BC327 Equivalent & Substitute Parts

Part Overview

The BC327 is a PNP bipolar junction transistor manufactured by onsemi, rated for 45 V collector-emitter breakdown voltage and 800 mA maximum collector current. The device is packaged in a TO-92 through-hole configuration and is classified as obsolete. Due to its obsolete product status, equivalent substitute parts with matching or superior electrical characteristics are necessary for ongoing design support and production continuity. Substitute parts listed maintain functional compatibility within the specified electrical and mechanical parameters.

Key Parameters

Parameter	BC327 Specification
Transistor Type	PNP
Collector Current (Ic) Max	800 mA
Collector-Emitter Breakdown Voltage (Max)	45 V
Power Dissipation (Max)	625 mW
Transition Frequency	260 MHz
Operating Temperature Range	-55°C to 150°C
Package Type	TO-92 (TO-226-3)
Mounting Type	Through Hole
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitute parts for the BC327 are selected based on the following critical parameters that determine functional equivalence:

Primary Matching Criteria:

Transistor type: PNP configuration
Collector-emitter breakdown voltage: 45 V or higher
Maximum collector current: 800 mA or higher
Power dissipation: 625 mW or higher
Package type: TO-92 through-hole configuration
Operating temperature range: -55°C to 150°C or compatible subset

Substitution Logic: Parts meeting or exceeding these parameters in all categories are classified as direct substitutes. Parts with lower maximum ratings in any critical parameter are not suitable for direct substitution. The BC32740BU and BC32725BU maintain identical electrical ratings to the BC327 while offering active product status. The 2N4403BU provides functional substitution with reduced maximum collector current (600 mA vs. 800 mA) and lower breakdown voltage (40 V vs. 45 V), requiring application-level verification of current and voltage headroom.

Parameter Comparison

Parameter	BC327	BC32740BU	BC32725BU	2N4403BU
Manufacturer	onsemi	onsemi	onsemi	Fairchild Semiconductor
Transistor Type	PNP	PNP	PNP	PNP
Ic (Max)	800 mA	800 mA	800 mA	600 mA
Vce Breakdown (Max)	45 V	45 V	45 V	40 V
Vce Saturation (Max) @ Ib, Ic	700mV @ 50mA, 500mA	700mV @ 50mA, 500mA	700mV @ 50mA, 500mA	750mV @ 50mA, 500mA
Power Dissipation (Max)	625 mW	625 mW	625 mW	625 mW
Transition Frequency	260 MHz	100 MHz	100 MHz	200 MHz
Operating Temperature	-55°C to 150°C	-55°C to 150°C	-55°C to 150°C	-55°C to 150°C
Package	TO-92 (TO-226-3)	TO-92-3 (TO-226-3)	TO-92-3 (TO-226-3)	TO-92-3 (TO-226-3)
Product Status	Obsolete	Active	Active	Active
RoHS Compliance	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	Not specified

Engineering Selection Recommendations

BC32740BU (onsemi): This part is the primary substitute for BC327. It maintains identical electrical specifications (45 V, 800 mA, 625 mW) with active product status and ROHS3 compliance. The transition frequency is reduced to 100 MHz compared to the BC327's 260 MHz; this reduction is acceptable for applications not requiring the higher frequency performance of the original part. Pin configuration and TO-92-3 package are directly compatible.

BC32725BU (onsemi): This part is an equivalent substitute with identical electrical ratings (45 V, 800 mA, 625 mW) and active product status. ROHS3 compliance is confirmed. Transition frequency is 100 MHz. This part is suitable for direct replacement in applications where the reduced frequency response does not impact circuit performance.

2N4403BU (Fairchild Semiconductor): This part provides functional substitution with reduced maximum ratings. Maximum collector current is 600 mA (vs. 800 mA) and breakdown voltage is 40 V (vs. 45 V). The transition frequency is 200 MHz. This part is suitable only for applications where the circuit design operates within the reduced current and voltage specifications. Vce saturation is slightly higher at 750 mV. Active product status and standard package compatibility are confirmed.

Frequently Asked Questions (FAQ)

Q: Can BC32740BU or BC32725BU be used as direct pin-for-pin replacements for BC327?

A: Yes. Both parts are packaged in TO-92-3 configuration with identical pinout. No circuit board modifications are required for physical installation.

Q: What is the primary difference between BC32740BU and BC32725BU?

A: Both parts have identical electrical specifications. The primary difference is DC current gain (hFE): BC32740BU specifies 250 @ 100mA, 1V while BC32725BU specifies 160 @ 100mA, 1V. Selection depends on circuit requirements for current gain.

Q: Can 2N4403BU replace BC327 in all applications?

A: No. The 2N4403BU has reduced maximum ratings: 600 mA collector current (vs. 800 mA) and 40 V breakdown voltage (vs. 45 V). It is suitable only for applications where circuit design operates within these lower specifications.

Q: What is the impact of the reduced transition frequency in BC32740BU and BC32725BU?

A: Both substitute parts operate at 100 MHz transition frequency compared to BC327's 260 MHz. For applications operating at frequencies below 100 MHz, this reduction has no functional impact. For high-frequency switching applications, the reduced frequency response must be evaluated against circuit requirements.

Q: Are all substitute parts RoHS compliant?

A: BC32740BU and BC32725BU are ROHS3 compliant. The original BC327 is RoHS non-compliant. The 2N4403BU compliance status is not specified in available documentation.

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

A: BC32740BU, BC32725BU, and 2N4403BU all operate across -55°C to 150°C, matching the BC327 specification.

Q: Are there any package differences between BC327 and the substitute parts?

A: All parts use TO-92 through-hole packaging. BC327 is specified as TO-226-3 or TO-92-3 Long Body. Substitute parts are specified as TO-92-3 (TO-226-3) or TO-226-3. Physical dimensions and pin spacing are compatible for standard PCB layouts.

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