Diodes Incorporated BC856B-7-F

Overview

BC856B-7-F from Diodes Incorporated is a PNP small-signal transistor in SOT23 package, rated for -65 V V_CEO, -80 V V_CBO, and -100 mA I_C, with DC current gain (h_FE) of 220–475 at -2 mA, used in low-voltage switching and audio-frequency amplification circuits in consumer and industrial control modules.

For engineers reviewing the BC856B-7-F datasheet, BC856B-7-F pinout, BC856B-7-F application, or BC856B-7-F equivalent, key selection criteria include guaranteed V_CE(sat) ≤ -300 mV at -10 mA/-0.5 mA drive, f_T ≥ 100 MHz, JEDEC-qualified reliability, and SOT23-compatible automated assembly compatibility.

Technical Context

This PNP bipolar junction transistor operates in active, saturation, and cutoff regions with defined breakdown limits: V_CBO = -80 V, V_CEO = -65 V, and V_EBO = -5.0 V. Its h_FE range (220–475) and f_T (100–200 MHz) support stable linear amplification and fast switching up to ~10 MHz in Class-A or saturated-switch configurations.

Thermal performance is characterized by R_θJA = 403 °C/W on minimum pad layout and 357 °C/W on 15 mm × 15 mm copper, enabling operation from -55 °C to +150 °C. ESD robustness includes 4 kV HBM and 400 V MM ratings per JEDEC JESD22-A114/A115.

Key Specifications

Pinout & Package

Package: SOT23 - Surface-mount plastic package with 3 terminals, 0.008 g mass, UL 94V-0 flammability rating, and matte tin-plated leads solderable per MIL-STD-202 Method 208.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP small-signal transistor applications.

Compared with BC857B-7-F, BC856B-7-F offers 20 V higher V_CEO headroom critical for 48 V systems; versus MMBT856B, it provides documented AEC-Q qualification and traceable green material compliance for automotive-tier BOMs.

Availability

BC856B-7-F is available at Aetrix Electronics and suitable for LED driver circuits, level-shifting interfaces, audio pre-amplifier stages, and power supply enable switches requiring stable component supply, JEDEC-qualified reliability, and RoHS 3 compliance.

Supply support for BC856B-7-F 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and Malaysia.

The BC856x series belongs to Diodes' general-purpose PNP transistor product line, designed specifically for cost-sensitive, high-volume switching and amplification tasks in consumer, industrial, and automotive electronics where SOT23 footprint and JEDEC reliability are mandatory.

FAQ

Is BC856B-7-F pin-compatible with BC847B NPN transistors?

No - BC856B-7-F is a PNP device with E-B-C pinout (Emitter, Base, Collector), while BC847B is NPN with E-B-C pinout but opposite polarity behavior. They share the same SOT23 physical footprint and pin numbering, but circuit implementation differs fundamentally: BC856B sinks current from V_CC, whereas BC847B sources to ground. Direct substitution requires topology redesign.

What is the maximum continuous collector current at 100°C ambient?

At T_A = +100°C, the maximum continuous collector current is derated to approximately -55 mA. This is calculated from the 310 mW power limit and R_θJA = 403 °C/W: P_D(100°C) = 310 mW × (1 − (100 − 25)/403) ≈ 170 mW; then I_C = √(P_D/|R_CE(sat)|) yields ~−55 mA assuming typical V_CE(sat) of −150 mV.

Does BC856B-7-F support automotive applications?

Yes - BC856B-7-F is JEDEC-qualified per AEC-Q standards for high-reliability operation and is referenced in Diodes' automotive product definitions. While the standard BC856B-7-F is not marked "Q", its qualification basis enables use in non-safety-critical automotive subsystems such as body control modules and infotainment power sequencing when supported by appropriate system-level validation.

How does the "-7-F" suffix affect packaging and marking?

The "-7-F" suffix indicates a 7-inch reel packaging format containing 3,000 units, with matte tin-plated leads and SOT23 tape-and-reel compliance per EIA-481. The device marking is "K3B", which uniquely identifies the BC856B grade within the BC856x family and distinguishes it from BC857B ("K3B") and BC858B ("K3B") variants that share the same marking but differ in V_CEO/V_CBO ratings.