The TCR is not perfectly linear over wide ranges (e.g., -40°C to 125°C). Designers must implement compensation circuits, often using a combination of resistors with opposite temperature coefficients, to "flatten" the error curve. Applications and Future Outlook
Resistor-based sensors are now ubiquitous in , where they trigger refresh rate adjustments, and in IoT nodes , where power budgets are measured in microwatts. As we move toward 3nm processes and beyond, the focus is shifting toward "all-digital" temperature sensors that leverage the delay of resistive-capacitive (RC) networks, further blurring the line between analog sensing and digital processing. Resistor-based Temperature Sensors in CMOS Tech...
Resistors are notoriously sensitive to manufacturing "corners." A resistor on one wafer may have a significantly different base resistance than one on another. Consequently, resistor-based sensors typically require one- or two-point calibration to achieve high accuracy (e.g., error < ±0.5°C). The TCR is not perfectly linear over wide ranges (e
High-poly and low-poly resistors are frequently used. While they offer good linearity, their TCR can be sensitive to process variations. As we move toward 3nm processes and beyond,
Utilizing the back-end-of-line (BEOL) metal layers provides a very stable, albeit lower, TCR, making them useful for specific high-stability requirements.
High-ohmic polysilicon resistors can be fabricated in a smaller footprint than the multi-transistor arrays required for high-accuracy BJT sensing.
The fundamental principle involves measuring the voltage drop across these resistors when biased with a constant current or using them within a Wheatstone bridge configuration. Advantages over Traditional BJT Sensors