This paper presents a circuit technique that enables a selective amplification of the temperature coefficient of the sensing source, thereby mitigating the need for power-intensive readout schemes and simplifying the overall sensor architecture. Temperature coefficient amplifier introduces a negative proportional-to-absolute-temperature (PTAT) voltage, enabling an amplified gradient for both PTAT and complementary-to-absolute-temperature (CTAT) voltages within the usable temperature range, resulting in a reduced burden and precise temperature measurements with a low-complexity readout circuit. With a SAR-based conversion, implemented temperature sensor in 180 nm CMOS achieves a figure-of-merit of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$41 \text{fJ} \cdot \mathrm{K}^{2}$</tex> with a 22.2 mK resolution across <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-20^{\circ} \mathrm{C}$</tex> to 100° C while consuming 20.8nW. It shows a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{3} \boldsymbol{\sigma}$</tex> inaccuracy of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{\pm} \mathbf{1. 4} \boldsymbol{4}^{\boldsymbol{\circ}} \mathbf{C}$</tex> after a single-point trimming procedure.