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

Nexperia USA Inc. BC859CW/ZLX

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

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Part No.:: BC859CW/ZLX

Manufacturer:: Nexperia USA Inc.

Category:: Single Bipolar Transistors

Package:: SC-70, SOT-323

Datasheet:: BC859CW/ZLX.pdf

Description:: TRANS SOT323

Quantity:: RFQ Add To RFQ list

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Inventory:4,833

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Product details

Overview

BC859CW/ZLX 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, used in low-noise audio preamplifier stages and signal switching circuits.

For engineers reviewing the BC859CW/ZLX datasheet, BC859CW/ZLX pinout, BC859CW/ZLX application, or BC859CW/ZLX equivalent, key selection criteria include its PNP polarity, SOT323 footprint compatibility, low-noise figure (4 dB at 1 kHz), V_CEsat ≤ −300 mV at −10 mA/−0.5 mA, and thermal resistance of 625 K/W on FR4 PCB.

Technical Context

This device operates as a medium-gain, low-voltage PNP BJT optimized for linear amplification and switching in ambient temperatures up to +150 °C. Its h_FE range (420–800) and low f_T (100 MHz) support stable audio-frequency gain without RF instability.

Designed for surface-mount assembly on standard FR4 boards, it features low C_c (5 pF) and C_e (10 pF), enabling predictable frequency response in high-impedance node applications such as tape recorder input buffers and hi-fi preamp stages.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−45 V: Maximum safe collector-emitter voltage under open-base condition; defines usable supply headroom in PNP emitter-follower or common-emitter stages.
I_C (DC)	−100 mA: Continuous collector current rating; sets upper limit for biasing and load-driving capability in linear or switching operation.
h_FE	420–800 @ I_C = −2 mA, V_CE = −5 V: Confirmed DC current gain range; enables precise bias network design for stable quiescent point in amplifier circuits.
V_CEsat	≤ −300 mV @ I_C = −10 mA, I_B = −0.5 mA: Low saturation voltage ensures minimal power loss and voltage drop in active-low switch configurations.
f_T	100 MHz: Transition frequency confirms usable bandwidth up to ~10 MHz for small-signal amplification with adequate gain margin.
F (Noise Figure)	4 dB @ I_C = −200 μA, V_CE = −5 V, RS = 2 kΩ, 1 kHz: Verified low-noise performance suitable for microphone preamp and line-level signal conditioning.

Pinout & Package

SOT323 plastic surface-mount package (3 leads), dimensions per JEDEC SC-70: 2.2 mm × 1.35 mm × 0.95 mm max height, 0.65 mm lead pitch, FR4-compatible thermal profile.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control terminal for forward-biased PNP operation; requires negative base current relative to emitter to turn on.
2	Emiter	Current source terminal in PNP configuration; connected to higher potential rail in typical common-emitter amplifier layouts.
3	Collector	Current sink terminal; tied to load or next stage input; reverse-biased during active amplification.

Key Features

Feature	Design Value
Low-noise audio grade	4 dB noise figure at 1 kHz enables use in sensitive analog front-ends without added noise degradation.
High h_FE bin (C grade)	420–800 gain range supports tighter bias control and reduced base drive requirements vs. B-grade (220–475).
SOT323 footprint	Standardized 3-pin SC-70 package allows drop-in replacement with BC849W/BC850W (NPN complements) on same PCB layout.
Thermal robustness	150 °C max junction temperature and 625 K/W R_{th j-a} enable reliable operation in compact, unventilated enclosures.

Applications

Tape Recorder Input Stage

Hi-Fi Preamplifier

Use Scenario: Amplifying low-level magnetic tape playback signals before equalization and further processing.

IC Role / Device Role / Timing Role: PNP BJT configured as common-emitter preamplifier with emitter degeneration for linearity.

Use Value: 4 dB noise figure preserves signal-to-noise ratio; 420–800 h_FE allows stable DC bias across unit-to-unit variation.

Use Scenario: First-stage gain block in stereo phono or line-level preamplifiers requiring low distortion.

IC Role / Device Role / Timing Role: Linear PNP amplifier operating in Class-A with fixed emitter current and resistive collector load.

Use Value: Low V_CEsat (≤ −300 mV) minimizes voltage headroom loss; C_c = 5 pF avoids high-frequency peaking in feedback networks.

Audio Signal Switching

Low-Voltage Logic Interface

Use Scenario: Selecting between multiple analog audio sources using emitter-follower switching topology.

IC Role / Device Role / Timing Role: PNP switch controlling signal path conduction via base voltage control relative to emitter rail.

Use Value: −45 V V_CEO supports ±15 V or ±12 V analog rails; fast f_T ensures clean edge response up to ~10 MHz.

Use Scenario: Level-shifting TTL/CMOS logic outputs to drive PNP-based load switches or indicator drivers.

IC Role / Device Role / Timing Role: Active-low interface transistor translating 3.3 V/5 V logic HIGH into grounded base control signal.

Use Value: −100 mA I_C rating handles LED or relay coil loads; −300 mV V_CEsat ensures minimal voltage drop in saturated switching.

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 (220–475), same V_CEO (−45 V), identical SOT323 package	Reduced gain stability in precision bias networks; acceptable where lower gain suffices	Select when cost sensitivity outweighs need for tight h_FE tolerance or higher gain margin
MMBT3906	Same h_FE range (40–400 at −10 mA), −40 V V_CEO, SOT23 package (larger footprint)	Requires PCB layout change; slightly lower voltage rating limits use in ±24 V systems	Choose only if SOT23 is already standardized in design and −40 V rating meets system margin

Compared with BC859CW/ZLX, BC857BW offers cost advantage but less gain consistency, while MMBT3906 provides broader industry availability at the expense of package compatibility and reduced voltage headroom.

Availability

BC859CW/ZLX is available at Aetrix Electronics and suitable for tape recorder input stages, hi-fi preamplifiers, and low-voltage logic interfaces requiring stable component supply, consistent h_FE binning, and SOT323 footprint compatibility.

Supply support for BC859CW/ZLX 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 discrete semiconductors, formed in 2017 from the former NXP Standard Products division, specializing in high-volume, automotive-qualified, and industrial-grade components.

The BC859CW/ZLX belongs to Nexperia's general-purpose bipolar transistor product line, engineered for reliability and consistency in consumer audio, industrial signal conditioning, and interface circuitry.

FAQ

What is the maximum continuous collector current for BC859CW/ZLX?

The BC859CW/ZLX has a maximum continuous collector current (I_C) of −100 mA at T_amb ≤ 25 °C, derating linearly above that ambient temperature based on its 625 K/W thermal resistance. This rating applies under DC conditions with proper PCB copper area for heat dissipation.

Is BC859CW/ZLX pin-compatible with BC849W?

Yes - BC859CW/ZLX (PNP) and BC849W (NPN) share identical SOT323 pinout: Pin 1 = Base, Pin 2 = Emitter, Pin 3 = Collector. Their complementary polarity and matching package allow symmetrical design of push-pull or differential pairs without layout changes.

Does BC859CW/ZLX meet automotive qualification standards?

No - BC859CW/ZLX is specified for commercial and industrial applications per its data sheet; it is not AEC-Q101 qualified. For automotive use, Nexperia offers AEC-Q101 variants such as the BC859BQ series, which undergo extended stress testing and lot traceability.

What is the typical noise figure at 10 Hz to 15.7 kHz?

The BC859CW/ZLX exhibits a noise figure of 4 dB when measured at I_C = −200 μA, V_CE = −5 V, R_S = 2 kΩ, across the 10 Hz to 15.7 kHz band - matching the audio spectrum of analog tape playback systems and confirming suitability for low-noise preamplification.

BC859CW/ZLX 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/ZLX FAQ

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

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

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

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

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

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC859CW/ZLX?

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

Once your BC859CW/ZLX 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/ZLX?

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

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

All BC859CW/ZLX 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/ZLX meets industry standards.

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

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

Return procedure for BC859CW/ZLX:

1.Submit a request within 90 days.

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

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