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

Nexperia USA Inc. BC850CW/ZLF

Name: BC850CW/ZLF
Brand: Nexperia USA Inc.
SKU: BC850CW/ZLF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: BC850CW/ZLF

Manufacturer:: Nexperia USA Inc.

Category:: Single Bipolar Transistors

Package:: SC-70, SOT-323

Datasheet:: BC850CW/ZLF.pdf

Description:: TRANS SOT323

Quantity:: RFQ Add To RFQ list

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Inventory:7,062

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Product details

Overview

BC850CW/ZLF from Nexperia is an NPN general-purpose bipolar junction transistor in SOT323 package, rated for 45 V V_CEO, 100 mA I_C, and featuring h_FE of 420–800 at 2 mA/5 V; used in low-noise audio preamplifier stages and signal conditioning circuits.

For engineers reviewing the BC850CW/ZLF datasheet, BC850CW/ZLF pinout, BC850CW/ZLF application, or BC850CW/ZLF equivalent, key selection criteria include DC current gain consistency across production lots, low noise figure (≤4 dB at 1 kHz), saturation voltage under 600 mV at 100 mA, and thermal resistance (625 K/W) on FR4 PCBs.

Technical Context

This transistor operates as a linear amplifying device with fixed-polarity NPN structure, optimized for small-signal amplification where low base-emitter voltage (580–770 mV) and tight h_FE distribution (420–800) support stable biasing in discrete gain blocks. Its 3 pF collector capacitance and 100 MHz f_T enable reliable performance up to mid-audio frequencies.

Designed for surface-mount implementation on standard FR4 boards, it relies on thermal dissipation via its SOT323 footprint (R_{th j-a} = 625 K/W) and supports pulsed operation up to 200 mA I_CM with 300 μs pulse width and 2% duty cycle per IEC 134.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - maximum safe collector-emitter voltage before breakdown in common-emitter configuration
I_C (DC)	100 mA - continuous collector current rating defining linear operating envelope
h_FE	420–800 - DC current gain range at 2 mA I_C/5 V V_CE, critical for predictable bias point stability
V_CE(sat)	≤600 mV at 100 mA/5 mA - ensures low conduction loss in switching or saturated amplifier stages
f_T	100 MHz - transition frequency confirming usable bandwidth for audio and low-speed digital signal paths
F (Noise Figure)	≤4 dB at 1 kHz - quantifies added noise in low-level analog amplification, e.g., microphone preamps
R_{th j-a}	625 K/W - thermal resistance from junction to ambient on FR4, governing temperature rise under load

Pinout & Package

SOT323 plastic surface-mounted package (3 leads), dimensions: 2.2 mm × 1.35 mm × 0.95 mm max height; JEDEC MO-203AA / EIAJ SC-70 compliant; moisture sensitivity level (MSL) not specified in source data.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control terminal for carrier injection; requires current-limited drive to maintain h_FE-based amplification
2	Emitter	Current sink reference node; connected to ground or low-impedance return path in common-emitter topology
3	Collector	Output current source node; interfaces with load resistor or next-stage input impedance

Key Features

Feature	Design Value
High h_FE grade	420–800 at 2 mA/5 V enables precise DC bias design with minimal base drive current
Low noise performance	≤4 dB noise figure at 1 kHz supports high-fidelity audio front-end applications
Low V_BE	580–770 mV reduces base bias network power consumption and improves thermal stability
Small-outline SMT package	SOT323 footprint allows dense placement in space-constrained consumer audio PCBs
Robust thermal rating	150 °C max junction temperature supports operation in enclosed industrial enclosures

Applications

Audio Preamp Stage

Tape Recorder Input Amplifier

Use Scenario: Amplifying weak signals from dynamic microphones or magnetic tape heads before ADC or further processing.

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

Use Value: 420–800 h_FE ensures consistent gain across batches; ≤4 dB noise figure preserves signal-to-noise ratio.

Use Scenario: Boosting low-level playback signals from analog tape heads prior to equalization and output buffering.

IC Role / Device Role / Timing Role: Linear voltage amplifier with fixed DC bias, operating in Class-A mode.

Use Value: Low V_CE(sat) (≤600 mV) minimizes headroom loss; 100 MHz f_T covers full audio band (20 Hz–20 kHz).

Hi-Fi Tone Control Circuit

Low-Power Sensor Signal Conditioning

Use Scenario: Implementing active bass/treble adjustment networks in compact stereo receivers.

IC Role / Device Role / Timing Role: Gain-setting transistor in feedback-controlled op-amp auxiliary stages.

Use Value: Tight h_FE tolerance avoids calibration drift; SOT323 enables board area savings in multi-channel designs.

Use Scenario: Amplifying millivolt-level outputs from thermistors or piezoelectric sensors in battery-powered devices.

IC Role / Device Role / Timing Role: Discrete transimpedance or voltage-gain stage preceding MCU ADC input.

Use Value: 100 mA I_C rating supports rail-to-rail swing; low I_CBO (≤15 nA) prevents leakage-induced offset errors.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN small-signal amplification applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC849CW	Lower h_FE (200–450), same V_CEO (30 V), lower V_CEO than BC850CW	Not suitable where ≥45 V supply rails or higher gain stability required	Select when cost sensitivity outweighs gain margin needs and supply voltage stays ≤30 V
MMBT3904LT1G	Higher V_CEO (40 V), h_FE 100–300, SOT-23 package (larger footprint)	Less suitable for ultra-compact layouts; lower gain limits precision biasing	Choose when legacy SOT-23 compatibility or wider V_CEO margin is prioritized over gain and noise

Compared with BC849CW and MMBT3904LT1G, BC850CW/ZLF delivers superior h_FE consistency and lower noise-critical for high-fidelity audio-while maintaining identical SOT323 footprint and thermal behavior on FR4.

Availability

BC850CW/ZLF is available at Aetrix Electronics and suitable for audio preamplifiers, tape recorder signal chains, and hi-fi tone control circuits requiring stable component supply and batch-to-batch h_FE uniformity.

Supply support for BC850CW/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 discrete, logic, and PowerMOS semiconductors, spun off from NXP's Standard Products division in 2017, serving automotive, industrial, computing, and consumer markets.

BC850CW/ZLF belongs to Nexperia's BC849W/BC850W series of general-purpose NPN transistors, designed specifically for low-noise, low-voltage audio-frequency amplification in compact SMT form factors.

FAQ

What is the maximum operating junction temperature for BC850CW/ZLF?

The absolute maximum junction temperature (T_j) is 150 °C, as defined in the Limiting Values table. This rating assumes proper PCB thermal design-specifically mounting on FR4 with no additional heatsinking-and must not be exceeded during continuous or pulsed operation to ensure long-term reliability and parameter stability.

Is BC850CW/ZLF RoHS compliant and lead-free?

Yes, BC850CW/ZLF is RoHS compliant and lead-free. Nexperia confirms compliance with Directive 2011/65/EU (RoHS 2) and subsequent amendments. The "ZLF" suffix explicitly denotes lead-free termination finish and green molding compound, meeting JEDEC J-STD-020 moisture sensitivity requirements for reflow soldering.

Can BC850CW/ZLF replace BC850B in existing designs?

Yes, BC850CW/ZLF is a direct functional replacement for BC850B in SOT323 layout, sharing identical pinout, package dimensions, and electrical ratings. However, its h_FE range (420–800) is higher than BC850B (200–450), so verify bias network stability-especially in Class-A amplifiers-where increased gain may shift quiescent points.

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

The noise figure is specified as ≤4 dB under conditions: I_C = 200 μA, V_CE = 5 V, R_S = 2 kΩ, and bandwidth 10 Hz to 15.7 kHz. This value reflects broadband noise performance relevant to analog audio applications, including tape playback and microphone preamplification, and is measured per standard test methodology in the original NXP data sheet.

BC850CW/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

BC850CW/ZLF FAQ

1.How can I place an order for BC850CW/ZLF through Aetrix?

Please submit a Request for Quotation (RFQ) for BC850CW/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 BC850CW/ZLF reliable?

The price and inventory of BC850CW/ZLF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC850CW/ZLF is usually 5 days.

3.What payment methods are accepted for BC850CW/ZLF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC850CW/ZLF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for BC850CW/ZLF?

BC850CW/ZLF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your BC850CW/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 BC850CW/ZLF?

For technical support, including BC850CW/ZLF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC850CW/ZLF requirements.

6.How does Aetrix verify that BC850CW/ZLF is sourced from the original manufacturer or authorized distributors?

All BC850CW/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 BC850CW/ZLF meets industry standards.

7.What is the process for return or replacement of BC850CW/ZLF?

All BC850CW/ZLF units undergo pre-shipment inspection (PSI). If there is an issue with BC850CW/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 BC850CW/ZLF part is unused and in its original packaging.

Return procedure for BC850CW/ZLF:

1.Submit a request within 90 days.

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

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