| Summary: | The focus of the present thesis is the circuit-level implementation of an excess
loop delay compensation scheme which optimizes excess loop delay in Analog-to-Digital Converter(ADC) by using a programmable delay block and synchronizes the
signal passing through Dynamic Element Matching block, used to mitigate mismatch
effects of multi-bit Digital-to-Analog Converter(DAC). The proposed delay block
has tuning range of T/10 to T/2 seconds, with a step size of T/30 seconds, where
T is the time period (1.25 nanoseconds) of sampling signal (800 MHz) in high IF
(200 MHz) Bandpass [sigma delta] ADC. The implementation details of the element rotation
scheme used to calibrate the multi-bit DAC static error mismatch are also presented.
Also presented is the design of high frequency highly linear Operational Transconductance
Amplifier(OTA) targeted for continuous-time filters in a high resolution
High Intermediate Frequency (200 MHz) Bandpass [sigma delta] ADC for Software Radio
applications. Proposed OTA uses super source follower input stage to enhance its
voltage-to-current conversion linearity. The design has been simulated using TSMC
0.18 μm CMOS process. The OTA has small signal transconductance of 0.9 mA/V,
IM3 below -79 dB (for 0.3 Vpp input), Signal-to-Noise Ratio of 82 dB and power
consumption of 6.8 mW, when tested in unity gain configuration.
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