Patrick Torta

A 3-mW 74-dB SNR 2-MHz continuous-time delta-sigma ADC with a tracking ADC quantizer in 0.13-/spl mu/m CMOS

A third-order continuous-time multibit (4 bit) /spl Delta//spl Sigma/ ADC for wireless applications is implemented in a 0.13-/spl mu/m CMOS process. It is shown that the power consumption can be considerably reduced by using a tracking ADC composed of three comparators with interpolation instead of using a 4-bit flash quantizer. Moreover, the usage of a tracking ADC opens the door to a new forward-looking dynamic element matching (DEM) technique, which helps to reduce the loop delay time and consequently improves the loop stability. The SNR is 74 dB over a bandwidth of 2 MHz. The ADC consumes 3 mW from a 1.5-V supply when clocked at 104 MHz. The active area is 0.3 mm/sup 2/.

A 2.2mW, Continuous-Time Sigma-Delta ADC for Voice Coding with 95dB Dynamic Range in a 65nm CMOS Process

A second order continuous time multibit (4bit) DeltaSigma-ADC for voice coding is implemented in a 65nm CMOS process. The dynamic range (DR) is 95dB over the voice bandwidth of 20-20 000Hz. Furthermore, by using a feed back architecture the need of an anti aliasing filter is eliminated. The input operational amplifier is chopped to eliminate flicker noise and offset. These improvements give way to a substantial simplification of the analog front end by allowing the absorption of the pre-amplifier and the antialiasing filter into the DeltaSigma-ADC. Thanks to the feedback structure the slew rate at the quantizer is limited and a power-efficient tracking ADC can be used. The total harmonic distortion (THD) is below -77dB at maximum input signal of 1.4Vpp. The ADC consumes 2.2mW from a 1.2V supply when clocked at 12MHz. The active area is 0.149 mm2

A system containing an ambient light and a proximity sensor with intrinsic ambient light rejection

A system for measuring ambient light as well as proximity of a reflective object is presented. A new technique of ambient light disturbance cancellation in proximity mode is proposed, enabling high accuracy measurements over a wide range of backlight. The chip, built in a 0.25μm CMOS technology, is capable of measuring ambient light intensities with a resolution better than 0.25lx at a 16klx full-scale and a reflected proximity IR signal with amplitude down to 200pA, rejecting backlight variations from 0 to 100μA.