Abstract: Thermometer circuit can be designed in BiCMOS technology to measure directly the on-chip temperature right close to other functions of an Application Specific Integrated Circuit (ASIC). This paper discusses on-chip thermometry with high temperature sensitivity. The setting of an operating point around 50 °C with no-offset is discussed allowing a multiplication of the output current times ten for a better sensitivity. An analytical model based on a proportional to temperature cell and a complementary to absolute temperature cell is discussed. Linear response in the [-150 °C: +150 °C] is illustrated. However, out from this range, deviations between analytical models and simulations based on foundry models are discussed pointing the importance of the setting point depending on the temperature range.

Keywords: On-chip thermometer, BiCMOS, ASIC, CTAT, PTAT.

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