Infineon Technologies BC817K40E6433HTMA1

Overview

BC817K40E6433HTMA1 from Nexperia is an NPN silicon general-purpose audio-frequency transistor in SOT23 package, rated for 45 V V_CEO, 500 mA I_C, and minimum h_FE of 250 at 100 mA/1 V. It delivers low 0.7 V V_CE(sat) at 500 mA/50 mA drive and operates up to 150 °C junction temperature, commonly used in automotive signal switching and industrial power control stages.

For engineers reviewing the BC817K40E6433HTMA1 datasheet, BC817K40E6433HTMA1 pinout, BC817K40E6433HTMA1 application, or BC817K40E6433HTMA1 equivalent, key selection criteria include guaranteed h_FE group 40 performance, AEC-Q101 qualification, SOT23 thermal resistance ≤70 K/W, and RoHS-compliant Pb-free construction.

Technical Context

This transistor features a planar epitaxial die structure optimized for high current gain linearity across collector currents from 10 µA to 500 mA, with stable h_FE over -40 °C to 105 °C ambient. Its 170 MHz f_T supports audio-band amplification and fast-switching digital logic interfacing.

The device uses standard B-E-C pinout (Pin 1 = B, Pin 2 = E, Pin 3 = C) in JEDEC TO-236AB (SOT23) package, with thermal design validated for TS ≤ 115 °C derating and R_thJS ≤ 70 K/W under soldering-point referenced conditions.

Key Specifications

Pinout & Package

SOT23 (TO-236AB) plastic surface-mount package with gull-wing leads, 1.3 mm pitch, 2.9 mm × 1.3 mm footprint, and 1.1 mm height. Designed for reflow soldering and automated placement.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN switching transistor applications.

Compared with BC817-40,115, BC817K40E6433HTMA1 adds automotive qualification and tighter h_FE binning; versus MMBT4401LT1G, it provides 2.5× higher minimum gain and lower saturation loss at full rated current.

Availability

BC817K40E6433HTMA1 is available at Aetrix Electronics and suitable for automotive body electronics, industrial PLC output stages, and medical device motor control requiring stable component supply and long-term lifecycle assurance.

Supply support for BC817K40E6433HTMA1 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-enhancing components, with leadership in discrete devices, logic ICs, and MOSFETs for automotive, industrial, and mobile markets.

BC817K40E6433HTMA1 belongs to the BC817K/BC818K AEC-Q101-qualified general-purpose transistor family, engineered specifically for high-reliability signal switching in harsh-environment automotive and industrial control systems.

FAQ

What is the maximum allowable base current for continuous operation?

The absolute maximum rated base current is 100 mA, but for reliable long-term operation at 500 mA collector current, the recommended continuous base current is 50 mA. Exceeding this value risks thermal runaway due to increased power dissipation in the base-emitter junction, especially above 85 °C ambient. Pulse operation allows up to 200 mA peak base current with duty cycle ≤2% and pulse width <300 µs.

Is BC817K40E6433HTMA1 suitable for linear amplifier applications?

While BC817K40E6433HTMA1 exhibits usable f_T (170 MHz) and moderate linearity, it is optimized for switching-not analog amplification. Its h_FE variation with collector current and temperature makes it unsuitable for precision linear gain stages. For audio preamplifiers or active filters, purpose-built low-noise transistors like BC549C or MMBT3904 are preferred.

How does the SOT23 package affect thermal performance in PCB layout?

The SOT23 package relies heavily on PCB copper area for heat dissipation. With ≥100 mm² of 1 oz copper connected to the collector pad, R_thJA improves from ~300 K/W (no copper) to ~120 K/W. The datasheet specifies R_thJS ≤70 K/W to soldering point-so thermal vias under the collector pad and internal ground/power planes are essential for sustained 500 mA operation at elevated ambient temperatures.

Can BC817K40E6433HTMA1 replace BC817-40 in existing designs?

Yes, BC817K40E6433HTMA1 is a direct functional and mechanical replacement for BC817-40 in SOT23 layouts, sharing identical pinout, electrical ratings, and footprint. The "K" suffix denotes AEC-Q101 qualification and enhanced process control-no layout or schematic changes are needed, though qualification documentation must be updated for automotive programs.