BD442S Equivalent & Substitute Parts

Part Overview

The BD442S is a PNP bipolar junction transistor manufactured by onsemi, rated for 80 V collector-emitter breakdown voltage and 4 A maximum collector current. The device is packaged in TO-126-3 through-hole configuration and delivers 36 W maximum power dissipation with a 3 MHz transition frequency. The BD442S is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity. Active alternatives with identical or comparable electrical characteristics are available from onsemi and other manufacturers.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Collector Current (Max)	4	A
Collector-Emitter Breakdown Voltage (Max)	80	V
Power Dissipation (Max)	36	W
Transition Frequency	3	MHz
Vce Saturation (Max)	800	mV @ 200mA, 2A
DC Current Gain (hFE Min)	40	@ 500mA, 1V
Collector Cutoff Current (Max)	100	µA
Operating Temperature (Max)	150	°C
Mounting Type	Through Hole	—
Package	TO-126-3	—

Substitute Part Grouping Explanation

Substitution of the BD442S is determined by matching critical electrical parameters within the allowed operating range for PNP bipolar transistors. The primary substitution criteria are:

Direct Electrical Equivalents: Parts with identical collector current (4 A), collector-emitter breakdown voltage (80 V), power dissipation (36 W), transition frequency (3 MHz), and saturation voltage characteristics (800 mV @ 200mA, 2A) qualify as direct replacements.

Parametric Equivalents: Parts meeting the same voltage and current ratings but from different manufacturers or with different product status (active vs. obsolete) are classified as parametric equivalents when all critical electrical specifications align.

Similar Parts: Parts with reduced current ratings (1 A to 1.5 A) or lower power dissipation maintain the same voltage class (80 V) and package type (TO-126) but are suitable only for applications with lower current demands.

The following parameters determine substitution eligibility:

Collector current rating (Ic Max)
Collector-emitter breakdown voltage (Vceo Max)
Maximum power dissipation
Saturation voltage characteristics
DC current gain (hFE)
Package and mounting type

Parameter Comparison

Part Number	Manufacturer	Product Status	Ic (Max) [A]	Vceo (Max) [V]	Power (Max) [W]	Vce Sat (Max) [mV]	hFE (Min)	Frequency [MHz]	Package
BD442S	onsemi	Obsolete	4	80	36	800 @ 200mA, 2A	40 @ 500mA, 1V	3	TO-126-3
BD442G	onsemi	Active	4	80	36	800 @ 300mA, 3A	40 @ 500mA, 1V	3	TO-126-3
BD442STU	Fairchild Semiconductor	Active	4	80	36	800 @ 200mA, 2A	40 @ 500mA, 1V	3	TO-126-3
BD442STU-ON	onsemi	Active	4	80	36	800 @ 200mA, 2A	40 @ 500mA, 1V	3	TO-126-3
2N4920G	onsemi	Active	1	80	30	600 @ 100mA, 1A	30 @ 500mA, 1V	3	TO-126-3
BD140G	onsemi	Active	1.5	80	1.25	500 @ 50mA, 500mA	40 @ 150mA, 2V	—	TO-126-3

Engineering Selection Recommendations

Direct Replacement (Preferred): BD442G, BD442STU, and BD442STU-ON are direct electrical equivalents to the BD442S. All three parts maintain identical collector current (4 A), collector-emitter breakdown voltage (80 V), power dissipation (36 W), and transition frequency (3 MHz) specifications. BD442G and BD442STU-ON are manufactured by onsemi, the original manufacturer of the BD442S. BD442STU is manufactured by Fairchild Semiconductor and provides an alternative source. All three parts are in active product status, ensuring long-term availability and supply chain stability.

Compliance Considerations: BD442G, BD442STU, and BD442STU-ON are RoHS3 compliant, whereas the obsolete BD442S does not carry this certification. All substitute parts maintain REACH Unaffected status and EAR99 export classification consistent with the original part.

Reduced Current Applications: The 2N4920G and BD140G are suitable only for applications requiring lower collector current. The 2N4920G supports 1 A maximum collector current with 30 W power dissipation. The BD140G supports 1.5 A maximum collector current but is limited to 1.25 W power dissipation. These parts maintain the 80 V voltage rating and TO-126-3 package but are not suitable for designs requiring the full 4 A current capability of the BD442S.

Frequently Asked Questions (FAQ)

Q: Can BD442G be used as a direct replacement for BD442S?

A: Yes. BD442G is a direct electrical equivalent with identical collector current (4 A), collector-emitter breakdown voltage (80 V), power dissipation (36 W), and saturation voltage characteristics. BD442G is manufactured by onsemi and carries active product status, providing improved supply availability compared to the obsolete BD442S.

Q: What is the difference between BD442STU and BD442STU-ON?

A: BD442STU is manufactured by Fairchild Semiconductor, while BD442STU-ON is manufactured by onsemi. Both parts are parametric equivalents with identical electrical specifications: 4 A collector current, 80 V breakdown voltage, 36 W power dissipation, and 800 mV saturation voltage at 200 mA, 2 A. Selection between these parts depends on manufacturer preference and supply chain availability.

Q: Can 2N4920G replace BD442S in all applications?

A: No. The 2N4920G has a maximum collector current rating of 1 A, compared to 4 A for the BD442S. Applications requiring the full 4 A current capability cannot use the 2N4920G. The 2N4920G is suitable only for designs with reduced current requirements.

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

A: Yes. All substitute parts listed are packaged in TO-126-3 through-hole configuration, matching the BD442S package specification. This ensures mechanical and thermal compatibility with existing PCB layouts and heat sinking arrangements.

Q: What is the operating temperature range for substitute parts?

A: The BD442S specifies a maximum operating temperature of 150°C. BD442G and BD442STU-ON support an operating range of −55°C to 150°C. BD442STU specifies a maximum of 150°C. The 2N4920G supports −65°C to 150°C. All parts meet or exceed the thermal requirements of the original BD442S.

Q: Do substitute parts carry RoHS compliance?

A: BD442G, BD442STU, and BD442STU-ON are RoHS3 compliant. The obsolete BD442S does not carry RoHS certification. If RoHS compliance is required for new designs or procurement, any of the three active substitute parts satisfy this requirement.

Q: What is the moisture sensitivity level (MSL) for substitute parts?

A: BD442G, BD442STU, and BD442STU-ON carry MSL 1 (Unlimited), indicating no moisture sensitivity restrictions. These parts can be stored and handled without special moisture control measures.

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