BC337-040 Equivalent & Substitute Parts

Part Overview

The BC337-040 is an NPN bipolar junction transistor manufactured by onsemi, rated for 45 V collector-emitter breakdown voltage and 800 mA maximum collector current. This device is packaged in the TO-92 (TO-226-3) through-hole configuration and is suitable for general-purpose switching and amplification applications in the 625 mW power class.

The BC337-040 is classified as obsolete. Equivalent and substitute parts are necessary to maintain design continuity and ensure component availability for production, repair, and new designs requiring compatible NPN transistor functionality within the specified electrical and mechanical parameters.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	45	V
Current - Collector (Ic) (Max)	800	mA
Power - Max	625	mW
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	—
Frequency - Transition	210	MHz
Operating Temperature	-55 to 150	°C
Mounting Type	Through Hole	—
Package / Case	TO-226-3, TO-92-3 Long Body	—

Substitute Part Grouping Explanation

Substitution of the BC337-040 is determined by electrical and mechanical compatibility across the following critical parameters:

Electrical Compatibility Criteria:

Transistor Type: NPN (required match)
Voltage - Collector Emitter Breakdown (Max): 45 V minimum
Current - Collector (Ic) (Max): 800 mA minimum
Power - Max: 625 mW minimum
Vce Saturation: 700mV @ 50mA, 500mA (or lower)
Current - Collector Cutoff (Max): 100 nA or lower
DC Current Gain (hFE): 100 or higher at specified conditions
Operating Temperature Range: Must accommodate -55°C to 150°C or equivalent

Mechanical Compatibility Criteria:

Mounting Type: Through Hole (required match)
Package / Case: TO-92-3 or TO-226-3 compatible footprint

Substitute parts are grouped into two categories:

Category 1: Direct Electrical Equivalents (100 MHz transition frequency) Parts BC33716BU, BC33725BU, and BC33740BU meet all electrical requirements with reduced transition frequency (100 MHz vs. 210 MHz). These parts are suitable for applications where the lower frequency specification does not impact circuit performance.

Category 2: Enhanced Performance Substitute (150 MHz transition frequency, increased current rating) Part ZTX450 exceeds the BC337-040 specifications in collector current (1 A vs. 800 mA) and power dissipation (1 W vs. 625 mW), with compatible voltage and temperature ratings. This part is suitable for applications requiring higher current capacity or thermal margin.

Category 3: Direct Equivalent (210 MHz transition frequency) Part BC337-25-AP maintains the original 210 MHz transition frequency specification and is electrically identical to the BC337-040.

Parameter Comparison

Parameter	BC337-040 (Main)	BC33716BU	BC33725BU	BC33740BU	BC337-25-AP	ZTX450
Manufacturer	onsemi	Fairchild Semiconductor	Fairchild Semiconductor	onsemi	Micro Commercial Co	Diodes Incorporated
Transistor Type	NPN	NPN	NPN	NPN	NPN	NPN
Voltage - Collector Emitter Breakdown (Max)	45 V	45 V	45 V	45 V	45 V	45 V
Current - Collector (Ic) (Max)	800 mA	800 mA	800 mA	800 mA	800 mA	1 A
Power - Max	625 mW	625 mW	625 mW	625 mW	625 mW	1 W
Vce Saturation (Max) @ Ib, Ic	700mV @ 50mA, 500mA	700mV @ 50mA, 500mA	700mV @ 50mA, 500mA	700mV @ 50mA, 500mA	700mV @ 50mA, 500mA	250mV @ 15mA, 150mA
Current - Collector Cutoff (Max)	100 nA	100 nA	100 nA	100 nA	200 nA	100 nA
DC Current Gain (hFE) (Min) @ Ic, Vce	250 @ 100mA, 1V	100 @ 100mA, 1V	160 @ 100mA, 1V	250 @ 100mA, 1V	160 @ 100mA, 1V	100 @ 150mA, 10V
Frequency - Transition	210 MHz	100 MHz	100 MHz	100 MHz	210 MHz	150 MHz
Operating Temperature	-55 to 150°C	to 150°C	to 150°C	to 150°C	-55 to 150°C	-55 to 200°C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	TO-226-3, TO-92-3	TO-226-3, TO-92-3	TO-226-3, TO-92-3	TO-226-3, TO-92-3	TO-226-3, TO-92-3	E-Line-3 (TO-92 compatible)
Product Status	Obsolete	Active	Active	Active	Obsolete	Active
RoHS Status	Non-compliant	Not specified	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Replacement (Electrical and Frequency Match): BC337-25-AP is the direct equivalent to BC337-040, maintaining identical transition frequency (210 MHz) and DC current gain specifications. This part is classified as obsolete but remains available in inventory. Selection of BC337-25-AP is appropriate when the original 210 MHz specification is a design requirement.

For Active Component Availability (100 MHz Transition Frequency): BC33740BU (onsemi) is recommended as the primary substitute. This part is manufactured by the original equipment manufacturer (onsemi), is ROHS3 compliant, and maintains identical electrical specifications for voltage, current, power, and saturation characteristics. The transition frequency is reduced to 100 MHz, which is acceptable for applications not requiring the full 210 MHz bandwidth. BC33740BU is currently in active production status with substantial inventory availability (5,861 units).

BC33725BU (Fairchild Semiconductor) and BC33716BU (Fairchild Semiconductor) are alternative substitutes with identical voltage, current, and power ratings. Both are active products with higher inventory levels (25,400 and 73,196 units respectively). DC current gain specifications differ (160 and 100 respectively), which may affect circuit biasing calculations.

For Enhanced Performance Applications: ZTX450 (Diodes Incorporated) is suitable for applications requiring higher collector current (1 A vs. 800 mA) or increased power dissipation capability (1 W vs. 625 mW). This part maintains the 45 V voltage specification and extends the operating temperature range to 200°C. The transition frequency is 150 MHz, and saturation voltage is lower (250 mV), indicating improved switching performance. ZTX450 is ROHS3 compliant and currently in active production.

Compliance Considerations: The BC337-040 is RoHS non-compliant. For new designs or applications requiring RoHS compliance, BC33740BU, BC337-25-AP, or ZTX450 are compliant alternatives. BC33740BU is the recommended choice for RoHS-compliant applications requiring the closest electrical match to the original specification.

Frequently Asked Questions (FAQ)

Q: Can BC33716BU or BC33725BU be used as direct replacements for BC337-040?

A: Yes, both parts are electrically compatible substitutes. They meet the voltage (45 V), current (800 mA), power (625 mW), and saturation voltage specifications of the BC337-040. The transition frequency is reduced from 210 MHz to 100 MHz. This reduction does not affect applications operating below 100 MHz. DC current gain differs between parts (BC33716BU: 100, BC33725BU: 160, BC337-040: 250), which may require circuit biasing adjustments.

Q: What is the difference between BC33740BU and BC33725BU?

A: Both parts are manufactured to the same electrical specifications (45 V, 800 mA, 625 mW, 100 MHz). The primary differences are manufacturer (BC33740BU: onsemi; BC33725BU: Fairchild Semiconductor) and DC current gain (BC33740BU: 250; BC33725BU: 160). BC33740BU is manufactured by the original BC337-040 supplier and is ROHS3 compliant.

Q: Is ZTX450 a suitable replacement for BC337-040?

A: ZTX450 is a compatible substitute with enhanced specifications. It maintains the 45 V voltage rating and exceeds the current (1 A vs. 800 mA) and power (1 W vs. 625 mW) ratings. The transition frequency is 150 MHz, which is lower than the BC337-040 (210 MHz) but higher than the 100 MHz alternatives. ZTX450 is suitable for applications where higher current capacity or thermal margin is beneficial. The E-Line package is mechanically compatible with TO-92 footprints.

Q: Does the reduced transition frequency of 100 MHz substitutes affect circuit performance?

A: The transition frequency reduction from 210 MHz to 100 MHz affects high-frequency switching and amplification performance. For applications operating below 100 MHz, the reduction has no functional impact. For applications requiring the full 210 MHz bandwidth, BC337-25-AP or ZTX450 (150 MHz) are appropriate selections.

Q: Are all substitute parts RoHS compliant?

A: No. The BC337-040 is RoHS non-compliant. BC33740BU, BC337-25-AP, and ZTX450 are ROHS3 compliant. BC33716BU and BC33725BU do not specify RoHS status in available documentation. For applications requiring RoHS compliance, BC33740BU is the recommended substitute.

Q: Can BC337-25-AP be used instead of BC337-040?

A: Yes. BC337-25-AP is electrically and functionally identical to BC337-040, maintaining the 210 MHz transition frequency and 250 DC current gain specification. Both parts are classified as obsolete. BC337-25-AP is available in cut tape packaging and is ROHS3 compliant.

Q: What is the operating temperature range difference between substitutes?

A: BC337-040, BC337-25-AP, and ZTX450 operate from -55°C to 150°C (or 200°C for ZTX450). BC33716BU, BC33725BU, and BC33740BU specify operation to 150°C without a lower temperature limit in provided documentation. For applications requiring -55°C operation, BC337-040, BC337-25-AP, or ZTX450 are appropriate selections.

Q: Are there packaging differences between substitute parts?

A: All substitute parts use through-hole mounting in TO-92-compatible packages. BC33740BU, BC33725BU, and BC33716BU use TO-92-3 (TO-226AA) packaging. BC337-25-AP uses TO-92 with formed leads. ZTX450 uses E-Line-3 packaging, which is mechanically compatible with TO-92 footprints. All parts are suitable for identical PCB layouts.

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