BU941P Equivalent & Substitute Parts Reference

Part Overview

The BU941P by STMicroelectronics is a Bipolar (BJT) NPN Darlington transistor rated for 400 V, 15 A, 155 W, in a TO-247-3 through-hole package. The device has been designated as obsolete, making it necessary to identify alternative models for engineering applications where continued availability and support are required.

Key Parameters

Parameter	Main Part: BU941P
Transistor Type	NPN - Darlington
Current - Collector (Ic) (Max)	15 A
Voltage - Collector Emitter Breakdown (Max)	400 V
Vce Saturation (Max) @ Ib, Ic	2V @ 300mA, 12A
Current - Collector Cutoff (Max)	100µA
DC Current Gain (hFE) (Min) @ Ic, Vce	300 @ 5A, 10V
Power - Max	155 W
Operating Temperature	175°C (TJ)
Mounting Type	Through Hole
Package / Case	TO-247-3
Supplier Device Package	TO-247-3

Substitute Part Grouping Explanation

Substitution is based strictly on the following allowed electrical and mechanical parameters: transistor type, collector current, collector-emitter voltage breakdown, collector cutoff current, DC current gain, saturation voltage at specified test conditions, maximum power dissipation, operating temperature, mounting type, and TO-247-3 packaging. All listed parameters are derived directly from the provided part information.

Parameter Comparison

Parameter	Main Part: BU941P	Substitute: BU931P
Transistor Type	NPN - Darlington	NPN - Darlington
Current - Collector (Ic) (Max)	15 A	15 A
Voltage - Collector Emitter Breakdown (Max)	400 V	400 V
Vce Saturation (Max) @ Ib, Ic	2V @ 300mA, 12A	1.8V @ 250mA, 10A
Current - Collector Cutoff (Max)	100µA	100µA
DC Current Gain (hFE) (Min) @ Ic, Vce	300 @ 5A, 10V	300 @ 5A, 10V
Power - Max	155 W	135 W
Operating Temperature	175°C (TJ)	175°C (TJ)
Mounting Type	Through Hole	Through Hole
Package / Case	TO-247-3	TO-247-3
Supplier Device Package	TO-247-3	TO-247-3

Engineering Selection Recommendations

BU941P is obsolete and no longer available for new designs. BU931P provides active product status and AEC-Q101 automotive qualification, in addition to ROHS3 compliance. Both BU941P and BU931P hold identical compliance features, including unlimited moisture sensitivity level (MSL 1), REACH unaffected status, and EAR99 ECCN classification. BU931P meets the required electrical and mechanical parameters as specified.

Frequently Asked Questions (FAQ)

Q1: What are the critical substitution parameters for BU941P?
A1: Transistor type, collector current, collector-emitter voltage breakdown, collector cutoff current, DC current gain, saturation voltage, maximum power dissipation, operating temperature, mounting method, and package type.

Q2: Does BU931P offer the same TO-247-3 package as BU941P?
A2: Yes, both BU941P and BU931P utilize the TO-247-3 through-hole package.

Q3: Is there any difference in compliance or certification between BU941P and BU931P?
A3: BU931P is AEC-Q101 qualified for automotive applications. Both parts are ROHS3 compliant, have MSL 1, and are unaffected by REACH regulations.

Q4: What is the impact of the difference in maximum power dissipation?
A4: BU931P is rated at 135 W, whereas BU941P is rated at 155 W. For substitution, review application requirements to ensure that 135 W meets system needs.

Q5: Can BU931P replace BU941P without modification to the PCB footprint?
A5: Both parts share the same package and through-hole mounting type, ensuring mechanical compatibility.

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