Ritu Singh - Academia.edu (original) (raw)
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Papers by Ritu Singh
A hybrid thin film/CMOS microsystem for fluorescence contact imaging is presented. The microsyste... more A hybrid thin film/CMOS microsystem for fluorescence contact imaging is presented. The microsystem integrates a high-performance optical filter and a 128times128-pixel imager fabricated in a 0.35 mum technology. The thin-film filter is fabricated and characterized prior to assembly. Its optical density (OD) is over 6.0 at the wavelength of interest. The performance of the microsystem is experimentally validated by imaging conventional Cy3 fluorophore spots using a low-cost pen-sized laser. The emission intensity as a function of fluorophore concentration is measured with the estimated sensitivity of 20 fluorophore/ mum2.
We present a capacitive digital-to-analog converter (DAC) architecture combining properties of th... more We present a capacitive digital-to-analog converter (DAC) architecture combining properties of the binary-weighted and serial charge-redistribution DACs to yield high integration density and high accuracy. The architecture provides the flexibility to trade area with conversion speed based on a set of area-speed-linearity constraints. We validate the architecture using a 10-bit two-step DAC example, simulated in a standard 0.35 m CMOS technology. The 10-bit DAC occupies 32 times less area than the conventional 10-bit binary-weighted DAC, has low INL, good matching, and high tolerance to parasitic capacitance.
IEEE Transactions on Circuits and Systems I-regular Papers, 2010
A hybrid CMOS/thin-film microsystem for fluorescence contact imaging is presented. The microsyste... more A hybrid CMOS/thin-film microsystem for fluorescence contact imaging is presented. The microsystem integrates a high-performance optical interference filter and a 128 128 pixel active pixel sensor fabricated in a standard 0.35-m CMOS technology. The thin-film filter has an optical density greater than 6.0 at the wavelength of interest, providing adequate excitation rejection to the 532-nm solid-state laser. Microsystem performance is experimentally validated by imaging spots of Cyanine-3 fluorophore, conventionally used in DNA detection. The emission intensity as a function of fluorophore concentration is measured with an estimated sensitivity of 5000 fluorophore m 2 . A human DNA microarray has been imaged with the sensor prototype.
Adsorption Science & Technology, 2004
ABSTRACT: Laboratory studies were conducted to determine the adsorption and movement of cypermeth... more ABSTRACT: Laboratory studies were conducted to determine the adsorption and movement of cypermethrin on surfactant-free (natural) and surfactant-amended soils at different micelle concentrations (below the CMC, at the CMC and above the CMC) using batch equilibrium ...
A hybrid thin film/CMOS microsystem for fluorescence contact imaging is presented. The microsyste... more A hybrid thin film/CMOS microsystem for fluorescence contact imaging is presented. The microsystem integrates a high-performance optical filter and a 128times128-pixel imager fabricated in a 0.35 mum technology. The thin-film filter is fabricated and characterized prior to assembly. Its optical density (OD) is over 6.0 at the wavelength of interest. The performance of the microsystem is experimentally validated by imaging conventional Cy3 fluorophore spots using a low-cost pen-sized laser. The emission intensity as a function of fluorophore concentration is measured with the estimated sensitivity of 20 fluorophore/ mum2.
We present a capacitive digital-to-analog converter (DAC) architecture combining properties of th... more We present a capacitive digital-to-analog converter (DAC) architecture combining properties of the binary-weighted and serial charge-redistribution DACs to yield high integration density and high accuracy. The architecture provides the flexibility to trade area with conversion speed based on a set of area-speed-linearity constraints. We validate the architecture using a 10-bit two-step DAC example, simulated in a standard 0.35 m CMOS technology. The 10-bit DAC occupies 32 times less area than the conventional 10-bit binary-weighted DAC, has low INL, good matching, and high tolerance to parasitic capacitance.
IEEE Transactions on Circuits and Systems I-regular Papers, 2010
A hybrid CMOS/thin-film microsystem for fluorescence contact imaging is presented. The microsyste... more A hybrid CMOS/thin-film microsystem for fluorescence contact imaging is presented. The microsystem integrates a high-performance optical interference filter and a 128 128 pixel active pixel sensor fabricated in a standard 0.35-m CMOS technology. The thin-film filter has an optical density greater than 6.0 at the wavelength of interest, providing adequate excitation rejection to the 532-nm solid-state laser. Microsystem performance is experimentally validated by imaging spots of Cyanine-3 fluorophore, conventionally used in DNA detection. The emission intensity as a function of fluorophore concentration is measured with an estimated sensitivity of 5000 fluorophore m 2 . A human DNA microarray has been imaged with the sensor prototype.
Adsorption Science & Technology, 2004
ABSTRACT: Laboratory studies were conducted to determine the adsorption and movement of cypermeth... more ABSTRACT: Laboratory studies were conducted to determine the adsorption and movement of cypermethrin on surfactant-free (natural) and surfactant-amended soils at different micelle concentrations (below the CMC, at the CMC and above the CMC) using batch equilibrium ...