BC33740BU Equivalent & Substitute Parts

Part Overview

The BC33740BU is an NPN bipolar junction transistor manufactured by onsemi, designed for general-purpose switching and amplification applications. This through-hole component operates at a maximum collector current of 800 mA with a collector-emitter breakdown voltage of 45 V and maximum power dissipation of 625 mW. The device is currently in active production status with 5861 units in stock. Substitute parts are identified when equivalent electrical performance and mechanical compatibility are required due to supply constraints, procurement preferences, or design flexibility needs.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Current - Collector (Ic) (Max)	800	mA
Voltage - Collector Emitter Breakdown (Max)	45	V
Vce Saturation (Max) @ Ib, Ic	700mV @ 50mA, 500mA	V
Current - Collector Cutoff (Max)	100	nA
DC Current Gain (hFE) (Min) @ Ic, Vce	250 @ 100mA, 1V	—
Power - Max	625	mW
Frequency - Transition	100	MHz
Operating Temperature (TJ)	150	°C
Mounting Type	Through Hole	—
Package / Case	TO-226-3, TO-92-3 (TO-226AA)	—

Substitute Part Grouping Explanation

Substitution of the BC33740BU is determined by strict equivalence across the following critical parameters:

Transistor Type: NPN configuration required
Maximum Collector Current (Ic): 800 mA minimum
Collector-Emitter Breakdown Voltage (VCEO): 45 V minimum
Saturation Voltage (Vce Sat): 700mV @ 50mA, 500mA maximum
DC Current Gain (hFE): 250 minimum @ 100mA, 1V
Maximum Power Dissipation: 625 mW minimum
Transition Frequency: 100 MHz minimum
Package Type: TO-92-3 (TO-226-3) through-hole configuration
Mounting Type: Through Hole

The BC337-40BK manufactured by Diotec Semiconductor meets all specified electrical parameters and maintains mechanical compatibility through identical package designation. Both devices are classified as active products with RoHS compliance status documented.

Parameter Comparison

Parameter	BC33740BU (onsemi)	BC337-40BK (Diotec)	Match Status
Transistor Type	NPN	NPN	Equivalent
Current - Collector (Ic) (Max)	800 mA	800 mA	Equivalent
Voltage - Collector Emitter Breakdown (Max)	45 V	45 V	Equivalent
Vce Saturation (Max) @ Ib, Ic	700mV @ 50mA, 500mA	700mV @ 50mA, 500mA	Equivalent
Current - Collector Cutoff (Max)	100 nA	100 nA	Equivalent
DC Current Gain (hFE) (Min) @ Ic, Vce	250 @ 100mA, 1V	250 @ 100mA, 1V	Equivalent
Power - Max	625 mW	625 mW	Equivalent
Frequency - Transition	100 MHz	100 MHz	Equivalent
Operating Temperature (TJ)	150°C	−55°C ~ 150°C	Compatible
Mounting Type	Through Hole	Through Hole	Equivalent
Package / Case	TO-226-3, TO-92-3	TO-226-3, TO-92-3	Equivalent

Engineering Selection Recommendations

BC33740BU (onsemi): Select this part when onsemi supply chain preference is established or when RoHS3 compliance certification is specifically required. Product status is active with 5861 units currently in inventory. REACH status is listed as REACH Unaffected.

BC337-40BK (Diotec Semiconductor): Select this part as a direct substitute when supply availability from onsemi is constrained or when Diotec procurement channels are preferred. This device provides identical electrical performance across all critical parameters. Operating temperature range extends to −55°C, providing broader environmental capability. Product status is active with 5500 units in inventory. RoHS compliance status is not applicable per manufacturer documentation.

Both devices are suitable for direct substitution in through-hole PCB applications requiring NPN transistor functionality within the specified electrical envelope. No circuit redesign is required when transitioning between these parts.

Frequently Asked Questions (FAQ)

Q: Can BC337-40BK replace BC33740BU in existing designs?

A: Yes. Both devices are electrically equivalent across all critical parameters including collector current, breakdown voltage, saturation voltage, current gain, power dissipation, and transition frequency. Package designation is identical (TO-92-3), enabling direct mechanical substitution on through-hole PCBs without layout modification.

Q: What are the key differences between these two parts?

A: The primary differences are manufacturer identity and operating temperature range. BC337-40BK specifies an operating temperature range of −55°C to 150°C, while BC33740BU specifies a maximum of 150°C. RoHS compliance documentation differs between manufacturers. All electrical performance parameters are identical.

Q: Are there packaging differences between BC33740BU and BC337-40BK?

A: Both devices use TO-92-3 (TO-226-3) through-hole packaging. BC33740BU is supplied in bulk packaging, while BC337-40BK is supplied in box packaging. Physical component dimensions and pin configuration are identical, ensuring direct PCB compatibility.

Q: What compliance certifications apply to each part?

A: BC33740BU carries RoHS3 compliance and REACH Unaffected status. BC337-40BK RoHS status is listed as not applicable, and REACH status is vendor undefined. Both devices are classified under ECCN EAR99 for export control purposes.

Q: Can these parts be used interchangeably in high-frequency applications?

A: Yes. Both devices specify identical transition frequency of 100 MHz, supporting equivalent performance in switching and amplification circuits operating within this frequency range.

Q: What inventory considerations should guide part selection?

A: BC33740BU has 5861 units in stock, while BC337-40BK has 5500 units available. Selection should be based on supply chain strategy, procurement lead times, and manufacturer preference rather than inventory levels alone, as both quantities support production requirements.

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