MJE172 Equivalent & Substitute Parts

Part Overview

The MJE172 is a PNP bipolar junction transistor manufactured by STMicroelectronics, rated for 80 V collector-emitter breakdown voltage and 3 A maximum collector current. This component 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 at up to 50 MHz transition frequency.

The MJE172 is classified as obsolete. Equivalent and substitute parts from active manufacturers are available to support continued system design and maintenance requirements. Substitute selection depends on matching electrical parameters including voltage rating, current capacity, gain characteristics, and thermal specifications within the constraints of the application circuit.

Substiute Parts

MJE172

STMicroelectronicsIn Stock: 75114MJE172 Datasheet

Current PartRFQ

MJE172G

onsemiIn Stock: 95500MJE172G Datasheet

DirectRFQ

MJE170G

onsemiIn Stock: 2110MJE170G Datasheet

SimilarRFQ

MJE171G

onsemiIn Stock: 40310MJE171G Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the MJE172 is determined by strict equivalence of the following electrical and mechanical parameters:

Critical Matching Parameters:

• Transistor polarity: PNP
• Collector current rating: 3 A maximum
• Collector-emitter breakdown voltage: 80 V or greater
• Saturation voltage: 1.7 V @ 600mA, 3A
• Collector cutoff current: 100 nA maximum
• DC current gain (hFE): 50 minimum @ 100mA, 1V
• Transition frequency: 50 MHz
• Mounting type: Through Hole
• Package compatibility: TO-225AA or TO-126-3

Substitution Categories:

Direct Equivalent: MJE172G (onsemi) provides identical electrical specifications with matching voltage, current, gain, and frequency ratings. This part is classified as active and represents the primary direct substitute.

Voltage-Derated Substitutes: MJE170G and MJE171G are PNP transistors with identical current, gain, frequency, and saturation characteristics but reduced maximum collector-emitter breakdown voltages (40 V and 60 V respectively). These parts are suitable for applications where the circuit voltage requirement does not exceed their respective ratings.

All substitute parts maintain through-hole mounting compatibility and RoHS3 compliance with the original MJE172.

Parameter Comparison

Engineering Selection Recommendations

MJE172G (onsemi) - Direct Equivalent

The MJE172G is the primary substitute for the obsolete MJE172. This part is manufactured by onsemi and maintains active product status. All electrical parameters match the original specification: 80 V breakdown voltage, 3 A collector current, 50 MHz transition frequency, and 1.7 V saturation voltage. The MJE172G is RoHS3 compliant and suitable for direct replacement in existing circuit designs without modification. This part is recommended for applications requiring the full 80 V voltage rating.

MJE170G (onsemi) - Voltage-Derated Substitute

The MJE170G is a voltage-derated alternative with a 40 V maximum collector-emitter breakdown voltage. All other electrical characteristics remain identical to the MJE172: 3 A current rating, 50 MHz transition frequency, 50 minimum hFE, and 1.7 V saturation voltage. This part is suitable for circuits where the maximum supply voltage does not exceed 40 V. The MJE170G is active and RoHS3 compliant.

MJE171G (onsemi) - Voltage-Derated Substitute

The MJE171G provides a 60 V maximum collector-emitter breakdown voltage with all other specifications matching the original MJE172: 3 A current, 50 MHz transition frequency, 50 minimum hFE, and 1.7 V saturation voltage. This part is suitable for circuits with maximum supply voltages up to 60 V. The MJE171G is active and RoHS3 compliant.

All substitute parts are through-hole mounted in TO-126-3 packaging, compatible with existing PCB layouts designed for the MJE172.

Frequently Asked Questions (FAQ)

Q: Can MJE172G be used as a direct replacement for MJE172?

A: Yes. The MJE172G matches all electrical specifications of the MJE172: 80 V breakdown voltage, 3 A collector current, 50 MHz transition frequency, 50 minimum hFE, and 1.7 V saturation voltage. Both parts use through-hole TO-126-3 packaging. The MJE172G is manufactured by onsemi and maintains active product status.

Q: What is the difference between MJE172G, MJE170G, and MJE171G?

A: The primary difference is the maximum collector-emitter breakdown voltage rating. MJE172G is rated for 80 V, MJE171G for 60 V, and MJE170G for 40 V. All three parts share identical collector current (3 A), saturation voltage (1.7 V @ 600mA, 3A), DC current gain (50 minimum @ 100mA, 1V), and transition frequency (50 MHz) specifications.

Q: Can MJE170G or MJE171G be used in place of MJE172?

A: MJE170G and MJE171G can be used only in applications where the circuit maximum voltage does not exceed their respective breakdown voltage ratings (40 V and 60 V). If the circuit requires operation at voltages above these limits, these parts are not suitable. For circuits operating at 80 V or higher, MJE172G is required.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. The MJE172G, MJE170G, and MJE171G are all RoHS3 compliant, matching the compliance status of the original MJE172.

Q: What is the package compatibility between MJE172 and its substitutes?

A: All substitute parts use through-hole TO-126-3 packaging (TO-225AA case), which is compatible with existing PCB layouts designed for the MJE172. No PCB modifications are required for substitution.

Q: Why is MJE172 classified as obsolete?

A: The MJE172 is no longer manufactured by STMicroelectronics. Active equivalent parts from onsemi (MJE172G, MJE170G, MJE171G) are available to support continued design and maintenance requirements.

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

A: The MJE172G, MJE170G, and MJE171G are rated for operating junction temperatures from −65°C to 150°C, which encompasses the 150°C maximum rating of the original MJE172.