A Signal- and Transient-Current Boosting Amplifier for Large Capacitive Load Applications.

A signal- and transient-current boosting (STCB) circuit is proposed and applied to a single-stage amplifier driving large capacitive loads. The proposed STCB circuit provides gain-bandwidth product (GBW) extension, slew-rate (SR) improvement and gain enhancement to the amplifier, with only slight alterations to the frequency response and transient response of the single-stage amplifier driving large capacitive loads. No on-chip capacitor or resistor is required. The STCB amplifier is fabricated in a commercial 0.18-\mum CMOS technology. The active chip area is 0.00705 mm^2. The supply is 1.8 V, and the current consumption is 20.3 \muA. The capacitive load (CO) ranges from about 4.4 nF to 19 nF. The measured results with a \sim19-nF load show the small-signal figure-of-merit (FOMS=\rm GBW\cdot CO/{\rm power}) and the large-signal figure-of-merit (FOML=\rm SR\cdot CO/{\rm power}) are 150345 MHz \cdot pF/mW and 31213 V/\mus\cdotpF/mW, respectively, which correspond to improvements of 1.52 times and 1.36 times, respectively, to the prior art. The achieved phase margin and gain margin are 80.8^\circ and 36.3 dB, respectively. [ABSTRACT FROM AUTHOR]