BD436 Equivalent & Substitute Parts

Part Overview

The BD436 is a PNP bipolar junction transistor manufactured by STMicroelectronics, rated for 32 V collector-emitter breakdown voltage and 4 A maximum collector current. This device is packaged in SOT-32-3 (TO-225AA, TO-126-3) through-hole configuration and is designed for general-purpose switching and amplification applications requiring 36 W power dissipation capability.

The BD436 is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity and ensure component availability for production, repair, and maintenance applications.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Current - Collector (Ic) (Max)	4	A
Voltage - Collector Emitter Breakdown (Max)	32	V
Power - Max	36	W
DC Current Gain (hFE) (Min)	40	—
Current - Collector Cutoff (Max)	100	µA
Mounting Type	Through Hole	—
Package / Case	TO-225AA, TO-126-3	—
Operating Temperature (Max)	150	°C
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the BD436 is determined by the following critical electrical and mechanical parameters:

Electrical Compatibility Criteria:

Transistor type must be PNP
Maximum collector current (Ic) must be equal to or greater than 4 A
Maximum collector-emitter breakdown voltage (VCEO) must be equal to or greater than 32 V
DC current gain (hFE) minimum must be equal to or greater than 40
Maximum collector cutoff current (ICBO) must be equal to or less than 100 µA
Maximum power dissipation must be equal to or greater than 36 W

Mechanical Compatibility Criteria:

Mounting type must be through-hole
Package must be compatible with TO-225AA or TO-126-3 footprints

The MJE371G meets all substitution criteria. It is an active-status PNP transistor with 4 A collector current, 40 V breakdown voltage (exceeding the 32 V requirement), 40 W power rating, and compatible through-hole TO-126 packaging.

Parameter Comparison

Parameter	BD436 (STMicroelectronics)	MJE371G (onsemi)	Unit
Transistor Type	PNP	PNP	—
Current - Collector (Ic) (Max)	4	4	A
Voltage - Collector Emitter Breakdown (Max)	32	40	V
Current - Collector Cutoff (Max)	100	100	µA
DC Current Gain (hFE) (Min)	40	40	—
Power - Max	36	40	W
Mounting Type	Through Hole	Through Hole	—
Package / Case	TO-225AA, TO-126-3	TO-225AA, TO-126-3	—
Operating Temperature (Max)	150	150	°C
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	—

Engineering Selection Recommendations

The MJE371G is a direct substitute for the BD436 based on the following factors:

Electrical Performance: The MJE371G exceeds the BD436 specifications in collector-emitter breakdown voltage (40 V versus 32 V) and maximum power dissipation (40 W versus 36 W). Both devices share identical maximum collector current (4 A), minimum DC current gain (40), and maximum collector cutoff current (100 µA).

Product Status: The MJE371G is classified as active, ensuring ongoing availability and manufacturing support. The BD436 is obsolete, making the MJE371G the appropriate long-term component selection.

Compliance and Certifications: Both devices are ROHS3 compliant and REACH unaffected, meeting regulatory requirements for electronic component use.

Mechanical Compatibility: Both devices utilize through-hole mounting in TO-126-3 packaging, ensuring direct footprint compatibility on existing printed circuit boards.

Frequently Asked Questions (FAQ)

Q: Can the MJE371G directly replace the BD436 in existing designs?

A: Yes. The MJE371G meets or exceeds all electrical parameters of the BD436 and shares identical through-hole TO-126-3 packaging. Direct substitution is electrically and mechanically compatible.

Q: What is the primary advantage of the MJE371G over the BD436?

A: The MJE371G provides higher collector-emitter breakdown voltage (40 V versus 32 V) and greater power dissipation capability (40 W versus 36 W), offering improved design margin. Additionally, the MJE371G is an active product with ongoing manufacturer support, whereas the BD436 is obsolete.

Q: Are there any electrical parameter differences that affect circuit operation?

A: No. The MJE371G maintains the same maximum collector current (4 A), DC current gain (40 minimum), and collector cutoff current (100 µA maximum) as the BD436. The higher voltage and power ratings of the MJE371G do not negatively impact circuit performance.

Q: Is the TO-126-3 package footprint identical between both devices?

A: Yes. Both the BD436 and MJE371G are packaged in TO-225AA/TO-126-3 through-hole configuration, providing identical pin spacing and mounting hole locations.

Q: Do both devices meet the same regulatory compliance standards?

A: Yes. Both the BD436 and MJE371G are ROHS3 compliant and REACH unaffected, meeting current regulatory requirements for electronic component manufacturing and use.

Q: What is the operating temperature range for each device?

A: The BD436 operates to a maximum junction temperature of 150°C. The MJE371G operates across a temperature range of −65°C to 150°C, providing broader thermal operating capability.

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