TDK Corporation presents the new L860 NTC thermistor chip which can be directly embedded into power modules and used within sintering and AI-heavy wire bonding. Its characteristics correspond to the common MELF-R/T curve with R100 of 493 Ω. The lead-free chip with ordering code B57860L0522J500 is designed for a wide temperature range of -55 °C to +175 °C, has dimensions of 1.6 x 1.6 x 0.5 mm.
Unlike conventional SMD NTC chips, the leadless NTC chip is mounted horizontally. For electrical bonding, the product is fitted on the bottom with a Ni/Ag thin-film electrode for sintering on the DCB (direct copper bonded) board of power modules, while the upper electrode comprises a Ni/Au thin-film electrode for aluminum wire bonding. Soldering processes are not necessary.
In contrast to other technologies, this solution establishes an outstanding thermal coupling of NTC chips to power modules, which, in turn, causes a very short response time and high-precision temperature measurement and control. The efficiency of power modules is typically highest when operating close to their power limits, however, to operate at these limits, precise temperature control is essential. Typical operating temperatures are in the range of 100 °C, but may slightly increase to 175 °C.
The L860 is suitable for integration into IGBT and IPM modules.