MJD31C Equivalent & Substitute Parts

Part Overview

The MJD31C is an NPN bipolar junction transistor manufactured by STMicroelectronics, rated for 100 V collector-emitter breakdown voltage and 3 A maximum collector current in a surface mount DPAK package. This device is classified as obsolete, which necessitates identification of equivalent and substitute components for ongoing production and maintenance applications. The MJD31C remains available in inventory (82,900 pieces), but active alternatives with identical or compatible electrical characteristics are required for new designs and long-term supply chain continuity.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Collector Current (Max)	3	A
Collector-Emitter Breakdown Voltage (Max)	100	V
Vce Saturation (Max)	1.2	V @ 375mA, 3A
Collector Cutoff Current (Max)	50	µA
DC Current Gain (hFE Min)	10	@ 3A, 4V
Power Dissipation (Max)	15	W
Operating Temperature (Max)	150	°C (TJ)
Package Type	TO-252-3 (DPAK)	—
Mounting Type	Surface Mount	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitution of the MJD31C is determined by strict equivalence across the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

Transistor type: NPN
Collector current rating: 3 A (minimum)
Collector-emitter breakdown voltage: 100 V (minimum)
Vce saturation: 1.2 V @ 375mA, 3A
Collector cutoff current: 50 µA (maximum)
DC current gain (hFE): 10 @ 3A, 4V (minimum)
Package: TO-252-3 (DPAK) surface mount
Mounting type: Surface mount

Direct Equivalents are parts manufactured by different suppliers or in different packaging formats (Tape & Reel, Cut Tape, Tube) that maintain identical electrical specifications and the same base product number (MJD31).

Similar Alternatives are parts with the same voltage and current ratings but different manufacturers, base product numbers, or secondary electrical characteristics (such as transition frequency or power dissipation). These parts satisfy the core electrical requirements but may differ in frequency response or thermal performance.

Parameter Comparison

Part Number	Manufacturer	Product Status	Ic (Max) A	Vce(br) V	Vce Sat V	hFE Min	Power W	Freq MHz	Temp °C	Package	RoHS
MJD31C	STMicroelectronics	Obsolete	3	100	1.2 @ 375mA, 3A	10 @ 3A, 4V	15	—	150	TO-252-3 (DPAK)	ROHS3
MJD31CT4-A	STMicroelectronics	Active	3	100	1.2 @ 375mA, 3A	10 @ 3A, 4V	15	—	150	TO-252-3 (DPAK)	ROHS3
MJD31CT4	onsemi	Obsolete	3	100	1.2 @ 375mA, 3A	10 @ 3A, 4V	15	3	150	TO-252-3 (DPAK)	Non-compliant
MJD31C-13	Diodes Incorporated	Active	3	100	1.2 @ 375mA, 3A	10 @ 3A, 4V	1.56	3	150	TO-252-3 (DPAK)	ROHS3
MJD31CG	onsemi	Active	3	100	1.2 @ 375mA, 3A	10 @ 3A, 4V	1.56	3	150	TO-252-3 (DPAK)	ROHS3
MJD31CQ-13	Diodes Incorporated	Not For New Designs	3	100	1.2 @ 375mA, 3A	10 @ 3A, 4V	15	3	150	TO-252-3 (DPAK)	ROHS3
NJVMJD31CG	onsemi	Active	3	100	1.2 @ 375mA, 3A	10 @ 3A, 4V	1.56	3	150	TO-252-3 (DPAK)	ROHS3
MJD243G	onsemi	Active	4	100	600mV @ 100mA, 1A	40 @ 200mA, 1V	1.4	40	150	TO-252-3 (DPAK)	ROHS3

Engineering Selection Recommendations

Recommended Primary Substitutes (Direct Equivalents):

MJD31CT4-A (STMicroelectronics, Active) — Identical electrical specifications to MJD31C with active product status. ROHS3 compliant. Available in Cut Tape and Digi-Reel packaging. This is the preferred direct replacement for new designs and production continuity.
MJD31C-13 (Diodes Incorporated, Active) — Maintains all core electrical parameters (3 A, 100 V, 1.2 V saturation, 10 hFE minimum). ROHS3 compliant. Active product status ensures long-term availability. Power dissipation specification differs (1.56 W vs. 15 W), which reflects thermal measurement methodology rather than functional limitation in typical applications.
MJD31CG (onsemi, Active) — Functionally equivalent with active status and ROHS3 compliance. Supplied in Tube packaging. Power dissipation specification (1.56 W) is consistent with Diodes Incorporated variant.
NJVMJD31CG (onsemi, Active) — Equivalent electrical performance with active product status and ROHS3 compliance. Supplied in Tube packaging. Extended operating temperature range (-65°C to 150°C) provides additional thermal margin.

Secondary Alternatives (Similar Characteristics):

MJD243G (onsemi, Active) — Higher collector current rating (4 A vs. 3 A) with 100 V breakdown voltage. Suitable for applications requiring increased current capacity. Different saturation voltage (600 mV) and current gain characteristics. ROHS3 compliant and active status.

Parts Not Recommended for New Designs:

MJD31CT4 (onsemi, Obsolete) — RoHS non-compliant. Obsolete status limits supply chain viability.
MJD31CQ-13 (Diodes Incorporated, Not For New Designs) — Explicitly marked as not suitable for new design implementations.

Frequently Asked Questions (FAQ)

Q: Can MJD31CT4-A directly replace MJD31C without circuit modification?

A: Yes. MJD31CT4-A maintains identical electrical specifications across all critical parameters: 3 A collector current, 100 V breakdown voltage, 1.2 V saturation voltage, and 10 minimum hFE. The only difference is packaging format (Cut Tape/Digi-Reel vs. Tape & Reel), which does not affect electrical performance. Both use TO-252-3 (DPAK) surface mount package.

Q: What is the difference between MJD31C-13 and MJD31CG if they have the same electrical ratings?

A: Both parts meet the core electrical requirements (3 A, 100 V, 1.2 V saturation). The primary differences are manufacturer (Diodes Incorporated vs. onsemi), packaging format (Tape & Reel vs. Tube), and power dissipation specification (1.56 W vs. 15 W). The power specification difference reflects measurement methodology and does not indicate functional limitation. Both are ROHS3 compliant and active.

Q: Why does MJD31C-13 specify 1.56 W power dissipation while MJD31C specifies 15 W?

A: Power dissipation specifications reflect different measurement conditions and thermal test methodologies established by each manufacturer. Both parts are rated for the same 3 A collector current and 100 V breakdown voltage. The lower specification does not indicate reduced capability; it reflects the specific thermal environment used during characterization. Circuit design should be based on actual application thermal requirements rather than datasheet power ratings alone.

Q: Is MJD243G a suitable substitute for MJD31C?

A: MJD243G is a similar alternative with the same 100 V breakdown voltage but higher collector current rating (4 A vs. 3 A). It can be used in applications where the MJD31C is specified, as it provides additional current capacity. However, saturation voltage (600 mV) and current gain characteristics differ from MJD31C (1.2 V saturation, 10 hFE minimum). Verify that these differences do not affect circuit performance before substitution.

Q: Should I use MJD31CT4 (onsemi) as a substitute?

A: MJD31CT4 is not recommended for new designs. Although it maintains the required electrical specifications, it is marked as obsolete and is RoHS non-compliant. Use MJD31CT4-A (STMicroelectronics) or MJD31CG (onsemi) instead, both of which are active and ROHS3 compliant.

Q: What is the difference between Tape & Reel, Cut Tape, and Tube packaging?

A: These are packaging and delivery formats that do not affect electrical performance. Tape & Reel (TR) and Cut Tape (CT) are used for automated assembly lines. Tube packaging is used for manual assembly or lower-volume applications. All three formats contain the same TO-252-3 (DPAK) surface mount component. Select based on your assembly process requirements.

Q: Are all recommended substitutes ROHS3 compliant?

A: All recommended primary substitutes (MJD31CT4-A, MJD31C-13, MJD31CG, NJVMJD31CG) are ROHS3 compliant. MJD31CT4 (onsemi) is RoHS non-compliant and should not be used. MJD243G is ROHS3 compliant.

Q: Can I use NJVMJD31CG instead of MJD31CG?

A: Yes. NJVMJD31CG is functionally equivalent to MJD31CG with identical electrical specifications and ROHS3 compliance. The primary difference is the extended operating temperature range (-65°C to 150°C vs. -65°C to 150°C for MJD31CG). Both are active products supplied in Tube packaging. Selection depends on your specific temperature requirements and supplier availability.

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