MJD340RLG Equivalent & Substitute Parts

Part Overview

The MJD340RLG is an NPN bipolar junction transistor manufactured by onsemi, rated for 300 V collector-emitter breakdown voltage and 500 mA maximum collector current. This surface mount device in DPAK packaging is designed for general-purpose switching and amplification applications requiring moderate voltage and current handling. The part is currently in active production status with RoHS3 compliance and unlimited moisture sensitivity level (MSL 1).

Equivalent and substitute parts are necessary when the primary part becomes unavailable, when alternative manufacturers are required for supply chain diversification, or when application requirements permit operation within the extended electrical parameter ranges of compatible devices.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	300	V
Current - Collector (Ic) (Max)	500	mA
Power - Max	15	W
DC Current Gain (hFE) (Min) @ Ic, Vce	30 @ 50mA, 10V	—
Frequency - Transition	10	MHz
Operating Temperature Range	-65 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	TO-252-3, DPAK (2 Leads + Tab), SC-63	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the MJD340RLG is determined by the following critical electrical and mechanical parameters:

Mandatory Compatibility Criteria:

Transistor Type: NPN (required for circuit polarity)
Package / Case: TO-252-3, DPAK (2 Leads + Tab), SC-63 (required for mechanical fit and thermal interface)
Mounting Type: Surface Mount (required for assembly compatibility)
Voltage - Collector Emitter Breakdown (Max): Must equal or exceed 300 V
Current - Collector (Ic) (Max): Must equal or exceed 500 mA
Power - Max: Must equal or exceed 15 W
DC Current Gain (hFE) (Min): Must equal or exceed 30 at specified test conditions
RoHS Status: ROHS3 Compliant (regulatory requirement)
Moisture Sensitivity Level (MSL): 1 (Unlimited) (handling and storage compatibility)

Substitute parts are grouped into two categories:

Direct Equivalents: Parts with identical electrical specifications (300 V, 500 mA, 15 W, hFE ≥ 30) from different manufacturers or product lines.

Functional Substitutes: Parts with equal or superior electrical ratings that operate within the same application envelope. These include devices with higher voltage ratings, higher current ratings, or higher power dissipation capabilities, which remain compatible when the application does not require the full rated specifications of the substitute device.

Parameter Comparison

Part Number	Manufacturer	Vce (Max) [V]	Ic (Max) [mA]	Power (Max) [W]	hFE (Min) @ Ic, Vce	Frequency - Transition [MHz]	Package	Product Status
MJD340RLG	onsemi	300	500	15	30 @ 50mA, 10V	10	TO-252-3, DPAK	Active
MJD340T4	STMicroelectronics	300	500	15	30 @ 50mA, 10V	—	TO-252-3, DPAK	Active
MJD340-13	Diodes Incorporated	300	500	15	30 @ 50mA, 10V	—	TO-252-3, DPAK	Active
FJD5553TM	onsemi	400	3000	1.25	30 @ 400mA, 3V	—	TO-252-3, DPAK	Active
FJD5555TM	onsemi	400	5000	1.34	20 @ 800mA, 3V	—	TO-252-3, DPAK	Active
KSC5402DTF	onsemi	525	2000	30	6 @ 1A, 1V	11	TO-252-3, DPAK	Last Time Buy
KSC5502DTM	onsemi	600	2000	50	4 @ 1A, 1V	11	TO-252-3, DPAK	Active
BULD741T4	STMicroelectronics	400	2500	30	25 @ 450mA, 3V	—	TO-252-3, DPAK	Active
ZXT1053AKTC	Diodes Incorporated	75	5000	4	300 @ 1A, 2V	140	TO-252-3, DPAK	Active
ZXT690BKTC	Diodes Incorporated	45	3000	3.9	150 @ 2A, 2V	—	TO-252-3, DPAK	Active
ZXT849KTC	Diodes Incorporated	30	7000	4.2	100 @ 1A, 1V	100	TO-252-3, DPAK	Active

Engineering Selection Recommendations

Direct Equivalents (Recommended Primary Substitutes):

MJD340T4 (STMicroelectronics) and MJD340-13 (Diodes Incorporated) are direct electrical and mechanical equivalents to the MJD340RLG. Both devices share identical voltage, current, power, and gain specifications. Both are in active production status with ROHS3 compliance and MSL 1 rating. These parts are suitable for one-to-one replacement without circuit modification.

Functional Substitutes with Superior Ratings:

BULD741T4 (STMicroelectronics) provides higher voltage (400 V) and current (2.5 A) ratings with increased power dissipation (30 W). This device is suitable for applications where the MJD340RLG specifications are met but additional design margin is required. Active production status and full compliance certifications apply.

KSC5402DTF (onsemi) and KSC5502DTM (onsemi) offer significantly higher voltage ratings (525 V and 600 V respectively) and power dissipation (30 W and 50 W). These devices are applicable in high-voltage switching applications. KSC5402DTF carries Last Time Buy status; KSC5502DTM is in active production.

Not Recommended for Direct Substitution:

FJD5553TM and FJD5555TM exhibit reduced power dissipation (1.25 W and 1.34 W respectively) relative to the MJD340RLG (15 W), making them unsuitable for applications requiring the full thermal capability of the primary device.

ZXT1053AKTC, ZXT690BKTC, and ZXT849KTC have voltage ratings below 300 V (75 V, 45 V, and 30 V respectively), disqualifying them from applications requiring the full 300 V breakdown voltage specification of the MJD340RLG.

Frequently Asked Questions (FAQ)

Q: Can MJD340T4 replace MJD340RLG in all applications?

A: Yes. MJD340T4 is a direct electrical equivalent with identical voltage (300 V), current (500 mA), power (15 W), and gain (hFE ≥ 30) specifications. Both devices use the same TO-252-3 DPAK package. No circuit modification is required.

Q: What is the difference between MJD340RLG and MJD340-13?

A: Both are direct equivalents with identical electrical specifications. The primary difference is manufacturer: MJD340RLG is manufactured by onsemi, while MJD340-13 is manufactured by Diodes Incorporated. Both are ROHS3 compliant with MSL 1 rating and active production status.

Q: Can BULD741T4 be used instead of MJD340RLG?

A: BULD741T4 has higher voltage (400 V vs. 300 V) and current (2.5 A vs. 500 mA) ratings with greater power dissipation (30 W vs. 15 W). It is mechanically and electrically compatible in the same package. Use BULD741T4 when the application permits higher ratings or when additional design margin is beneficial. No circuit modification is required for mechanical compatibility.

Q: Why are ZXT849KTC and similar Diodes Incorporated parts not suitable substitutes?

A: ZXT849KTC has a maximum collector-emitter breakdown voltage of 30 V, which is below the MJD340RLG specification of 300 V. This device cannot withstand the voltage levels for which the MJD340RLG is rated and is not suitable for direct substitution.

Q: What does "Last Time Buy" status mean for KSC5402DTF?

A: Last Time Buy status indicates that the manufacturer has announced end-of-life for this part. While currently available, KSC5402DTF will not be produced indefinitely. For new designs or long-term applications, select parts with Active production status such as KSC5502DTM or MJD340T4.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed in this reference are ROHS3 compliant and carry MSL 1 (Unlimited) moisture sensitivity level, matching the compliance profile of the MJD340RLG.

Q: Can FJD5553TM be used in high-power applications?

A: No. FJD5553TM has a maximum power dissipation of 1.25 W, compared to 15 W for the MJD340RLG. This device is unsuitable for applications requiring the thermal capability of the primary part. Use BULD741T4, KSC5402DTF, or KSC5502DTM for high-power requirements.

Q: What is the significance of transition frequency in transistor selection?

A: Transition frequency (fT) indicates the frequency at which current gain drops to unity. MJD340RLG has fT of 10 MHz, suitable for low-frequency switching applications. KSC5402DTF and KSC5502DTM offer 11 MHz, while ZXT1053AKTC provides 140 MHz for higher-frequency applications. For applications operating below 10 MHz, all listed substitutes are compatible.

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