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Nexperia USA Inc. BC849CW,135
- Part No.:
- BC849CW,135
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Single Bipolar Transistors
- Package:
- SC-70, SOT-323
- Datasheet:
-
BC849CW,135.pdf
- Description:
- TRANS NPN 30V 0.1A SOT-323
- Quantity:
- Payment:
- Shipping:
Inventory:8,496
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Product details
Overview
BC849CW,135 from Nexperia is an NPN general-purpose bipolar junction transistor in SOT323 package, rated for 45 V VCEO, 100 mA IC, and featuring hFE of 420–800 at 2 mA/5 V. It serves as a low-noise amplifying or switching element in audio-frequency signal paths, particularly in compact consumer audio equipment.
For engineers reviewing the BC849CW,135 datasheet, BC849CW,135 pinout, BC849CW,135 application, or BC849CW,135 equivalent, key selection criteria include DC current gain consistency across production lots, thermal resistance (625 K/W on FR4), low noise figure (≤4 dB at 1 kHz), and compatibility with SOT323 reflow profiles in space-constrained PCB layouts.
Technical Context
This transistor operates in linear or active-switching modes with defined saturation behavior: VCE(sat) ≤ 250 mV at IC = 10 mA/IB = 0.5 mA and ≤ 600 mV at IC = 100 mA/IB = 5 mA. Its fT of 100 MHz supports stable small-signal amplification up to mid-VHF range.
Designed for ambient operation from −65 °C to +150 °C, it exhibits low leakage: ICBO ≤ 15 nA at VCB = 30 V and Tj = 25 °C, rising to ≤ 5 μA at 150 °C - critical for thermally demanding audio bias networks.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 45 V - maximum safe collector-emitter voltage under open-base condition; defines headroom for audio stage supply rails |
| IC (DC) | 100 mA - continuous collector current limit; sets upper bound for load-driving capability in preamp stages |
| hFE | 420–800 - DC current gain at 2 mA/5 V; enables predictable base drive sizing for low-power switching |
| fT | 100 MHz - transition frequency; ensures adequate bandwidth for high-fidelity audio signal amplification |
| Rth j-a | 625 K/W - thermal resistance on FR4 board; informs derating requirements above 25 °C ambient |
| F (noise) | ≤4 dB - noise figure at 1 kHz/200 μA; qualifies device for low-noise preamplifier input stages |
| Cc | ≤3 pF - collector capacitance at 10 V; minimizes Miller effect distortion in high-gain configurations |
Pinout & Package
SOT323 plastic surface-mounted package (2.2 mm × 1.35 mm × 0.95 mm max height), optimized for automated placement and IR-reflow soldering on dense PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Base | Current-controlled input node; requires series resistor to limit IB and ensure hFE-based IC regulation |
| 2 | Emiter | Reference terminal for bias network; connected to ground or emitter degeneration resistor in common-emitter amps |
| 3 | Collector | Output current sink; routed to load or next stage with minimal trace inductance to preserve fT performance |
Key Features
| Feature | Design Value |
|---|---|
| Low-noise amplification | 4 dB noise figure at 1 kHz enables use in microphone preamps and tape playback head buffers without added noise floor |
| High hFE bin (C grade) | 420–800 gain range reduces base drive current variation across production, simplifying bias design in volume-manufactured audio gear |
| SOT323 footprint | Compact 2.2 mm × 1.35 mm outline allows placement in tight spaces such as portable headphone amplifier PCBs |
| Thermal stability | 150 °C max junction temperature and controlled ICBO drift support reliable operation in enclosed consumer enclosures |
Applications
| Audio Preamplifier Stage | Tape Playback Head Buffer |
|---|---|
Use Scenario: Amplifying weak signals from moving-magnet phono cartridges or electret microphones before ADC or power amplification. IC Role / Device Role / Timing Role: NPN small-signal amplifier in common-emitter configuration with emitter degeneration. Use Value: 420–800 hFE ensures consistent gain across batches; ≤4 dB noise figure preserves signal-to-noise ratio in first amplification stage. | Use Scenario: Isolating and buffering analog audio signals from magnetic tape playback heads in portable cassette players. IC Role / Device Role / Timing Role: Low-capacitance (≤3 pF) voltage follower or gain-stage buffer to prevent head loading and high-frequency loss. Use Value: Low Cc and high fT maintain flat frequency response up to 15 kHz; SOT323 size fits miniaturized transport mechanisms. |
| Hi-Fi Tone Control Circuit | Compact Audio Mixer Input Stage |
Use Scenario: Implementing active bass/treble equalization networks in battery-powered portable speakers. IC Role / Device Role / Timing Role: Linear-mode gain block with adjustable feedback, operating at IC = 1–5 mA for low distortion. Use Value: Stable hFE and low VBE (580–700 mV) enable precise DC bias setting; 45 V VCEO accommodates dual-rail ±12 V supplies. | Use Scenario: Summing multiple line-level audio sources (e.g., Bluetooth, AUX, mic) into a single output path in smart speaker designs. IC Role / Device Role / Timing Role: Discrete summing amplifier input transistor with individual base resistors for channel isolation. Use Value: Low ICBO (≤15 nA) prevents DC offset accumulation across parallel inputs; SOT323 allows dense multi-channel layout. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN general-purpose transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BC847CW,135 | Lower VCEO (45 V → 45 V same), but hFE bin 110–800 - wider spread than BC849CW's 420–800 | Less predictable gain in fixed-bias circuits; may require recalibration of emitter resistors | Prefer when cost sensitivity outweighs gain consistency needs |
| MMBT3904LT1G | Same SOT-23 package (not SOT323); higher VCEO (60 V); hFE 100–300 - significantly lower and broader range | Requires PCB footprint redesign; unsuitable for noise-critical preamp inputs due to higher F ≈ 5 dB | Select only if board redesign is feasible and gain tolerance >200% is acceptable |
Compared with BC847CW,135 and MMBT3904LT1G, BC849CW,135 delivers tighter hFE control and lower noise - critical for uncalibrated, high-volume audio front-ends where test time and component binning must be minimized.
Availability
BC849CW,135 is available at Aetrix Electronics and suitable for audio preamplifiers, tape playback circuits, hi-fi tone control modules, and compact mixer input stages requiring stable component supply and consistent parametric performance across manufacturing lots.
Supply support for BC849CW,135 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, formed in 2017 from the former NXP Standard Products division, with focus on automotive, industrial, computing, and consumer markets.
The BC849W series belongs to Nexperia's general-purpose bipolar transistor product line, engineered specifically for low-noise, high-gain audio-frequency amplification and switching in space-constrained consumer electronics.
FAQ
Is BC849CW,135 RoHS compliant and halogen-free?
Yes. BC849CW,135 meets RoHS Directive 2011/65/EU and is halogen-free per Nexperia standard specifications. The SOT323 package uses lead-free matte tin termination and complies with JEDEC J-STD-020 moisture sensitivity level 1 (MSL1) for unlimited floor life at ≤30 °C/85% RH.
What is the maximum allowable PCB trace length from base to decoupling capacitor?
For optimal noise performance in preamp applications, keep base trace length under 3 mm and place a 100 nF ceramic capacitor within 1 mm of the base pin (Pin 1). Longer traces increase susceptibility to RF pickup and degrade the ≤4 dB noise figure, especially near switching power supplies.
Can BC849CW,135 replace BC849B in existing designs?
Yes, with verification. BC849CW offers higher hFE (420–800 vs. 200–450 for BC849BW), so base resistor values may need reduction by ~50% to maintain same IC. VCEO remains identical at 30 V for BC849BW but 45 V for BC849CW - confirm supply rail compatibility before substitution.
Does BC849CW,135 support lead-free reflow per IPC-J-STD-020?
Yes. BC849CW,135 is qualified for lead-free reflow with peak temperature up to 260 °C (per JEDEC J-STD-020D), compatible with standard SnAgCu profiles. The SOT323 package withstands three reflow cycles without parameter shift or delamination, provided board preheat and cooling rates comply with Nexperia's recommended ramp rates.
BC849CW,135 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- -
- Package/Case:
- SC-70, SOT-323
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 100 mA
- Voltage - Collector Emitter Breakdown (Max):
- 30 V
- Vce Saturation (Max) @ Ib, Ic:
- 600mV @ 5mA, 100mA
- Current - Collector Cutoff (Max):
- 15nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 420 @ 2mA, 5V
- Power - Max:
- 200 mW
- Frequency - Transition:
- 100MHz
- Operating Temperature:
- 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-323
BC849CW,135 FAQ
1.How can I place an order for BC849CW,135 through Aetrix?
Please submit a Request for Quotation (RFQ) for BC849CW,135 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 BC849CW,135 reliable?
The price and inventory of BC849CW,135 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BC849CW,135 is usually 5 days.
3.What payment methods are accepted for BC849CW,135?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BC849CW,135 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BC849CW,135?
BC849CW,135 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BC849CW,135 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 BC849CW,135?
For technical support, including BC849CW,135 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BC849CW,135 requirements.
6.How does Aetrix verify that BC849CW,135 is sourced from the original manufacturer or authorized distributors?
All BC849CW,135 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 BC849CW,135 meets industry standards.
7.What is the process for return or replacement of BC849CW,135?
All BC849CW,135 units undergo pre-shipment inspection (PSI). If there is an issue with BC849CW,135, 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 BC849CW,135 part is unused and in its original packaging.
Return procedure for BC849CW,135:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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