A new 8-fold CMOS current-mode sawtooth folding amplifier

This paper presents a new 8-fold current-mode sawtooth folding amplifier. In the proposed circuit the number of current mirrors in the signal path between the input and the output is minimised. This results in minimising the delay in the signal path of the 8-fold current-mode sawtooth folding amplifier. Thus, the speed of the proposed amplifier is improved while enjoying a compact design and consuming less DC power. The functionality of the proposed circuit was tested and confirmed using LFoundry 150 nm process in Cadence simulation tools. Simulation results show that 8.4 ns settling time for the full-scale rising edge and 3.5 ns for the full-scale falling edge can be achieved. For comparison with already existing folding amplifiers, the proposed circuit was scaled down to provide four folds. Simulation results obtained from the 4-fold amplifier show that a full-scale delay of 5.9 ns can be achieved. This is more than four times faster than already existing designs in the open literature. Furthermore, the simulation results obtained from a sinusoidal and a triangular input current confirm the workability of both the 4-fold and the 8-fold amplifiers. The simulation results also show that the circuit is temperature insensitive and is functioning as expected in the temperature range −25°C to 125°C.