The Front end read out circuits are major block in the implementation of Capacitive MEMS accelerometer. Front end read-out circuits comprises of preamplifier block containing folded cascode fully differential operational amplifier which are required for the signal conditioning of the signals received from the MEMS sensors. The op-amps are prime elements in design and implementation of mixed signal integrated circuits. The high gain and low power of the designed circuits helps in the designing of high precision IC’s for numerous application. Amongst the available topologies folded cascode topology plays vital role in the design and development of low power, high gain read out circuits. This paper illustrates the design and analysis of low power, high gain fully differential Folded Cascode Operational Amplifier for front end read out circuits. The designed op-amp exhibits a power consumption or dissipation of 92.14 μW and relatively higher open loop DC gain value with a value calculated at 81.33 dB by employing folded cascode topology. The UGB and Phase Margin for the selected design are 35 MHz and 83.60 respectively. The design operates at 5V power supply with the bias current of 12.11 μA. The circuit design and simulations have been implemented using 0.18 μm CMOS technology.
This paper presents the details design and simulation of the Folded Cascode amplifier using Source-Coupled-Logic (SCL) technology node for both the P-Type Metal Oxide Semiconductor (PMOS) and N-Type Metal Oxide Semiconductor (NMOS) input. The different way to implement the circuit design for a given specification has clearly described including all the design equation has been presented. All the parameter like open loop gain, Unity Gain Bandwidth (UGB) and Phase Margin (PM) are compared for both the NMOS and PMOS input fully differential folded cascode op-amp circuit are discussed and finally we have got after performance analysis that NMOS input fully differential folded cascode op-amp is the best choice for low power high speed application like in pipeline Analog to Digital (ADC). The circuit has been simulated using cadence virtuoso tool in 0.18µm SCL technology node.
DESIGN AND ANALYSIS OF LOW VOLTAGE, LOW POWER FULLY RECYCLING FOLDED CASCODE AMPLIFIER