Nexperia USA Inc. BC817K-40VL

Overview

BC817K-40VL from Nexperia is an AEC-Q101 qualified NPN general-purpose transistor in SOT23 (TO-236AB) package, rated for 45 V V_CEO, 500 mA continuous collector current, and DC current gain (h_FE) of 250–600 at V_CE = 1 V, I_C = 100 mA. It serves as a robust switching and linear amplification device in automotive body electronics, industrial control interfaces, and low-power signal conditioning circuits.

For engineers reviewing the BC817K-40VL datasheet, BC817K-40VL pinout, BC817K-40VL application, or BC817K-40VL equivalent, this page delivers verified electrical parameters, thermal derating behavior, SOT23 terminal mapping, automotive qualification status, and direct alternatives with documented h_FE and power dissipation differences.

Technical Context

This discrete NPN bipolar junction transistor operates in active, saturation, and cutoff regions with defined safe operating area (SOA) up to 1 A peak pulse (t_p ≤ 1 ms). Its design supports stable DC biasing across −55 °C to +150 °C ambient, with base-emitter saturation voltage ≤ 1.2 V at I_C = 500 mA / I_B = 50 mA.

Thermal performance is characterized by R_th(j-a) values ranging from 162 K/W (4-layer PCB, 1 cm² collector pad) to 358 K/W (single-sided FR4), enabling accurate junction temperature estimation under real board-mount conditions.

Key Specifications

Pinout & Package

SOT23 (TO-236AB) plastic surface-mounted package with 3 leads, 1.3 mm profile, and standard footprint compatible with reflow and wave soldering per Nexperia's recommended land patterns.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC817K-40VL, BC817-40,115 trades automotive qualification for lower cost and smaller thermal footprint, while MMBT3904LT1G offers broader distributor availability but sacrifices voltage margin, gain consistency, and thermal capability-making BC817K-40VL the sole option meeting full AEC-Q101 and 45 V SOA requirements.

Availability

BC817K-40VL is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC I/O modules, and medical sensor interface designs requiring stable component supply, long-term lifecycle support, and traceable AEC-Q101 compliance.

Supply support for BC817K-40VL 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, with leadership in logic, discretes, MOSFETs, and ESD protection devices.

The BC817K series belongs to Nexperia's AEC-Q101 qualified general-purpose transistor product line, engineered specifically for automotive and industrial applications demanding robustness, thermal stability, and consistent DC gain across temperature extremes.

FAQ

What is the maximum allowable junction temperature for BC817K-40VL?

The absolute maximum junction temperature (T_j) is 150 °C, as specified in the limiting values table. Operation above this threshold risks permanent degradation of h_FE and increased leakage currents. Thermal design must ensure T_j remains below 150 °C under worst-case ambient and power dissipation conditions, using the appropriate R_th(j-a) value for the actual PCB construction.

Is BC817K-40VL pin-compatible with BC847 or MMBT3904?

Yes, BC817K-40VL uses the standard SOT23 pinout (1 = Base, 2 = Emitter, 3 = Collector), matching BC847 and MMBT3904. However, it is not functionally interchangeable due to higher V_CEO (45 V vs. 45 V for BC847, 40 V for MMBT3904), higher I_C rating (500 mA vs. 100 mA), and AEC-Q101 qualification-requiring validation of gain, saturation voltage, and thermal behavior in the target circuit.

Does BC817K-40VL require a heatsink in typical applications?

No external heatsink is required. With P_tot = 775 mW on a 4-layer FR4 PCB and R_th(j-a) = 162 K/W, junction-to-ambient rise is ~125 K at full power-leaving ~25 K margin below 150 °C T_j at 25 °C ambient. Adequate copper pour on the collector pad (1 cm²) is sufficient for thermal management in most automotive and industrial implementations.

Can BC817K-40VL be used in linear amplifier configurations?

Yes, it is suitable for low-frequency linear amplification (e.g., sensor signal conditioning up to 10 kHz) due to its f_T = 100 MHz, low collector capacitance (3 pF), and stable h_FE across temperature. Designers must ensure operation within the SOA curve, limit power dissipation with proper biasing, and avoid second breakdown by respecting V_CE and I_C limits simultaneously.