Linear programmable gain amplifier using reconfiguration local-feedback transconductors

This paper proposes a linear PGA (programmable gain amplifier) using reconfiguration local-feedback transconductors for a FPW (flexural plate-wave) allergy biosensor. By using the LFT (local-feedback transconductors), the transconductance of the proposed PGA is linear against the input voltage. By using the proposed reconfiguration methods, the transconductance behaves as the pseudo-exponential approximation function of the digital control bits. Thus, the gain error of the linear PGA is simulated to be 0.25 LSB with dynamic gain range of 45.13 dB (-24.17~20.96 dB). The proposed linear PGA is implemented by using a typical 0.18 μm CMOS process. The power consumption is 9.59 mW for 20 pF capacitive load at 20 MHz. The core area of the proposed design is 0.838×0.838 mm².