Infineon Technologies BC 850B B5003

Overview

BC850B from Nexperia is an NPN silicon general-purpose bipolar junction transistor (BJT) designed for audio-frequency input stages and driver applications. It features a minimum DC current gain (h_FE) of 200 at I_C = 2 mA, V_CE = 5 V; V_CEO = 45 V; V_CE(sat) ≤ 250 mV at I_C = 100 mA, I_B = 5 mA; and low noise (F = 1.2 dB typ. at 1 kHz) - enabling high-fidelity signal amplification in compact analog front-ends.

For engineers reviewing the BC850B datasheet, BC850B pinout, BC850B application, or BC850B equivalent, key selection considerations include its AEC-Q101 qualification for automotive use, SOT23 package compatibility with high-density PCB layouts, RoHS-compliant Pb-free construction, and verified performance in low-voltage, low-noise AF amplifier stages.

Technical Context

The BC850B operates as a medium-voltage, medium-current NPN BJT optimized for linear amplification rather than switching. Its h_FE grouping (B-grade: 200–450 at I_C = 2 mA) ensures predictable gain stability across production lots, while its f_T = 250 MHz (typ.) supports wideband AF response up to 15 kHz with minimal phase distortion.

Thermal design is constrained by R_thJS ≤ 240 K/W (SOT23), requiring careful board-level thermal management above 100 mA continuous current. The device's low V_BE(sat) (700–900 mV) and V_CE(sat) (≤250 mV) reduce base drive power loss and improve efficiency in Class-A driver configurations.

Key Specifications

Pinout & Package

BC850B is housed in a standard SOT23 plastic surface-mount package (JEDEC TO-236AB), measuring 2.9 × 1.3 × 1.0 mm, with gull-wing leads suitable for reflow soldering 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 BC847B and MMBT3904, BC850B delivers superior thermal capability (330 mW), tighter h_FE distribution at operational current (2 mA), and best-in-class noise performance - making it the preferred choice for precision AF amplification and automotive sensor interfaces where reliability and signal fidelity are critical.

Availability

BC850B is available at Aetrix Electronics and suitable for audio preamplifiers, automotive sensor interfaces, and low-voltage driver circuits requiring stable component supply, consistent parametric performance, and long-term lifecycle support.

Supply support for BC850B 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 semiconductor expert focused on essential semiconductors, delivering high-performance, reliable components for automotive, industrial, and consumer markets.

The BC846–BC850 series belongs to Nexperia's general-purpose BJT portfolio, engineered specifically for audio-frequency linear amplification and driver functions where low noise, high gain consistency, and AEC-Q101 reliability are mandatory.

FAQ

Is BC850B pin-compatible with BC847B and BC848B?

Yes - all three share identical SOT23 pinout (1=Base, 2=Emitter, 3=Collector) and mechanical footprint. However, BC850B offers higher P_tot (330 mW vs. 250 mW) and guaranteed h_FE ≥200 at I_C = 2 mA, whereas BC847B specifies h_FE at I_C = 10 µA. Electrical substitution requires verification of thermal and gain requirements.

What is the maximum safe operating temperature for BC850B in continuous operation?

The BC850B has a maximum junction temperature (T_j) of 150 °C and a storage temperature range of –65 °C to +150 °C. For continuous operation at full rated current (100 mA), board-level thermal design must maintain solder-point temperature (T_S) ≤71 °C to sustain 330 mW dissipation without derating, per Nexperia's thermal characterization.

Does BC850B support lead-free reflow soldering?

Yes - BC850B is Pb-free and RoHS compliant, qualified for standard lead-free reflow profiles with peak temperature up to 260 °C (per JEDEC J-STD-020). The SOT23 package withstands three reflow cycles without degradation, and no special handling or moisture sensitivity level (MSL) precautions are required beyond standard dry-pack storage.

Can BC850B be used in switching applications?

While BC850B is optimized for linear AF amplification, it can operate in switching mode with t_on/t_off < 100 ns at I_C ≤ 50 mA. However, its relatively high V_CE(sat) (250 mV) and lack of specified switching parameters make dedicated switching transistors (e.g., BC817) more appropriate for high-efficiency digital or PWM applications.