Nexperia USA Inc. BC857CQBZ

Overview

BC857CQB from Nexperia is a PNP general-purpose transistor in a DFN1110D-3 (SOT8015) leadless SMD package with side-wettable flanks, rated for −45 V V_CEO, −100 mA I_C, and DC current gain (h_FE) of 420–800 at V_CE = −5 V and I_C = −2 mA. It serves as a compact, AEC-Q101-qualified switching or amplification device in space-constrained automotive and industrial control circuits.

For engineers reviewing the BC857CQB datasheet, BC857CQB pinout, BC857CQB application, or BC857CQB equivalent, key selection criteria include its ultra-small 1.1 mm × 1.0 mm footprint, low 0.48 mm profile, −650 mV V_CE(sat) at I_C = −100 mA/I_B = −5 mA, AEC-Q101 qualification, and side-wettable flank design for AOI-compatible solder joint inspection.

Technical Context

This PNP bipolar junction transistor operates with open-base collector-emitter breakdown voltage of −45 V and emitter-base breakdown voltage of −6 V, supporting reliable switching in low-voltage bias networks. Its thermal resistance R_th(j-a) is 298 K/W on 70 µm FR4 PCB, enabling stable operation up to 150 °C junction temperature.

The device delivers h_FE ≥ 420 under standard test conditions (V_CE = −5 V, I_C = −2 mA), with V_BE(sat) ≤ −850 mV at I_C = −100 mA/I_B = −5 mA and transition frequency f_T ≥ 100 MHz at V_CE = −5 V/I_C = −10 mA/100 MHz - confirming suitability for medium-speed digital switching and analog amplification.

Key Specifications

Pinout & Package

DFN1110D-3 (SOT8015) is an ultra-thin, leadless plastic package with side-wettable flanks, measuring 1.1 mm × 1.0 mm × 0.48 mm, optimized for high-density PCB layouts and AOI-compatible reflow assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC857BW,115, BC857CQB offers 55% smaller area and AOI capability; versus MMBT3906LT1G, it delivers 2.8× higher minimum h_FE, −45 V rating, and formal automotive qualification - making it superior for space-limited, high-reliability designs.

Availability

BC857CQB is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor interfaces, portable medical devices, and smart home actuator control requiring stable component supply and long-term manufacturability.

Supply support for BC857CQB 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 efficiency technologies, delivering high-performance, high-reliability discrete, logic, and MOSFET solutions for automotive, industrial, and mobile markets.

The BC857xQB series belongs to Nexperia's AEC-Q101-qualified general-purpose transistor portfolio, engineered specifically for space-constrained, high-volume automotive and industrial applications demanding AOI-compatible packaging and robust parametric stability.

FAQ

Is BC857CQB pin-compatible with BC847CQB?

No. BC857CQB is a PNP transistor while BC847CQB is its NPN complement; both share identical DFN1110D-3 (SOT8015) package and pinout (1=B, 2=E, 3=C), but polarity reversal means direct substitution would invert circuit function. Use only as functional replacement after verifying bias network compatibility.

What is the maximum allowable PCB copper thickness for thermal derating compliance?

BC857CQB's 420 mW maximum power dissipation rating assumes mounting on FR4 PCB with 70 µm copper thickness and standard footprint. Using thinner copper (e.g., 35 µm) reduces P_tot to 340 mW; thicker copper or thermal vias may improve performance but are not characterized in the official datasheet.

Does BC857CQB support reflow soldering per JEDEC J-STD-020?

Yes. The DFN1110D-3 package is qualified for standard Pb-free reflow per JEDEC J-STD-020D. Recommended peak temperature is 260 °C, with 20–40 sec duration above 217 °C. Footprint dimensions and stencil recommendations (0.1 mm thickness) are provided in Figure 17 of the datasheet.

How does h_FE variation affect base resistor selection in switching applications?

With h_FE spanning 420–800, base resistors must ensure saturation even at minimum gain. For I_C = −100 mA, using h_FE(min) = 420 yields required I_B ≥ −238 µA; applying 5× overdrive (−1.2 mA) guarantees hard saturation and immunity to process/temp drift across the full operating range.