BD238 Equivalent & Substitute Parts

Part Overview

The BD238 is a PNP bipolar junction transistor manufactured by STMicroelectronics, rated for 80 V collector-emitter breakdown voltage and 2 A maximum collector current in a Through Hole SOT-32-3 package. The device is classified as Obsolete, necessitating identification of functionally equivalent alternatives for ongoing design requirements and production continuity. Substitute parts must satisfy the electrical specifications and mechanical compatibility requirements of the original component.

Key Parameters

Parameter	BD238 Specification
Transistor Type	PNP
Voltage - Collector Emitter Breakdown (Max)	80 V
Current - Collector (Ic) (Max)	2 A
Power - Max	25 W
Vce Saturation (Max) @ Ib, Ic	600mV @ 100mA, 1A
Current - Collector Cutoff (Max)	100µA (ICBO)
DC Current Gain (hFE) (Min) @ Ic, Vce	25 @ 1A, 2V
Operating Temperature (TJ)	150°C
Mounting Type	Through Hole
Package / Case	TO-225AA, TO-126-3
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the BD238 are evaluated based on the following critical parameters that determine functional equivalence:

Primary Substitution Criteria:

Transistor Type: PNP (mandatory match)
Voltage - Collector Emitter Breakdown: Equal to or greater than 80 V
Current - Collector (Ic) (Max): Equal to or greater than 2 A
Mounting Type: Through Hole (mandatory match)
Package / Case: TO-225AA or TO-126-3 compatible
RoHS Status: ROHS3 Compliant (mandatory match)

Secondary Compatibility Factors:

Vce Saturation characteristics
DC Current Gain (hFE)
Operating Temperature range
Power dissipation capability

Substitutes are grouped by their ability to meet or exceed the BD238 electrical ratings while maintaining mechanical and regulatory compliance. Parts with reduced current or voltage ratings are classified as partial substitutes suitable only for applications with lower electrical demands.

Parameter Comparison

Parameter	BD238	2N4918G	2N4919G	2N4920G	BD180G	MJE253G
Manufacturer	STMicroelectronics	onsemi	onsemi	onsemi	onsemi	onsemi
Transistor Type	PNP	PNP	PNP	PNP	PNP	PNP
Voltage - Collector Emitter Breakdown (Max)	80 V	40 V	60 V	80 V	80 V	100 V
Current - Collector (Ic) (Max)	2 A	1 A	1 A	1 A	1 A	4 A
Vce Saturation (Max) @ Ib, Ic	600mV @ 100mA, 1A	600mV @ 100mA, 1A	600mV @ 100mA, 1A	600mV @ 100mA, 1A	800mV @ 100mA, 1A	600mV @ 100mA, 1A
Current - Collector Cutoff (Max)	100µA (ICBO)	500µA	500µA	500µA	1mA (ICBO)	100nA (ICBO)
DC Current Gain (hFE) (Min) @ Ic, Vce	25 @ 1A, 2V	30 @ 500mA, 1V	30 @ 500mA, 1V	30 @ 500mA, 1V	40 @ 150mA, 2V	40 @ 200mA, 1V
Power - Max	25 W	30 W	30 W	30 W	30 W	1.5 W
Frequency - Transition	Not specified	3MHz	3MHz	3MHz	3MHz	40MHz
Operating Temperature (TJ)	150°C	-65°C ~ 150°C	-65°C ~ 150°C	-65°C ~ 150°C	-65°C ~ 150°C	-65°C ~ 150°C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	TO-225AA, TO-126-3	TO-225AA, TO-126-3	TO-225AA, TO-126-3	TO-225AA, TO-126-3	TO-225AA, TO-126-3	TO-225AA, TO-126-3
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Obsolete	Last Time Buy	Last Time Buy	Active	Active	Active

Engineering Selection Recommendations

Full Electrical Equivalents (80 V, 2 A or greater):

The MJE253G provides the most comprehensive electrical upgrade path. It exceeds BD238 specifications in voltage (100 V), current (4 A), and power dissipation (1.5 W rated, though lower than BD238's 25 W). The MJE253G is Active status with established supply chain availability. This part is suitable for direct replacement in applications requiring the full 2 A collector current at 80 V operation.

The 2N4920G and BD180G both match the 80 V voltage requirement and are rated for 1 A maximum collector current. Both are Active status products with established manufacturing continuity. The 2N4920G is recommended for applications where the 2 A current requirement can be reduced to 1 A without functional impact. The BD180G offers similar voltage and current ratings with higher DC current gain (40 @ 150mA, 2V) compared to 2N4920G (30 @ 500mA, 1V).

Partial Electrical Equivalents (Reduced voltage or current):

The 2N4919G is rated for 60 V maximum collector-emitter breakdown voltage and 1 A maximum collector current. This part is suitable only for applications where the operating voltage does not exceed 60 V and current requirements are 1 A or less. Product status is Last Time Buy.

The 2N4918G is rated for 40 V maximum collector-emitter breakdown voltage and 1 A maximum collector current. This part is suitable only for applications where the operating voltage does not exceed 40 V and current requirements are 1 A or less. Product status is Last Time Buy.

Regulatory and Compliance Status:

All substitute parts maintain ROHS3 compliance and REACH Unaffected status, matching the BD238 regulatory profile. All parts are classified under ECCN EAR99 and HTSUS 8541.29.0095 (or 8541.29.0075 for MJE253G), consistent with export control and tariff classification requirements.

Frequently Asked Questions (FAQ)

Q: Can the 2N4920G directly replace the BD238 in all applications?

A: The 2N4920G matches the 80 V voltage rating and is mechanically compatible through the TO-126-3 package. However, it is rated for 1 A maximum collector current compared to the BD238's 2 A rating. Direct replacement is suitable only for applications where the actual collector current does not exceed 1 A. Applications requiring the full 2 A capability require evaluation of the MJE253G or circuit redesign.

Q: What is the difference between the 2N4918G, 2N4919G, and 2N4920G?

A: These three parts are differentiated by maximum collector-emitter breakdown voltage: 2N4918G (40 V), 2N4919G (60 V), and 2N4920G (80 V). All three are rated for 1 A maximum collector current. Selection depends on the maximum voltage the transistor must withstand in the application. The BD238 operates at 80 V, making the 2N4920G the voltage-equivalent choice among these three options.

Q: Why is the MJE253G rated for only 1.5 W power dissipation when the BD238 is rated for 25 W?

A: Power dissipation rating reflects the thermal design and package characteristics of each device. The MJE253G achieves higher current capability (4 A) and voltage (100 V) through different semiconductor design and thermal management. The 1.5 W rating is the maximum continuous power dissipation under specified thermal conditions. Applications requiring sustained power dissipation above 1.5 W must implement external heat management or select alternative devices.

Q: Are all substitute parts available in the same physical package as the BD238?

A: All substitute parts are available in TO-225AA or TO-126-3 packages, matching the BD238 mechanical compatibility. However, physical pin layout and thermal characteristics may differ. Verification of printed circuit board footprint compatibility is required before implementation.

Q: What is the significance of the Product Status field (Active, Last Time Buy, Obsolete)?

A: Product Status indicates manufacturing continuity and supply availability. Active status indicates ongoing production and established long-term supply. Last Time Buy indicates the manufacturer has announced end-of-life with a final purchase opportunity. Obsolete indicates production has ceased. For new designs, Active status parts (2N4920G, BD180G, MJE253G) are preferred. Last Time Buy parts (2N4918G, 2N4919G) are suitable for existing production with defined end dates.

Q: Can the BD180G be used as a substitute for the BD238?

A: The BD180G matches the 80 V voltage rating and is mechanically compatible. It is rated for 1 A maximum collector current compared to the BD238's 2 A rating. The BD180G exhibits higher DC current gain (40 @ 150mA, 2V) and slightly higher Vce saturation (800mV @ 100mA, 1A). Substitution is suitable for applications where collector current does not exceed 1 A and the higher saturation voltage is acceptable.

Q: What are the key electrical parameters that determine substitution compatibility?

A: The primary parameters are: (1) Transistor Type (PNP), (2) Voltage - Collector Emitter Breakdown (must equal or exceed 80 V for full equivalence), (3) Current - Collector (Ic) (must equal or exceed 2 A for full equivalence), (4) Mounting Type (Through Hole), and (5) Package compatibility (TO-225AA or TO-126-3). Secondary parameters including Vce saturation, DC current gain, and operating temperature range must be evaluated for specific application requirements.

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