Nexperia USA Inc. BC857BW/ZLX

Overview

BC857BW/ZLX from Nexperia is a PNP general-purpose bipolar junction transistor in SOT323 (SC-70) package, rated for −45 V V_CEO, −100 mA I_C, and DC current gain (h_FE) of 220–475 at V_CE = −5 V and I_C = −2 mA. It serves as a low-voltage, low-current switching or amplification element in compact consumer and industrial signal-path circuits.

For engineers reviewing the BC857BW/ZLX datasheet, BC857BW/ZLX pinout, BC857BW/ZLX application, or BC857BW/ZLX equivalent, key selection criteria include its −45 V collector-emitter breakdown voltage, 220–475 h_FE range, SOT323 thermal resistance (625 K/W), −250 to −600 mV V_CE(sat) at I_C = −100 mA, and compatibility with reflow-soldered high-density PCB layouts.

Technical Context

This PNP BJT operates in active or saturation mode for linear amplification or digital on/off control. Its base-emitter junction exhibits −600 to −750 mV V_BE(sat) at I_C = −100 mA/I_B = −5 mA, and its transition frequency f_T reaches 100 MHz at V_CE = −5 V and I_C = −10 mA - confirming suitability for audio-frequency and low-speed digital switching.

The device's thermal resistance R_th(j-a) is 625 K/W on standard FR4 PCB, and its maximum junction temperature is 150 °C. Absolute maximum ratings include −50 V V_CBO, −5 V V_EBO, and 200 mW total power dissipation at T_amb ≤ 25 °C - defining safe operating boundaries under pulsed and continuous conditions.

Key Specifications

Pinout & Package

SOT323 (SC-70) surface-mount plastic package: 1.35 mm × 1.8 mm footprint, 0.4 mm nominal thickness, optimized for automated placement and reflow soldering on high-density PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC857BW/ZLX, BC857B,115 offers identical performance with standard logistics packaging, while MMBT3906LT1G trades 5 V lower V_CEO for +100 mA I_C and demands pinout-aware layout changes - making the former ideal for direct replacement and the latter suitable only for de novo designs prioritizing current headroom.

Availability

BC857BW/ZLX is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller GPIO expansion, low-voltage sensor interfaces, and power rail sequencing switches requiring stable component supply across production lifecycles.

Supply support for BC857BW/ZLX 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 essential semiconductors for automotive, industrial, mobile, and computing markets.

The BC857BW/ZLX belongs to Nexperia's general-purpose bipolar transistor product line, engineered for cost-sensitive, space-constrained applications demanding consistent gain, low saturation voltage, and robust SMT manufacturability.

FAQ

What is the maximum safe operating voltage for BC857BW/ZLX in a common-emitter switch?

The absolute maximum collector-emitter voltage (V_CEO) is −45 V with open base, and the recommended operating limit is below −40 V to maintain reliability. Exceeding −45 V risks avalanche breakdown and permanent degradation. Designers should apply ≥20 % voltage derating in high-temperature or high-humidity environments.

How does the BW suffix affect h_FE specification compared to BC857CW?

The BW grade specifies h_FE = 220–475 at V_CE = −5 V and I_C = −2 mA, whereas CW denotes 420–800 in the same test condition. This binning enables precise base-resistor selection: BW supports conservative drive designs, while CW allows lower base current for same collector load.

Can BC857BW/ZLX be used in linear amplifier configurations?

Yes - its f_T of 100 MHz, low noise figure (2–10 dB at 1 kHz), and stable h_FE vs. temperature support Class-A and emitter-follower amplifier use up to ~20 kHz. Maintain V_CE > −5 V and I_C < −50 mA to avoid thermal runaway and ensure linearity within ±1 % distortion.

Is the SOT323 package of BC857BW/ZLX compatible with standard reflow profiles?

Yes - Nexperia qualifies BC857BW/ZLX for JEDEC J-STD-020-compliant lead-free reflow, with peak temperature up to 260 °C. The recommended footprint matches Figure 15 in the datasheet: 0.6 mm solder land width, 0.55 mm paste stencil aperture, and 1.325 mm pad center spacing for reliable tombstoning-free assembly.