BUL49DFP Equivalent & Substitute Parts

Part Overview

The BUL49DFP is an NPN bipolar junction transistor manufactured by STMicroelectronics, rated for 450 V collector-emitter breakdown voltage and 5 A maximum collector current in a TO-220FP through-hole package. This device is classified as obsolete, necessitating identification of equivalent substitute components for ongoing design support and procurement continuity. Substitute parts must maintain electrical and mechanical compatibility within the specified parameter ranges.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	450	V
Current - Collector (Ic) (Max)	5	A
Power - Max	34	W
Mounting Type	Through Hole	—
Package / Case	TO-220-3 Full Pack	—
Operating Temperature (Max)	150	°C (TJ)
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitute parts for the BUL49DFP are identified based on the following electrical and mechanical criteria:

Primary Matching Criteria:

Transistor type: NPN configuration
Voltage rating: Collector-emitter breakdown voltage ≥ 450 V
Current rating: Maximum collector current ≥ 5 A
Package type: TO-220-3 through-hole mounting
Compliance: ROHS3 compliant

Secondary Compatibility Factors:

Power dissipation capability
Operating temperature range
Product status and availability

Two substitute parts meet these criteria with varying degrees of parameter alignment. The MJF18004G provides the closest electrical match with identical voltage and current ratings. The FJPF3305H1TU offers reduced ratings and is suitable only for applications with lower voltage or current requirements.

Parameter Comparison

Parameter	BUL49DFP (Main)	MJF18004G (Substitute)	FJPF3305H1TU (Substitute)
Manufacturer	STMicroelectronics	onsemi	onsemi
Transistor Type	NPN	NPN	NPN
Voltage - Collector Emitter Breakdown (Max)	450 V	450 V	400 V
Current - Collector (Ic) (Max)	5 A	5 A	4 A
Power - Max	34 W	35 W	30 W
Vce Saturation (Max)	1.2 V @ 800mA, 4A	750 mV @ 500mA, 2.5A	1 V @ 1A, 4A
Current - Collector Cutoff (Max)	100 µA	100 µA	1 µA (ICBO)
DC Current Gain (hFE) (Min)	4 @ 7A, 10V	14 @ 300mA, 5V	19 @ 1A, 5V
Frequency - Transition	—	13 MHz	4 MHz
Operating Temperature (Max)	150°C (TJ)	150°C (TJ)	150°C (TJ)
Mounting Type	Through Hole	Through Hole	Through Hole
Package / Case	TO-220-3 Full Pack	TO-220-3 Full Pack	TO-220-3 Full Pack
Product Status	Obsolete	Active	Obsolete
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

MJF18004G (Primary Substitute): The MJF18004G is the preferred substitute for the BUL49DFP. This part maintains identical voltage (450 V) and current (5 A) ratings, equivalent power dissipation (35 W vs. 34 W), and matching TO-220FP packaging. The MJF18004G is currently in active product status with 2100 units in stock, ensuring long-term availability. Both devices are ROHS3 compliant and carry identical ECCN and HTSUS classifications. The MJF18004G includes a higher transition frequency (13 MHz) and improved saturation voltage characteristics, providing enhanced performance in switching applications.

FJPF3305H1TU (Secondary Substitute): The FJPF3305H1TU is a reduced-rating substitute suitable only for applications where voltage and current requirements do not exceed 400 V and 4 A respectively. This part is also obsolete and should not be selected for new designs requiring the full 450 V / 5 A capability of the BUL49DFP. The FJPF3305H1TU is acceptable only as a substitute in legacy systems with lower electrical demands.

Frequently Asked Questions (FAQ)

Q: Can the MJF18004G directly replace the BUL49DFP in all applications?

A: The MJF18004G is electrically and mechanically compatible with the BUL49DFP for applications requiring 450 V / 5 A operation. Both devices share identical voltage and current ratings, matching TO-220-3 package geometry, and equivalent thermal characteristics. The MJF18004G's improved saturation voltage and higher transition frequency provide performance benefits in switching circuits.

Q: What are the limitations of the FJPF3305H1TU as a substitute?

A: The FJPF3305H1TU has reduced electrical ratings: 400 V maximum breakdown voltage (50 V lower) and 4 A maximum collector current (1 A lower). This part is suitable only for applications with lower voltage or current demands. It cannot be used as a direct replacement in circuits designed for the full 450 V / 5 A capability.

Q: Are all substitute parts available in the same package?

A: Yes. Both the MJF18004G and FJPF3305H1TU are supplied in TO-220-3 through-hole packages, matching the BUL49DFP package configuration. Pin assignments and mechanical dimensions are compatible with existing PCB layouts.

Q: What is the product status significance for these substitutes?

A: The MJF18004G is in active production status, ensuring continued availability and long-term supply chain stability. The FJPF3305H1TU is obsolete, similar to the BUL49DFP, and should not be selected for new designs. For obsolete system maintenance, the MJF18004G is the recommended choice due to its active status.

Q: Do all parts meet the same compliance requirements?

A: Yes. The BUL49DFP, MJF18004G, and FJPF3305H1TU are all ROHS3 compliant, REACH unaffected, and classified under ECCN EAR99 and HTSUS 8541.29.0095. All parts meet identical regulatory and environmental standards.

Q: How do the DC current gain specifications differ between parts?

A: The BUL49DFP specifies a minimum hFE of 4 at 7 A and 10 V. The MJF18004G specifies 14 at 300 mA and 5 V, while the FJPF3305H1TU specifies 19 at 1 A and 5 V. These measurements are taken at different operating points and cannot be directly compared. Actual gain performance depends on the specific bias conditions in the application circuit.

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