NJL4281DG Equivalent & Substitute Parts

Part Overview

The NJL4281DG is an obsolete NPN bipolar junction transistor with integrated isolated diode manufactured by onsemi. This device is rated for 350 V collector-emitter breakdown voltage and 15 A maximum collector current in a Through Hole TO-264 package. The product has reached end-of-life status, necessitating identification of functionally compatible alternatives for ongoing system support and new designs. Substitute parts must maintain electrical and mechanical compatibility within the specified parameter ranges.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN + Diode (Isolated)	—
Current - Collector (Ic) (Max)	15	A
Voltage - Collector Emitter Breakdown (Max)	350	V
Power - Max	230	W
Frequency - Transition	35	MHz
Operating Temperature Range	-65 to 150	°C (TJ)
Mounting Type	Through Hole	—
Package / Case	TO-264-5	—

Substitute Part Grouping Explanation

Substitution of the NJL4281DG is determined by the following critical parameters:

Electrical Compatibility Criteria:

Maximum collector current (Ic): 15 A minimum required
Collector-emitter breakdown voltage (VCEO): Must support 350 V or higher
Power dissipation capability: 230 W or greater
Transition frequency: 35 MHz or higher
DC current gain (hFE): Minimum 80 @ 5A, 5V

Mechanical Compatibility Criteria:

Package type: TO-264-5 (Through Hole)
Pin configuration: 5-pin TO-264 footprint

Environmental Criteria:

Operating temperature range: -65°C to 150°C (TJ)

The NJL3281DG is identified as a substitute part. However, this substitute exhibits reduced electrical performance in specific parameters compared to the main part, requiring evaluation against application requirements.

Parameter Comparison

Parameter	NJL4281DG (Main)	NJL3281DG (Substitute)	Unit
Transistor Type	NPN + Diode (Isolated)	NPN	—
Current - Collector (Ic) (Max)	15	15	A
Voltage - Collector Emitter Breakdown (Max)	350	260	V
Vce Saturation (Max) @ Ib, Ic	1V @ 800mA, 8A	3V @ 1A, 10A	V
Current - Collector Cutoff (Max)	100µA	50µA	A
DC Current Gain (hFE) (Min) @ Ic, Vce	80 @ 5A, 5V	75 @ 5A, 5V	—
Power - Max	230	200	W
Frequency - Transition	35	30	MHz
Operating Temperature Range	-65 to 150	-65 to 150	°C (TJ)
Mounting Type	Through Hole	Through Hole	—
Package / Case	TO-264-5	TO-264-5	—

Engineering Selection Recommendations

NJL4281DG Status: Obsolete. This part is no longer manufactured and existing inventory is limited (849 Pcs). New designs and production systems requiring this component must transition to alternative solutions.

NJL3281DG Status: Active product. This part is currently manufactured and maintained by onsemi with substantial inventory availability (8950 Pcs). The device is RoHS3 compliant and carries REACH Unaffected status.

Substitution Considerations:

The NJL3281DG shares identical mechanical compatibility (TO-264-5 package, Through Hole mounting) and identical maximum collector current (15 A) with the NJL4281DG. Both devices operate across the same temperature range (-65°C to 150°C TJ).

The NJL3281DG exhibits the following electrical differences:

Collector-emitter breakdown voltage is reduced from 350 V to 260 V
Maximum power dissipation is reduced from 230 W to 200 W
Transition frequency is reduced from 35 MHz to 30 MHz
DC current gain is slightly lower (75 vs. 80 @ 5A, 5V)
Vce saturation is higher (3V vs. 1V @ specified conditions)
Integrated diode is not present (NJL3281DG is NPN only, not NPN + Diode)

Selection of the NJL3281DG as a substitute is appropriate only for applications where the reduced voltage rating (260 V), lower power capability (200 W), and absence of integrated diode do not violate circuit requirements. Applications requiring the full 350 V rating, 230 W power dissipation, or integrated diode functionality cannot use this substitute.

Frequently Asked Questions (FAQ)

Q: Can the NJL3281DG directly replace the NJL4281DG in all applications?

A: No. The NJL3281DG has a lower collector-emitter breakdown voltage (260 V vs. 350 V), reduced power rating (200 W vs. 230 W), and lacks the integrated isolated diode present in the NJL4281DG. Substitution is valid only for circuits operating below 260 V and not requiring the integrated diode function.

Q: Are the packages physically identical?

A: Yes. Both the NJL4281DG and NJL3281DG use the TO-264-5 package with Through Hole mounting. Pin-to-pin footprint compatibility is maintained.

Q: What is the primary reason for substitution?

A: The NJL4281DG is obsolete and no longer manufactured. The NJL3281DG is an active product with current manufacturing support and adequate inventory.

Q: Does the NJL3281DG meet RoHS requirements?

A: Yes. The NJL3281DG is RoHS3 compliant. The NJL4281DG does not specify RoHS status.

Q: What is the difference between NPN and NPN + Diode (Isolated)?

A: The NJL4281DG integrates an isolated diode within the same package. The NJL3281DG is a standard NPN transistor without integrated diode. Applications requiring the diode function must provide external components if substituting with the NJL3281DG.

Q: Are the electrical characteristics close enough for high-voltage applications?

A: No. A 90 V difference in breakdown voltage (350 V vs. 260 V) is significant. Applications designed for 350 V operation cannot use the NJL3281DG without circuit redesign.

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

A: Both devices operate from -65°C to 150°C (junction temperature). Temperature range compatibility is maintained between the two parts.

Q: Is the NJL3281DG available in the same packaging format?

A: Yes. The NJL3281DG is supplied in Tube packaging for the TO-264-5 case. The NJL4281DG packaging format is not specified in available data.

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