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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi BC308_J35Z

Name: BC308_J35Z
Brand: onsemi
SKU: BC308_J35Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC308_J35Z

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: BC308_J35Z.pdf

Description:: TRANS PNP 25V 0.1A TO-92-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

BC308_J35Z from Fairchild Semiconductor is a PNP epitaxial silicon transistor designed for low-noise amplifier and general-purpose switching applications, with V_CEO = –25 V, I_C = –100 mA, P_C = 500 mW, h_FE = 120–800 (Class A/B/C), and f_T = 130 MHz - used in audio preamplifier stages and relay driver circuits.

For engineers reviewing the BC308_J35Z datasheet, pinout, applications, or equivalent options, key selection considerations include its TO-92 package, PNP polarity, DC current gain classification, saturation voltage at defined drive conditions, and noise figure performance in low-signal amplification.

Technical Context

The BC308_J35Z operates as a medium-speed, medium-power PNP bipolar junction transistor optimized for linear amplification and saturated switching. Its h_FE range (120–800) supports both high-gain small-signal use and robust current-switching roles, while V_CE(sat) ≤ –0.5 V at I_C = –10 mA / I_B = –0.5 mA enables efficient low-loss switching.

It features low output capacitance (C_ob = 6 pF at V_CB = –10 V) and input capacitance (C_ib = 12 pF at V_EB = –0.5 V), supporting stable operation up to 130 MHz f_T; noise figure is 2 dB at 1 kHz (BC307/308 variant), confirming suitability for audio-frequency amplification.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	–25 V: Maximum safe collector-emitter voltage under open-base condition; defines upper rail limit in PNP switch/amplifier designs.
I_C (DC)	–100 mA: Continuous collector current rating; sets maximum load-handling capability in relay drivers or LED sinks.
P_C	500 mW: Total power dissipation at T_A = 25°C; determines thermal derating requirements on PCB without heatsink.
h_FE	120–800 (Class A/B/C): DC current gain spread; enables selection of matched units for differential pairs or consistent biasing across production lots.
f_T	130 MHz: Current gain–bandwidth product; confirms usable gain up to ~10–20 MHz in common-emitter amplifier configurations.
V_CE(sat)	–0.5 V (I_C = –10 mA, I_B = –0.5 mA): Low saturation voltage ensures minimal power loss and heat generation in switching applications.
NF	2 dB @ 1 kHz: Measured noise figure; qualifies BC308_J35Z for low-noise preamplifier stages in audio signal chains.

Pinout & Package

BC308_J35Z is housed in a standard through-hole TO-92 package (3.60 × 4.58 × 14.47 mm), with lead spacing matching JEDEC TO-92 outline. Pin identification follows EIAJ standard: Lead 1 = Collector, Lead 2 = Base, Lead 3 = Emitter.

Pin/Terminal	Circuit Role	Design Meaning
1	Collector	Primary current sink terminal; connects to negative supply rail in PNP common-emitter amplifier or switch configurations.
2	Base	Control electrode; requires negative base current relative to emitter to turn on; bias network design must respect V_BE(on) ≈ –0.62 V.
3	Emitter	Current source terminal; typically tied to ground or positive rail; serves as reference node for bias and signal return paths.

Key Features

Feature	Design Value
Low-noise amplification	2 dB noise figure at 1 kHz enables use in microphone preamps and sensor signal conditioning where SNR preservation is critical.
Wide h_FE classification range	Three gain bins (A/B/C) allow selective binning for matched-pair circuits or predictable bias point setting in production.
High f_T bandwidth	130 MHz f_T supports stable small-signal amplification up to mid-VHF frequencies, suitable for RF detector stages and oscillator active devices.
Low V_CE(sat)	–0.5 V saturation voltage at moderate drive reduces conduction loss and improves efficiency in discrete logic-level switches and analog multiplexers.
TO-92 mechanical compatibility	Standard footprint enables drop-in replacement in legacy designs using BC307/BC309 and simplifies manual assembly and rework.

Applications

Audio Preamp Stage	Relay Driver Circuit
Use Scenario: Amplifying weak signals from electret microphones or piezoelectric sensors before ADC sampling. IC Role / Device Role / Timing Role: Small-signal PNP amplifier in common-emitter configuration with emitter degeneration for linearity. Use Value: 2 dB noise figure and h_FE ≥ 120 ensure high SNR and stable gain control without added op-amp complexity.	Use Scenario: Driving 5–12 V coil relays from microcontroller GPIO pins via level-shifting interface. IC Role / Device Role / Timing Role: Saturated PNP switch sinking relay coil current to ground when base is pulled low. Use Value: V_CE(sat) ≤ –0.5 V minimizes power dissipation and coil voltage drop, ensuring reliable relay pull-in at low drive currents.
LED Current Sink	Differential Pair Input Stage
Use Scenario: Controlling brightness of indicator LEDs or status displays in industrial HMIs with PWM dimming. IC Role / Device Role / Timing Role: Constant-current sink configured with emitter resistor; base driven by PWM controller. Use Value: 100 mA I_C rating and 500 mW P_C support sustained LED currents up to 80 mA with adequate thermal margin.	Use Scenario: Forming first stage of discrete instrumentation amplifier or analog comparator with matched gain. IC Role / Device Role / Timing Role: Complementary PNP half of differential pair; biased with constant current source. Use Value: Tight h_FE binning (Class B: 180–460) allows selection of closely matched units for <1% gain mismatch in precision analog front-ends.

Audio Preamp Stage

Relay Driver Circuit

Use Scenario: Amplifying weak signals from electret microphones or piezoelectric sensors before ADC sampling.

IC Role / Device Role / Timing Role: Small-signal PNP amplifier in common-emitter configuration with emitter degeneration for linearity.

Use Value: 2 dB noise figure and h_FE ≥ 120 ensure high SNR and stable gain control without added op-amp complexity.

Use Scenario: Driving 5–12 V coil relays from microcontroller GPIO pins via level-shifting interface.

IC Role / Device Role / Timing Role: Saturated PNP switch sinking relay coil current to ground when base is pulled low.

Use Value: V_CE(sat) ≤ –0.5 V minimizes power dissipation and coil voltage drop, ensuring reliable relay pull-in at low drive currents.

LED Current Sink

Differential Pair Input Stage

Use Scenario: Controlling brightness of indicator LEDs or status displays in industrial HMIs with PWM dimming.

IC Role / Device Role / Timing Role: Constant-current sink configured with emitter resistor; base driven by PWM controller.

Use Value: 100 mA I_C rating and 500 mW P_C support sustained LED currents up to 80 mA with adequate thermal margin.

Use Scenario: Forming first stage of discrete instrumentation amplifier or analog comparator with matched gain.

IC Role / Device Role / Timing Role: Complementary PNP half of differential pair; biased with constant current source.

Use Value: Tight h_FE binning (Class B: 180–460) allows selection of closely matched units for <1% gain mismatch in precision analog front-ends.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC327-40	V_CEO = –45 V, h_FE = 250–630, TO-92, same pinout	Higher breakdown voltage and narrower h_FE spread; better for higher-voltage switching	Select BC327-40 when operating above –25 V rail or requiring tighter gain consistency.
PN2907A	V_CEO = –60 V, I_C = –600 mA, TO-92, same pinout	Higher current/power rating but higher V_CE(sat) (–1.6 V typical); less suitable for low-loss switching	Choose PN2907A only when >100 mA load current is required and thermal budget permits higher saturation loss.

Compared with BC308_J35Z, BC327-40 offers improved voltage margin and gain uniformity for modern replacements, while PN2907A trades off saturation efficiency for higher current capacity - neither is pin-compatible without verification of layout clearance and thermal path adequacy.

Availability

BC308_J35Z is available at Aetrix Electronics and suitable for audio signal conditioning, electromechanical interface, and discrete analog circuitry requiring stable component supply, long-lifecycle availability, and legacy TO-92 form factor compatibility.

Supply support for BC308_J35Z includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The BC308_J35Z belongs to Fairchild's legacy BC307/308/309 family of general-purpose PNP transistors, engineered for cost-sensitive, high-reliability linear and switching applications in consumer, industrial, and automotive electronics.

FAQ

What is the maximum collector-emitter voltage rating for BC308_J35Z?

The BC308_J35Z has a V_CEO rating of –25 V at T_A = 25°C, meaning it can safely withstand up to 25 volts between collector and emitter with the base open. Exceeding this voltage risks avalanche breakdown. This rating is confirmed in Fairchild's Rev. A2 datasheet and applies specifically to BC308 and BC309 variants - not the BC307.

Does BC308_J35Z have a specified noise figure, and under what conditions?

Yes, BC308_J35Z has a noise figure of 2 dB, measured at V_CE = –5 V, I_C = –0.2 mA, R_G = 2 kΩ, and f = 1 kHz. This value is shared with BC307 and applies to low-frequency small-signal amplification; BC309 specifies different noise performance in wider bandwidths.

What is the pin configuration of BC308_J35Z in the TO-92 package?

BC308_J35Z uses the standard TO-92 pinout: Pin 1 is Collector, Pin 2 is Base, and Pin 3 is Emitter - verified from Fairchild's package diagram and consistent across BC307/308/309 series. This matches EIAJ and JEDEC TO-92 outline standards.

Can BC308_J35Z be used as a direct replacement for BC307 in existing designs?

BC308_J35Z can replace BC307 in many cases, but caution is required: BC307 has higher V_CEO (–45 V) and V_CES (–50 V) than BC308_J35Z (–25 V / –30 V). If the original design operates near BC307's voltage limits, BC308_J35Z may not be safe. Always verify operating voltage margins before substitution.

What h_FE classification does BC308_J35Z fall under, and how is it marked?

BC308_J35Z is offered in three h_FE classifications - A (120–220), B (180–460), and C (380–800) - with the gain bin indicated by a suffix letter (e.g., BC308A, BC308B). The "J35Z" suffix suggests a specific manufacturing lot and gain bin; exact classification must be confirmed via device marking or traceable test data.

BC308_J35Z Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 100 mA

Voltage - Collector Emitter Breakdown (Max):: 25 V

Vce Saturation (Max) @ Ib, Ic:: 500mV @ 5mA, 100mA

Current - Collector Cutoff (Max):: 15nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 120 @ 2mA, 5V

Power - Max:: 500 mW

Frequency - Transition:: 130MHz

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

BC308_J35Z FAQ

1.How can I place an order for BC308_J35Z through Aetrix?

Please submit a Request for Quotation (RFQ) for BC308_J35Z on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for BC308_J35Z reliable?

The price and inventory of BC308_J35Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC308_J35Z is usually 5 days.

3.What payment methods are accepted for BC308_J35Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC308_J35Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC308_J35Z?

BC308_J35Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC308_J35Z order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for BC308_J35Z?

For technical support, including BC308_J35Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC308_J35Z requirements.

6.How does Aetrix verify that BC308_J35Z is sourced from the original manufacturer or authorized distributors?

All BC308_J35Z products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that BC308_J35Z meets industry standards.

7.What is the process for return or replacement of BC308_J35Z?

All BC308_J35Z units undergo pre-shipment inspection (PSI). If there is an issue with BC308_J35Z, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The BC308_J35Z part is unused and in its original packaging.

Return procedure for BC308_J35Z:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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