BC337RL1G Equivalent & Substitute Parts

Part Overview

The BC337RL1G is an NPN bipolar junction transistor manufactured by onsemi, rated for 45V collector-emitter breakdown voltage and 800mA maximum collector current in a through-hole TO-92 package. This device is classified as obsolete, necessitating identification of equivalent and substitute components for ongoing design requirements and production continuity. Active alternatives with comparable electrical characteristics and mechanical compatibility are available from multiple manufacturers.

Key Parameters

Parameter	BC337RL1G
Transistor Type	NPN
Voltage - Collector Emitter Breakdown (Max)	45 V
Current - Collector (Ic) (Max)	800 mA
Power - Max	625 mW
Frequency - Transition	210 MHz
DC Current Gain (hFE) (Min) @ Ic, Vce	100 @ 100mA, 1V
Vce Saturation (Max) @ Ib, Ic	700mV @ 50mA, 500mA
Operating Temperature	-55°C ~ 150°C (TJ)
Mounting Type	Through Hole
Package / Case	TO-226-3, TO-92-3 Long Body (Formed Leads)

Substitute Part Grouping Explanation

Substitution of the BC337RL1G is determined by equivalence in the following critical parameters: NPN transistor type, 45V collector-emitter breakdown voltage rating, 800mA maximum collector current, 625mW power dissipation, TO-92 through-hole package compatibility, and DC current gain minimum of 100 at specified test conditions. Substitute parts are grouped into two categories:

Direct Equivalents (Identical Electrical and Mechanical Specifications): Parts meeting all primary electrical parameters (45V, 800mA, 625mW) with TO-92 through-hole mounting and compatible saturation characteristics.

Functional Alternatives (Modified Specifications Within Application Tolerance): Parts with reduced collector current (600mA) or different transition frequency while maintaining 45V rating, TO-92 package, and 625mW power rating. These are suitable for applications where the lower current rating does not constrain circuit operation.

Package Variants (Different Mounting Technology): Surface-mount alternatives in SOT-23 package with reduced current and power ratings, applicable only to designs permitting package substitution.

Parameter Comparison

Part Number	Manufacturer	Transistor Type	Vce Breakdown (Max)	Ic (Max)	Power (Max)	Frequency - Transition	hFE (Min) @ Ic, Vce	Package	Product Status
BC337RL1G	onsemi	NPN	45 V	800 mA	625 mW	210 MHz	100 @ 100mA, 1V	TO-92-3	Obsolete
BC337-25-AP	Micro Commercial Co	NPN	45 V	800 mA	625 mW	210 MHz	160 @ 100mA, 1V	TO-92-3	Obsolete
BC33716TA	Fairchild Semiconductor	NPN	45 V	800 mA	625 mW	100 MHz	100 @ 100mA, 1V	TO-92-3	Active
BC33725TA	onsemi	NPN	45 V	800 mA	625 mW	100 MHz	160 @ 100mA, 1V	TO-92-3	Active
BC33725TAR	onsemi	NPN	45 V	800 mA	625 mW	100 MHz	160 @ 100mA, 1V	TO-92-3	Active
BC33725TFR	Fairchild Semiconductor	NPN	45 V	800 mA	625 mW	100 MHz	160 @ 100mA, 1V	TO-92-3	Active
BC33740TA	onsemi	NPN	45 V	800 mA	625 mW	100 MHz	250 @ 100mA, 1V	TO-92-3	Active
2N4401BU	onsemi	NPN	40 V	600 mA	625 mW	250 MHz	100 @ 150mA, 1V	TO-92-3	Active
BC817-25LT1G	onsemi	NPN	45 V	500 mA	300 mW	100 MHz	160 @ 100mA, 1V	SOT-23-3	Active

Engineering Selection Recommendations

Primary Substitutes (Recommended for Direct Replacement):

BC33725TA, BC33725TAR, and BC33725TFR are active production parts maintaining identical electrical specifications to BC337RL1G: 45V breakdown voltage, 800mA collector current, 625mW power dissipation, and TO-92-3 through-hole package. These parts feature higher DC current gain (160 vs. 100), which provides improved circuit stability and reduced base drive requirements. All three are ROHS3 compliant and carry REACH Unaffected status.

BC33716TA (Fairchild Semiconductor) provides equivalent electrical performance with identical voltage, current, and power ratings in TO-92-3 package. This part maintains the minimum hFE specification of 100 at test conditions, matching the original BC337RL1G characteristic.

BC33740TA offers the highest DC current gain (250 @ 100mA, 1V) among active substitutes while maintaining all other electrical parameters. This part is suitable for applications benefiting from increased current amplification.

Secondary Substitutes (Application-Dependent):

2N4401BU is an active onsemi product with reduced collector current rating (600mA vs. 800mA) and lower breakdown voltage (40V vs. 45V). This part is applicable only to circuits where maximum current and voltage margins are not critical design constraints. The higher transition frequency (250MHz) may provide performance advantages in high-frequency applications.

Package Variant (Surface Mount Alternative):

BC817-25LT1G is a surface-mount SOT-23-3 package alternative with reduced current (500mA) and power (300mW) ratings. This part is suitable only for designs permitting package substitution and where reduced current capacity is acceptable.

Obsolete Parts (Not Recommended for New Designs):

BC337-25-AP and BC337RL1G are both classified as obsolete. BC337-25-AP shares identical electrical specifications with BC337RL1G but carries obsolete status. New designs should utilize active production alternatives listed above.

Frequently Asked Questions (FAQ)

Q: Can BC33725TA directly replace BC337RL1G in existing designs?

A: Yes. BC33725TA maintains identical voltage (45V), current (800mA), power (625mW), and package (TO-92-3) specifications. The higher DC current gain (160 vs. 100) is a performance enhancement that does not compromise compatibility. Pin configuration and mechanical dimensions are identical.

Q: What is the difference between BC33725TA, BC33725TAR, and BC33725TFR?

A: These three parts are electrically identical with matching specifications. BC33725TA and BC33725TAR are onsemi products supplied in cut tape packaging. BC33725TFR is the Fairchild Semiconductor equivalent. Selection between these parts depends on supplier availability and packaging preference (cut tape vs. alternative formats).

Q: Is 2N4401BU a suitable replacement for BC337RL1G?

A: 2N4401BU is a functional alternative with reduced specifications: 40V breakdown voltage (vs. 45V) and 600mA collector current (vs. 800mA). This part is suitable only for applications where the lower voltage and current ratings do not constrain circuit operation. Circuits designed for maximum BC337RL1G ratings may not operate reliably with 2N4401BU.

Q: Can BC817-25LT1G replace BC337RL1G?

A: BC817-25LT1G is a surface-mount SOT-23-3 package part with reduced current (500mA) and power (300mW) ratings. This part is suitable only for designs permitting package substitution from through-hole TO-92 to surface-mount SOT-23. The reduced current and power ratings limit applicability to lower-power circuits.

Q: What is the significance of DC current gain (hFE) differences among substitute parts?

A: DC current gain determines the base current required to achieve specified collector current. BC337RL1G specifies minimum hFE of 100 at 100mA collector current. Substitute parts with higher hFE (160 or 250) require less base drive current to achieve the same collector current, improving circuit efficiency and reducing base resistor values. Higher hFE does not degrade circuit performance in standard amplifier configurations.

Q: Are all substitute parts ROHS3 compliant?

A: BC33725TA, BC33725TAR, BC33740TA, and 2N4401BU are ROHS3 compliant. BC33716TA and BC33725TFR (Fairchild products) do not specify ROHS status in provided data. BC817-25LT1G is ROHS3 compliant. Compliance requirements should be verified against specific application standards.

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

A: BC337RL1G operates from -55°C to 150°C (TJ). BC33725TA, BC33725TAR, BC33740TA, BC33716TA, and BC33725TFR specify 150°C maximum (TJ) without lower temperature specification. 2N4401BU operates -55°C to 150°C (TJ). BC817-25LT1G operates -65°C to 150°C (TJ), providing extended low-temperature capability.

Q: Can multiple substitute parts be used interchangeably in production?

A: BC33725TA, BC33725TAR, BC33725TFR, BC33716TA, and BC33740TA are fully interchangeable from electrical and mechanical perspectives. All maintain 45V, 800mA, 625mW, and TO-92-3 specifications. Production designs may source from any of these active parts based on supplier availability and cost optimization. 2N4401BU and BC817-25LT1G require circuit re-evaluation due to reduced ratings and package differences.

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