Nexperia USA Inc. BC857CW/DG/B2,135

Overview

BC857CW/DG/B2,135 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 420–800 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 BC857CW/DG/B2,135 datasheet, BC857CW/DG/B2,135 pinout, BC857CW/DG/B2,135 application, or BC857CW/DG/B2,135 equivalent, key selection criteria include its high h_FE band, SOT323 footprint compatibility, −45 V breakdown rating, thermal resistance of 625 K/W, and suitability for space-constrained biasing and level-shifting functions.

Technical Context

This PNP BJT operates in active, saturation, and cutoff regions with verified V_BE(sat) ≤ −850 mV at I_C = −100 mA/I_B = −5 mA and V_CE(sat) ≤ −600 mV under identical conditions. Its f_T of 100 MHz supports audio-frequency amplification and moderate-speed digital switching.

Thermal performance is characterized with R_th(j-a) = 625 K/W on FR4 PCB (single-sided, 35 µm Cu), and absolute maximum ratings include T_j = 150 °C, V_EBO = −5 V, and P_tot = 200 mW at T_amb ≤ 25 °C - confirming suitability for thermally unmanaged, low-power surface-mount designs.

Key Specifications

Pinout & Package

SOT323 (SC-70) plastic surface-mounted package: 1.35 mm × 1.75 mm footprint, 0.95 mm height, 3-lead configuration with gull-wing leads optimized for reflow soldering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC857BW,135, BC857CW/DG/B2,135 delivers 2× higher minimum h_FE, enabling simpler bias networks; versus MMBT3906LT1G, it offers superior voltage rating and guaranteed gain consistency but requires SOT323 layout adaptation.

Availability

BC857CW/DG/B2,135 is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller GPIO expansion, audio signal amplification, and power supply enable switching requiring stable component supply and consistent high-gain performance.

Supply support for BC857CW/DG/B2,135 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.

BC857CW/DG/B2,135 belongs to Nexperia's BC856W/BC857W/BC858W family of general-purpose PNP transistors designed for compact, cost-effective switching and amplification in consumer and industrial surface-mount applications.

FAQ

What is the maximum junction temperature and how does it affect continuous operation?

The absolute maximum junction temperature (T_j) is 150 °C. At ambient temperatures above 25 °C, power dissipation must be derated linearly using R_th(j-a) = 625 K/W. For example, at 70 °C ambient, maximum allowable P_tot drops to ~110 mW to maintain T_j ≤ 150 °C - requiring attention to I_C and V_CE in sustained on-state conditions.

Is BC857CW/DG/B2,135 pin-compatible with BC847CW or other NPN complements?

No - BC857CW/DG/B2,135 is a PNP device with pinout Base–Emitter–Collector (1–2–3), whereas BC847CW is an NPN with identical SOT323 mechanical outline but reversed polarity and complementary electrical behavior. Direct substitution would invert logic states and risk circuit malfunction; board-level redesign is required for NPN/PNP interchange.

How does the 420–800 h_FE range impact circuit design margin?

This guaranteed h_FE band allows robust bias network design without test sorting: a base resistor calculated for h_FE = 420 ensures saturation even at minimum gain, while the upper limit avoids excessive base current at h_FE = 800. It eliminates need for gain binning in production and supports one-design-fits-all layouts across manufacturing lots.

Can this transistor be used in linear amplifier configurations with predictable gain?

Yes - h_FE is specified at V_CE = −5 V and I_C = −2 mA, and Fig. 10 shows stable gain across I_C = 0.1–10 mA at 25 °C. For precision linear amplification, pair with emitter degeneration resistors and operate within −10 mA ≤ I_C ≤ −50 mA where h_FE variation remains <±15%, ensuring repeatable small-signal β-based gain.