BC640BU Equivalent & Substitute Parts

Part Overview

The BC640BU is a PNP bipolar junction transistor manufactured by onsemi, designed for general-purpose switching and amplification applications. This device features an 80 V collector-emitter breakdown voltage rating, 1 A maximum collector current, and 1 W power dissipation capability in a Through Hole TO-92-3 package. The BC640BU is classified as obsolete, making identification of equivalent substitute parts essential for ongoing design support and procurement continuity.

Key Parameters

Parameter	Value
Transistor Type	PNP
Current - Collector (Ic) (Max)	1 A
Voltage - Collector Emitter Breakdown (Max)	80 V
Vce Saturation (Max) @ Ib, Ic	500mV @ 50mA, 500mA
Current - Collector Cutoff (Max)	100nA (ICBO)
DC Current Gain (hFE) (Min) @ Ic, Vce	40 @ 150mA, 2V
Power - Max	1 W
Frequency - Transition	100MHz
Operating Temperature (TJ)	150°C
Mounting Type	Through Hole
Package / Case	TO-92-3 (TO-226AA)

Substitute Part Grouping Explanation

Substitution of the BC640BU is determined by electrical and mechanical parameter equivalence. The critical parameters governing substitution are:

Transistor Type: PNP configuration
Current Rating: 1 A maximum collector current
Voltage Rating: 80 V collector-emitter breakdown voltage
Saturation Characteristics: 500mV @ 50mA, 500mA
Current Gain: Minimum 40 hFE @ 150mA, 2V
Power Dissipation: 1 W maximum
Frequency Response: 100MHz transition frequency
Package: TO-92-3 Through Hole configuration

The BC640TA meets all electrical specifications and mechanical requirements identical to the BC640BU. Both devices share the same base product number (BC640) and are manufactured by onsemi. The primary distinction is product status and packaging format.

Parameter Comparison

Parameter	BC640BU	BC640TA
Transistor Type	PNP	PNP
Current - Collector (Ic) (Max)	1 A	1 A
Voltage - Collector Emitter Breakdown (Max)	80 V	80 V
Vce Saturation (Max) @ Ib, Ic	500mV @ 50mA, 500mA	500mV @ 50mA, 500mA
Current - Collector Cutoff (Max)	100nA (ICBO)	100nA (ICBO)
DC Current Gain (hFE) (Min) @ Ic, Vce	40 @ 150mA, 2V	40 @ 150mA, 2V
Power - Max	1 W	1 W
Frequency - Transition	100MHz	100MHz
Operating Temperature (TJ)	150°C	150°C
Mounting Type	Through Hole	Through Hole
Package / Case	TO-92-3 (TO-226AA)	TO-92-3 (TO-226AA) Formed Leads
Product Status	Obsolete	Active
REACH Status	REACH Unaffected	REACH Unaffected
ECCN	EAR99	EAR99

Engineering Selection Recommendations

The BC640TA is the direct substitute for the BC640BU. Both devices are manufactured by onsemi and provide identical electrical performance across all specified parameters. The BC640TA is classified as Active product status, ensuring ongoing availability and manufacturing support, whereas the BC640BU is obsolete.

The BC640TA carries ROHS3 compliance certification, providing regulatory advantage for new designs and procurement. Both parts maintain REACH Unaffected status and EAR99 export classification. The packaging designation includes "Formed Leads" for the BC640TA, indicating pre-formed lead geometry suitable for standard through-hole PCB assembly processes.

Selection of the BC640TA over the BC640BU is supported by active product status and regulatory compliance certifications, with no electrical or mechanical performance trade-offs.

Frequently Asked Questions (FAQ)

Q: Can the BC640TA directly replace the BC640BU in existing designs?

A: Yes. The BC640TA provides identical electrical specifications across all parameters including current rating, voltage rating, gain characteristics, and frequency response. Both devices use the TO-92-3 Through Hole package with compatible lead configurations.

Q: What is the significance of the "Formed Leads" designation on the BC640TA?

A: Formed Leads indicates that the BC640TA features pre-shaped lead geometry optimized for standard through-hole PCB assembly. This is a manufacturing specification that does not affect electrical performance or functional compatibility.

Q: Why is the BC640BU listed as obsolete?

A: Obsolete status indicates that the BC640BU is no longer in active production. The BC640TA serves as the current production equivalent with identical electrical and mechanical specifications.

Q: Are there compliance differences between BC640BU and BC640TA?

A: The BC640TA includes ROHS3 compliance certification, whereas the BC640BU does not specify this certification. Both devices maintain REACH Unaffected status and EAR99 export classification. For applications requiring ROHS3 compliance, the BC640TA is the appropriate selection.

Q: What are the critical parameters for substitution compatibility?

A: Substitution compatibility is determined by matching transistor type (PNP), collector current rating (1 A), collector-emitter breakdown voltage (80 V), saturation characteristics (500mV @ 50mA, 500mA), DC current gain (40 hFE minimum @ 150mA, 2V), power dissipation (1 W), transition frequency (100MHz), and package type (TO-92-3 Through Hole).

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