BC33725BU Equivalent & Substitute Parts

Part Overview

The BC33725BU 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 and collector-emitter breakdown voltage of 45 V, with a maximum power dissipation of 625 mW. The part is currently in active production status with substantial inventory availability. Equivalent and substitute parts are identified to provide design flexibility, support supply chain continuity, and accommodate different packaging or sourcing preferences while maintaining electrical and mechanical compatibility.

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	700 mV @ 50 mA, 500 mA	—
Current - Collector Cutoff (Max)	100	nA
DC Current Gain (hFE) (Min) @ Ic, Vce	160 @ 100 mA, 1 V	—
Power - Max	625	mW
Frequency - Transition	100	MHz
Mounting Type	Through Hole	—
Package / Case	TO-226-3, TO-92-3 (TO-226AA)	—
Operating Temperature (Max)	150	°C (TJ)

Substitute Part Grouping Explanation

Substitute parts for the BC33725BU are identified based on strict electrical and mechanical parameter matching. The substitution criteria are:

Transistor Type: NPN configuration
Current - Collector (Ic) (Max): 800 mA
Voltage - Collector Emitter Breakdown (Max): 45 V
Vce Saturation (Max) @ Ib, Ic: 700 mV @ 50 mA, 500 mA
Current - Collector Cutoff (Max): 100 nA
DC Current Gain (hFE) (Min) @ Ic, Vce: 160 @ 100 mA, 1 V
Power - Max: 625 mW
Frequency - Transition: 100 MHz
Mounting Type: Through Hole
Package / Case: TO-226-3, TO-92-3 (TO-226AA)

Parts meeting all these parameters are classified as parametric equivalents and are suitable for direct substitution in circuit designs. Packaging format (bulk versus box) and inventory levels do not affect electrical compatibility.

Parameter Comparison

Parameter	BC33725BU (onsemi)	BC337-25BK (Diotec)	BC33725BU (Fairchild)
Transistor Type	NPN	NPN	NPN
Current - Collector (Ic) (Max)	800 mA	800 mA	800 mA
Voltage - Collector Emitter Breakdown (Max)	45 V	45 V	45 V
Vce Saturation (Max) @ Ib, Ic	700 mV @ 50 mA, 500 mA	700 mV @ 50 mA, 500 mA	700 mV @ 50 mA, 500 mA
Current - Collector Cutoff (Max)	100 nA	100 nA	100 nA
DC Current Gain (hFE) (Min) @ Ic, Vce	160 @ 100 mA, 1 V	160 @ 100 mA, 1 V	160 @ 100 mA, 1 V
Power - Max	625 mW	625 mW	625 mW
Frequency - Transition	100 MHz	100 MHz	100 MHz
Mounting Type	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
Operating Temperature (Max)	150°C (TJ)	150°C (TJ)	150°C (TJ)
Product Status	Active	Active	Active

Engineering Selection Recommendations

All identified substitute parts maintain identical electrical specifications and mechanical compatibility with the BC33725BU. Selection among equivalent parts should be based on the following factors:

Compliance and Certifications: The BC33725BU (onsemi) and BC33725BU (Fairchild) are both ROHS3 compliant. The BC337-25BK (Diotec) RoHS status is listed as not applicable. All three parts carry EAR99 ECCN classification and share the same HTSUS code (8541.21.0075).

Inventory and Availability: The onsemi BC33725BU and Fairchild BC33725BU each maintain 25,400 pieces in stock. The Diotec BC337-25BK has 5,736 pieces available.

Packaging Format: The onsemi and Fairchild versions are supplied in bulk packaging, while the Diotec BC337-25BK is supplied in box packaging. This distinction affects procurement and handling but does not impact electrical performance.

Operating Temperature Range: The onsemi and Fairchild versions specify a maximum operating temperature of 150°C. The Diotec BC337-25BK specifies an operating temperature range of −55°C to 150°C, providing extended low-temperature capability.

Frequently Asked Questions (FAQ)

Q: Can BC337-25BK (Diotec) be used as a direct replacement for BC33725BU (onsemi)?

A: Yes. The BC337-25BK meets all electrical and mechanical parameters required for substitution, including collector current, breakdown voltage, saturation characteristics, current gain, power dissipation, transition frequency, and through-hole TO-92-3 package compatibility.

Q: What is the difference between the onsemi BC33725BU and Fairchild BC33725BU?

A: Both parts are electrically and mechanically identical. The difference is manufacturer origin. Both are ROHS3 compliant, active products with identical electrical specifications and maximum operating temperature of 150°C.

Q: Does the Diotec BC337-25BK have different electrical performance?

A: No. The Diotec BC337-25BK maintains identical electrical specifications across all critical parameters: 800 mA maximum collector current, 45 V breakdown voltage, 625 mW power dissipation, 100 MHz transition frequency, and 160 minimum DC current gain. The extended operating temperature range (−55°C to 150°C) does not alter performance within standard operating conditions.

Q: Are there packaging differences between these parts?

A: The onsemi and Fairchild versions are supplied in bulk packaging. The Diotec BC337-25BK is supplied in box packaging. Both use the TO-92-3 through-hole package format, ensuring identical PCB footprint and mounting compatibility.

Q: Which part should be selected for new designs?

A: Selection should be based on supply chain requirements, compliance certifications, and packaging preferences. All three parts are active products with identical electrical performance and mechanical compatibility. The Diotec BC337-25BK offers extended low-temperature operation if required by application specifications.

Q: Are these parts RoHS compliant?

A: The onsemi BC33725BU and Fairchild BC33725BU are ROHS3 compliant. The Diotec BC337-25BK RoHS status is listed as not applicable. Compliance requirements should be verified against specific application and regional regulations.

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