25 W. Using this device in a 25 W application will result in thermal failure. Application power requirements must not exceed the device specification.

Q: What is the key difference in DC current gain between these parts?

A: The BD238S specifies 25 minimum hFE at 1 A and 2 V. The 2N4920G specifies 30 minimum hFE at 500 mA and 1 V. The BD140G specifies 40 minimum hFE at 150 mA and 2 V. Higher hFE values indicate improved base current efficiency at lower collector currents.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message