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

Nexperia USA Inc. BC859CW/ZLF

Name: BC859CW/ZLF
Brand: Nexperia USA Inc.
SKU: BC859CW/ZLF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC859CW/ZLF

Manufacturer:: Nexperia USA Inc.

Category:: Single Bipolar Transistors

Package:: SC-70, SOT-323

Datasheet:: BC859CW/ZLF.pdf

Description:: TRANS SOT323

Quantity:: RFQ Add To RFQ list

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Inventory:7,276

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Product details

Overview

BC859CW/ZLF from Nexperia is a PNP general-purpose bipolar junction transistor in SOT323 package, rated for −45 V V_CEO, −100 mA I_C, and 200 mW P_tot, with h_FE of 420–800 at I_C = −2 mA. It serves as an audio-frequency amplification and switching device in low-noise preamplifier stages of hi-fi equipment and tape recorders.

For engineers reviewing the BC859CW/ZLF datasheet, BC859CW/ZLF pinout, BC859CW/ZLF application, or BC859CW/ZLF equivalent, key selection criteria include its guaranteed h_FE range, low noise figure (4 dB at 1 kHz), V_CEsat ≤ −300 mV at I_C = −10 mA/I_B = −0.5 mA, and SOT323 thermal resistance of 625 K/W on FR4 PCB.

Technical Context

This PNP BJT operates in linear amplification and saturated switching modes, with base-emitter turn-on voltage of 600–750 mV at I_C = −2 mA and transition frequency f_T ≥ 100 MHz. Its low collector capacitance (C_c ≤ 5 pF) and emitter capacitance (C_e ≈ 10 pF) support stable high-frequency gain up to audio band.

The device features tight h_FE binning (420–800) and low leakage: ICBO ≤ −15 nA at V_CB = −30 V, T_j = 25 °C, and IEBO ≤ −100 nA at V_EB = −5 V - enabling predictable bias stability in discrete amplifier topologies.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−45 V: Maximum safe collector-emitter voltage before breakdown in open-base configuration.
I_C (DC)	−100 mA: Continuous collector current limit defining usable linear/saturation operating range.
h_FE	420–800 at I_C = −2 mA, V_CE = −5 V: Guaranteed DC current gain for stable bias design in low-noise amplifiers.
V_CEsat	≤ −300 mV at I_C = −10 mA/I_B = −0.5 mA: Low saturation voltage enables efficient switching with minimal power loss.
f_T	≥ 100 MHz: Transition frequency confirming usable gain up to mid-VHF, supporting wideband audio and RF coupling.
Noise Figure	4 dB at 1 kHz, 200 μA I_C, R_S = 2 kΩ: Quantified low-noise performance critical for microphone preamps and signal conditioning.
R_{th j-a}	625 K/W on FR4: Thermal resistance determines junction temperature rise under 200 mW dissipation at ambient.

Pinout & Package

SOT323 (SC-70) surface-mount plastic package: 1.3 mm × 1.75 mm footprint, 0.95 mm height, 3-terminal leadframe with gull-wing leads. Designed for automated placement and reflow soldering on FR4 PCBs.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Current-controlled input node; requires ~0.6–0.8 V forward bias relative to emitter for conduction.
2	Emiter	Common reference terminal in common-emitter configuration; carries total emitter current (I_C + I_B).
3	Collector	Output current sink node; reverse-biased relative to emitter during active operation; connects to load or supply rail.

Key Features

Feature	Design Value
Guaranteed h_FE range	420–800 ensures consistent DC bias point across production lots in amplifier designs.
Low V_CEsat	≤ −300 mV at moderate drive enables low-loss switching in discrete logic and power control stages.
Low noise figure	4 dB at audio frequencies supports high-fidelity signal amplification without added background hiss.
Small-outline SOT323	1.3 × 1.75 mm footprint saves board space while maintaining thermal performance via FR4 pad layout.
High f_T	≥ 100 MHz allows stable gain in wideband applications including IF amplifiers and oscillator buffers.

Applications

Audio Preamplifier Stage

Tape Recorder Signal Path

Use Scenario: First-stage amplification of low-level microphone or phono signals in portable hi-fi systems.

IC Role / Device Role / Timing Role: PNP BJT configured in common-emitter topology providing voltage gain and impedance transformation.

Use Value: 420–800 h_FE and 4 dB noise figure ensure high SNR and stable DC operating point without trimming.

Use Scenario: Bias and amplification circuitry in analog cassette playback/recording electronics.

IC Role / Device Role / Timing Role: Linear amplification element in head preamp and erase oscillator driver circuits.

Use Value: Low V_CEsat and tight h_FE binning reduce distortion and improve channel matching across dual-channel tape decks.

Discrete Logic Inverter

Low-Power Switch Driver

Use Scenario: Level-shifting and signal inversion in battery-powered embedded control panels.

IC Role / Device Role / Timing Role: Saturated-switch BJT acting as active-low inverter with pull-up resistor.

Use Value: −100 mA I_C rating and ≤ −300 mV V_CEsat enable reliable TTL/CMOS-compatible output swing at <1 mA drive.

Use Scenario: Driving small relays, LEDs, or piezo buzzers from microcontroller GPIO pins.

IC Role / Device Role / Timing Role: Current-amplifying switch interfacing low-current digital outputs to higher-power loads.

Use Value: 200 mW P_tot and 625 K/W R_{th j-a} allow continuous 100 mA switching without heatsinking on standard FR4.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC857BW	Lower h_FE range (220–475); same V_CEO (−45 V), identical SOT323 package.	Less suitable for low-noise preamp stages requiring high gain stability; acceptable for switching.	Select when cost sensitivity outweighs gain consistency requirements.
MMBT3906	Higher V_CEO (−40 V), wider h_FE spread (100–300), slightly higher V_CEsat (≤ −400 mV).	Lower gain uniformity reduces predictability in precision bias networks; widely available but less optimized for audio.	Choose for legacy compatibility or where broader h_FE tolerance is acceptable.

Compared with BC859CW/ZLF, BC857BW offers lower gain consistency but identical voltage/current ratings, while MMBT3906 trades gain precision and noise performance for broader industry availability and relaxed binning - making BC859CW/ZLF optimal for noise-critical, gain-stable audio designs.

Availability

BC859CW/ZLF is available at Aetrix Electronics and suitable for audio preamplifiers, tape recorder signal paths, discrete logic inverters, and low-power switch drivers requiring stable component supply and consistent h_FE performance.

Supply support for BC859CW/ZLF 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

Nexperia is a global leader in high-volume production of discrete semiconductors, acquired from NXP's Standard Products division in 2017, with manufacturing and R&D centers across Asia, Europe, and the Americas.

The BC859CW/ZLF belongs to Nexperia's general-purpose bipolar transistor product line, engineered specifically for cost-sensitive, high-reliability audio and switching applications where gain consistency, low noise, and SOT323 space efficiency are essential.

FAQ

Is BC859CW/ZLF RoHS compliant and halogen-free?

Yes. BC859CW/ZLF meets RoHS Directive 2011/65/EU and is halogen-free per Nexperia's standard product specifications. The "ZLF" suffix explicitly denotes compliance with both requirements, confirmed in Nexperia's official product change notices and material declarations.

What is the maximum allowable junction temperature and how is it enforced?

The absolute maximum junction temperature is 150 °C. This limit is enforced by derating total power dissipation linearly above Tamb = 25 °C using R_{th j-a} = 625 K/W. At 85 °C ambient, maximum safe P_tot drops to 120 mW to maintain T_j ≤ 150 °C.

Can BC859CW/ZLF replace BC859B in existing designs?

Yes, with verified performance improvement. BC859CW has h_FE 420–800 versus BC859B's 220–475, offering tighter gain distribution and lower noise. Electrical pinout, package, and voltage/current ratings are identical - no layout or schematic changes required.

Does BC859CW/ZLF support Pb-free reflow soldering profiles?

Yes. BC859CW/ZLF is qualified for standard Pb-free reflow per JEDEC J-STD-020, with peak temperature up to 260 °C for 30 seconds. The SOT323 package uses matte tin-plated leads compatible with both SnPb and Pb-free processes without dewetting or embrittlement.

BC859CW/ZLF Specifications

Product attributes: Attribute value

Manufacturer:: Nexperia USA Inc.

Series:: -

Package/Case:: SC-70, SOT-323

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: -

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

Voltage - Collector Emitter Breakdown (Max):: -

Vce Saturation (Max) @ Ib, Ic:: -

Current - Collector Cutoff (Max):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: -

Power - Max:: -

Frequency - Transition:: -

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323

BC859CW/ZLF FAQ

1.How can I place an order for BC859CW/ZLF through Aetrix?

Please submit a Request for Quotation (RFQ) for BC859CW/ZLF 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 BC859CW/ZLF reliable?

The price and inventory of BC859CW/ZLF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC859CW/ZLF is usually 5 days.

3.What payment methods are accepted for BC859CW/ZLF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC859CW/ZLF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC859CW/ZLF?

BC859CW/ZLF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC859CW/ZLF 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 BC859CW/ZLF?

For technical support, including BC859CW/ZLF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC859CW/ZLF requirements.

6.How does Aetrix verify that BC859CW/ZLF is sourced from the original manufacturer or authorized distributors?

All BC859CW/ZLF 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 BC859CW/ZLF meets industry standards.

7.What is the process for return or replacement of BC859CW/ZLF?

All BC859CW/ZLF units undergo pre-shipment inspection (PSI). If there is an issue with BC859CW/ZLF, 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 BC859CW/ZLF part is unused and in its original packaging.

Return procedure for BC859CW/ZLF:

1.Submit a request within 90 days.

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

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