Nexperia USA Inc. BC849BW,135

Overview

BC849BW,135 from Nexperia is an NPN general-purpose bipolar junction transistor in SOT323 package, rated for 30 V V_CBO, 30 V V_CEO, and 100 mA I_C, with DC current gain (h_FE) of 200–450 at I_C = 2 mA and V_CE = 5 V. It serves as a low-noise amplifying or switching element in audio-frequency signal paths.

For engineers reviewing the BC849BW,135 datasheet, BC849BW,135 pinout, BC849BW,135 application, or BC849BW,135 equivalent, this part is selected for low-voltage, low-current analog amplification where noise figure ≤4 dB, f_T ≥100 MHz, and thermal resistance of 625 K/W are critical design constraints.

Technical Context

This transistor operates in linear active mode for small-signal amplification or saturated switch mode with V_CE(sat) ≤250 mV at I_C = 10 mA / I_B = 0.5 mA. Its f_T of 100 MHz and C_c ≤3 pF support stable high-frequency response up to mid-VHF range.

Designed for FR4 PCB mounting, it delivers R_{th j-a} = 625 K/W and supports continuous operation from −65 °C to +150 °C ambient. Cut-off currents (I_CBO ≤15 nA, I_EBO ≤100 nA) ensure minimal leakage in bias-sensitive stages.

Key Specifications

Pinout & Package

SOT323 plastic surface-mounted package (2.2 mm × 1.35 mm × 0.95 mm), 3-lead, JEDEC SC-70 compliant, optimized for high-density PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC849BW,135, BC847BW,135 offers higher voltage safety margin without sacrificing noise or speed, while MMBT3904LT1G trades gain consistency and pin compatibility for broader voltage capability and lower unit cost in non-critical applications.

Availability

BC849BW,135 is available at Aetrix Electronics and suitable for audio preamplifiers, tape recorder circuits, hi-fi tuner IF stages, and portable audio bias networks requiring stable component supply and consistent h_FE binning.

Supply support for BC849BW,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, spun off from NXP's Standard Products division in 2017, serving automotive, industrial, computing, and consumer markets.

The BC849W series belongs to Nexperia's general-purpose bipolar transistor product line, engineered for reliable low-noise amplification and switching in space-constrained, cost-sensitive analog signal chains.

FAQ

Is BC849BW,135 pin-compatible with BC847BW,135?

Yes - both use identical SOT323 package and share pin 1 (base), pin 2 (emitter), pin 3 (collector) assignment. However, BC847BW has higher V_CBO (50 V vs. 30 V) and identical h_FE range, making it a direct voltage-upgraded replacement without layout change.

What is the maximum continuous collector current for BC849BW,135 at 70 °C ambient?

At T_amb = 70 °C, derating applies: P_tot drops linearly from 200 mW at 25 °C using R_{th j-a} = 625 K/W. Maximum allowable I_C is ~75 mA assuming V_CE ≈ 3 V, based on thermal limit of 150 °C junction temperature.

Does BC849BW,135 support RF amplification up to 30 MHz?

Yes - with f_T = 100 MHz and C_c ≤3 pF, it maintains usable gain up to 30 MHz in properly matched common-emitter configurations. Stability must be verified with collector/base feedback and proper grounding per Figure 2 in the datasheet.

How does the marking code "2B∗" on BC849BW,135 relate to its electrical specification?

The "2B" marking identifies the BC849BW device type and h_FE bin (200–450); the asterisk indicates manufacturing location (Hong Kong or Malaysia). Electrical specs are fully defined by the full part number and are independent of the ∗ suffix - no parameter variation is associated with the country-of-origin code.