An Accurate dB-Linear Programmable-Gain Amplifier with Temperature-Robust Characteristic

This paper presents an accurate dB-linear programmable-gain amplifier with temperature-robust characteristic. A novel Gm-cell feedback topology is proposed to provide linear gain control as well as bandwidth extension without any extra power consumption. Moreover, a PTAT bias is employed to further promote the temperature robustness while AC coupling stages are embedded in the adjacent stages for DC-offset cancellation. Implemented in TSMC 65-nm CMOS technology, the proposed PGA exhibits a programmable gain range of 0 dB to 42 dB with 1 dB per step and 0.17 dB error. The gain variation across −40∼125 °C is lower than 0.3 dB at all gain settings. The core circuit consumes a DC power of 3.8mV from a 1.2 V supply and occupies a layout area of 0.048 mm 2 .