MJE182 Equivalent & Substitute Parts

Part Overview

The MJE182 is an NPN bipolar junction transistor manufactured by STMicroelectronics, rated for 80 V collector-emitter breakdown voltage and 3 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 12.5 W power dissipation capability.

The MJE182 is classified as obsolete. Equivalent and substitute parts are necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this transistor specification.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	80	V
Current - Collector (Ic) (Max)	3	A
Vce Saturation (Max) @ Ib, Ic	1.7V @ 600mA, 3A	—
Current - Collector Cutoff (Max)	100	nA
DC Current Gain (hFE) (Min) @ Ic, Vce	50 @ 100mA, 1V	—
Power - Max	12.5	W
Frequency - Transition	50	MHz
Operating Temperature (TJ)	150	°C
Mounting Type	Through Hole	—
Package / Case	TO-225AA, TO-126-3	—
RoHS Status	ROHS3 Compliant	—
REACH Status	REACH Unaffected	—

Substitute Part Grouping Explanation

Substitution of the MJE182 is determined by electrical and mechanical parameter compatibility within the NPN bipolar junction transistor category. The critical parameters governing substitution are:

Primary Substitution Criteria:

Transistor Type: NPN configuration
Voltage - Collector Emitter Breakdown (Max): 80 V or greater
Current - Collector (Ic) (Max): 3 A or greater
Vce Saturation characteristics compatible with application requirements
DC Current Gain (hFE) minimum specifications
Frequency - Transition: 50 MHz or greater for high-speed applications
Mounting Type: Through Hole
Package / Case: TO-225AA or TO-126-3 compatible footprints

Secondary Compatibility Factors:

Power dissipation capability (12.5 W reference)
Operating temperature range
RoHS3 compliance and REACH status
Product status (Active preferred for new designs; Obsolete acceptable for legacy support)

Substitute parts are grouped based on electrical parameter alignment with the MJE182 specification. Parts meeting all primary criteria are classified as direct equivalents. Parts with reduced voltage or current ratings, or modified transistor topology (such as Darlington configuration), are classified as similar alternatives with application-specific limitations.

Parameter Comparison

Parameter	MJE182	MJE182G	2N4923G	BD787G	KSD794AYSTU	MJE181G	MJE270G
Manufacturer	STMicroelectronics	onsemi	onsemi	onsemi	onsemi	onsemi	onsemi
Product Status	Obsolete	Active	Active	Active	Active	Active	Active
Transistor Type	NPN	NPN	NPN	NPN	NPN	NPN	NPN - Darlington
Voltage - Collector Emitter Breakdown (Max)	80 V	80 V	80 V	60 V	60 V	60 V	100 V
Current - Collector (Ic) (Max)	3 A	3 A	1 A	4 A	3 A	3 A	2 A
Vce Saturation (Max) @ Ib, Ic	1.7V @ 600mA, 3A	1.7V @ 600mA, 3A	600mV @ 100mA, 1A	2.5V @ 800mA, 4A	2V @ 150mA, 1.5A	1.7V @ 600mA, 3A	3V @ 1.2mA, 120mA
Current - Collector Cutoff (Max)	100 nA	100 nA	500 µA	100 µA	1 µA	100 nA	1 mA
DC Current Gain (hFE) (Min) @ Ic, Vce	50 @ 100mA, 1V	50 @ 100mA, 1V	30 @ 500mA, 1V	40 @ 200mA, 3V	160 @ 500mA, 5V	50 @ 100mA, 1V	1500 @ 120mA, 10V
Power - Max	12.5 W	1.5 W	30 W	15 W	1 W	1.5 W	1.5 W
Frequency - Transition	50 MHz	50 MHz	3 MHz	50 MHz	60 MHz	50 MHz	6 MHz
Operating Temperature (TJ)	150°C	-65°C ~ 150°C	-65°C ~ 150°C	-65°C ~ 150°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	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	TO-225AA, TO-126-3
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

Direct Equivalent:

MJE182G (onsemi) is the primary direct equivalent to the MJE182. This part maintains identical electrical specifications for voltage breakdown (80 V), collector current (3 A), Vce saturation (1.7V @ 600mA, 3A), DC current gain (50 @ 100mA, 1V), and transition frequency (50 MHz). The MJE182G is manufactured by onsemi and carries Active product status, ensuring ongoing availability and supply chain support. Both parts are ROHS3 compliant and REACH unaffected. The primary difference is reduced maximum power dissipation (1.5 W versus 12.5 W), which is acceptable for applications not requiring the full thermal capability of the original MJE182.

Compatible Alternatives:

MJE181G (onsemi) is compatible for applications where 60 V collector-emitter breakdown voltage is acceptable. This part maintains 3 A collector current, identical Vce saturation characteristics, and 50 MHz transition frequency. MJE181G is Active status with extended operating temperature range (-65°C to 150°C).

BD787G (onsemi) is compatible for applications requiring higher collector current (4 A) but accepting reduced voltage rating (60 V). This part provides 50 MHz transition frequency and 15 W power dissipation.

KSD794AYSTU (onsemi) is compatible for applications accepting reduced voltage (60 V) and power dissipation (1 W) but requiring higher DC current gain (160 @ 500mA, 5V) and transition frequency (60 MHz).

Limited Compatibility:

2N4923G (onsemi) is limited to applications accepting reduced collector current (1 A) and transition frequency (3 MHz), despite offering higher power dissipation (30 W). This part is suitable only for low-current switching applications.

MJE270G (onsemi) employs Darlington transistor topology with significantly different electrical characteristics (1500 hFE, 6 MHz transition frequency, 100 V rating). This part is suitable only for applications specifically designed for Darlington configuration.

All substitute parts maintain through-hole mounting and TO-126-3 package compatibility with the MJE182. All parts are ROHS3 compliant and REACH unaffected, meeting regulatory requirements for new designs and legacy support.

Frequently Asked Questions (FAQ)

Q: Can MJE182G be used as a direct replacement for MJE182?

A: Yes. MJE182G maintains identical electrical specifications for voltage breakdown (80 V), collector current (3 A), Vce saturation, DC current gain, and transition frequency (50 MHz). Both parts use TO-126-3 through-hole packaging. The primary difference is maximum power dissipation (1.5 W versus 12.5 W). Applications not requiring full thermal capability of the original MJE182 can use MJE182G without circuit modification.

Q: What is the difference between MJE182G and MJE181G?

A: MJE182G is rated for 80 V collector-emitter breakdown voltage, while MJE181G is rated for 60 V. Both parts maintain 3 A collector current, identical Vce saturation (1.7V @ 600mA, 3A), and 50 MHz transition frequency. MJE181G is suitable for applications where 60 V voltage rating is sufficient. MJE182G is required for applications demanding 80 V breakdown voltage.

Q: Can 2N4923G replace MJE182?

A: 2N4923G is not a suitable replacement for MJE182 in most applications. While both parts share 80 V voltage rating and TO-126-3 packaging, 2N4923G is limited to 1 A collector current (versus 3 A) and 3 MHz transition frequency (versus 50 MHz). 2N4923G is suitable only for low-current, low-frequency switching applications.

Q: What is the significance of Darlington configuration in MJE270G?

A: MJE270G employs Darlington transistor topology, which combines two transistors internally to achieve very high DC current gain (1500 @ 120mA, 10V versus 50 @ 100mA, 1V for MJE182). Darlington configuration results in higher Vce saturation (3V @ 1.2mA, 120mA) and lower transition frequency (6 MHz). MJE270G is suitable only for applications specifically designed for Darlington characteristics and cannot be used as a direct replacement for standard BJT MJE182.

Q: Are all substitute parts compatible with the MJE182 PCB footprint?

A: Yes. All substitute parts listed use through-hole mounting with TO-225AA or TO-126-3 package designation, maintaining mechanical compatibility with MJE182 PCB layouts. Pin configuration and spacing are identical across all listed parts.

Q: What is the impact of reduced power dissipation in MJE182G?

A: MJE182G is rated for 1.5 W maximum power dissipation, compared to 12.5 W for MJE182. Applications requiring sustained high-power operation or operating in thermally constrained environments may require thermal analysis to confirm MJE182G adequacy. Applications with intermittent or low-duty-cycle operation typically accommodate the reduced power rating without modification.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed (MJE182G, 2N4923G, BD787G, KSD794AYSTU, MJE181G, MJE270G) are ROHS3 compliant and REACH unaffected, meeting regulatory requirements for new product designs and legacy support applications.

Q: Which substitute part offers the best overall compatibility with MJE182?

A: MJE182G offers the best overall compatibility, maintaining identical electrical specifications for voltage breakdown (80 V), collector current (3 A), Vce saturation, DC current gain, and transition frequency (50 MHz). MJE182G is Active status with established supply chain availability through onsemi.

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