Infineon Technologies BC857BWH6778XTSA1

Overview

BC857BWH6778XTSA1 from Nexperia is a PNP silicon small-signal transistor optimized for audio-frequency input stages and driver circuits. It delivers high DC current gain (h_FE = 220–480 at I_C = 2 mA), low V_CE(sat) (max 250 mV at I_C = 10 mA/I_B = 0.5 mA), and low noise (1 dB typical at 1 kHz, 0.2 mA). It is AEC-Q101 qualified and RoHS-compliant in SOT323 package.

For engineers reviewing the BC857BWH6778XTSA1 datasheet, BC857BWH6778XTSA1 pinout, BC857BWH6778XTSA1 application, or BC857BWH6778XTSA1 equivalent, key selection criteria include guaranteed h_FE group B performance, thermal resistance (R_thJS ≤ 90 K/W for BF variants), V_CEO = 45 V rating, and automotive-grade reliability validation.

Technical Context

This PNP transistor operates in linear and switching modes with verified DC current gain across three test conditions: h_FE ≥ 220 at I_C = 10 µA/V_CE = 5 V (group B), ≥ 250 at I_C = 2 mA/V_CE = 5 V, and ≥ 475 at I_C = 10 mA/V_CE = 5 V. Its f_T reaches 250 MHz under I_C = 20 mA/V_CE = 5 V, supporting stable AF amplification up to 15 kHz with <1 dB noise figure.

Thermal design is enabled by its SOT323 package's R_thJS ≤ 90 K/W (BF variant) and P_tot = 250 mW at T_S ≤ 128 °C. The device meets AEC-Q101 stress testing for automotive environments and features V_BRCEO = 45 V, V_BRCBO = 50 V, and V_BREBO = 5 V - enabling robust biasing in dual-rail and level-shifting topologies.

Key Specifications

Pinout & Package

BC857BWH6778XTSA1 is housed in a RoHS-compliant SOT323 plastic surface-mount package (3-pin, lead pitch 0.65 mm), optimized for high-density PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC857BW,115 and MMBT857LT1G, BC857BWH6778XTSA1 provides superior thermal derating margin (128 °C vs. 124 °C/undefined) and mandatory AEC-Q101 compliance - critical for automotive signal chain integrity and long-term field reliability.

Availability

BC857BWH6778XTSA1 is available at Aetrix Electronics and suitable for automotive infotainment preamplifiers, industrial sensor signal conditioners, and consumer audio line drivers requiring stable component supply, consistent h_FE binning, and AEC-Q101 traceability.

Supply support for BC857BWH6778XTSA1 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 high-volume, high-reliability discrete and logic devices, with leadership in automotive-qualified components and energy-efficient solutions.

BC857BWH6778XTSA1 belongs to Nexperia's BC856–BC860 family of general-purpose PNP transistors, engineered specifically for high-fidelity audio-frequency amplification and robust driver-stage operation in automotive and industrial environments.

FAQ

What is the maximum operating junction temperature for BC857BWH6778XTSA1?

The absolute maximum junction temperature is 150 °C, validated per AEC-Q101. Derated power dissipation must be applied above T_S = 128 °C, where P_tot drops linearly to zero at 150 °C. Thermal design must account for R_thJS ≤ 90 K/W and board copper area per Nexperia Application Note AN10274.

Is BC857BWH6778XTSA1 pin-compatible with BC847B NPN transistors?

Yes - both use SOT323 packages with identical pinout (Emitter-Base-Collector), enabling complementary pair implementation in Class-A amplifiers. However, electrical asymmetry (e.g., h_FE spread, V_CE(sat)) requires independent biasing; direct substitution without circuit review is not recommended.

Does BC857BWH6778XTSA1 support pulsed operation beyond its DC ratings?

Yes - pulse operation up to P_tot(max)/P_tot(DC) = 10× is permitted for t_p ≤ 100 µs and duty cycle D ≤ 2%, per Figure EHP00377. This enables short-duration peak-current handling in relay drivers and LED flash circuits without thermal runaway.

How does the AEC-Q101 qualification impact supply chain assurance for this part?

AEC-Q101 validation confirms BC857BWH6778XTSA1 has passed accelerated stress tests including HTOL, TC, and ESD - ensuring consistent performance over 15+ years in automotive applications. Aetrix guarantees full traceability to wafer lot and final test data, with no last-time-buy notices issued through 2028.