Abstract: Circuits and methods for reducing input dependent capacitor DAC switching current in flash-successive approximation register (SAR) analog-to-digital converters (ADCs) are disclosed. An ADC includes an M-bit flash ADC and N-bit SAR ADC. In flash conversion phase, flash ADC outputs digital signal including most significant M-bits of N-bits of digital output code for a sampled analog signal. SAR ADC includes capacitor DAC and digital engine. The capacitor DAC includes first and second set of capacitors, where first ends of the first and second set of capacitors are coupled to common terminal. The digital engine provides the N-bits of digital output code in SAR conversion phase based on the digital signal and a voltage (Vcom) at the common terminal. During flash conversion phase, second ends of the first set of capacitors are connected to Vref and Vgnd respectively so as to generate a voltage level corresponding to the digital signal as Vcom.

Abstract: Circuits and methods for reducing input dependent capacitor DAC switching current in flash-successive approximation register (SAR) analog-to-digital converters (ADCs) are disclosed. An ADC includes an M-bit flash ADC and N-bit SAR ADC. In flash conversion phase, flash ADC outputs digital signal including most significant M-bits of N-bits of digital output code for a sampled analog signal. SAR ADC includes capacitor DAC and digital engine. The capacitor DAC includes first and second set of capacitors, where first ends of the first and second set of capacitors are coupled to common terminal. The digital engine provides the N-bits of digital output code in SAR conversion phase based on the digital signal and a voltage (Vcom) at the common terminal. During flash conversion phase, second ends of the first set of capacitors are connected to Vref and Vgnd respectively so as to generate a voltage level corresponding to the digital signal as Vcom.

Abstract: An input buffer for an Ultradeep Sub Micron (UDSM) process which allows the UDSM process to interface with a 3V input. The input voltage is applied to a degenerated transistor which forms part of the input buffer. The input buffer effectively drops the input voltage to a voltage suitable for use by the core of the UDSM process.

Abstract: A residue block in a stage of a pipeline ADC processing differential signals contains multiple pairs of capacitors. During a hold phase of operation, one capacitor of a pair is connected to a positive reference voltage, and the other capacitor is connected to a negative reference voltage if the input signal exceeds a corresponding threshold voltage. When the input signal does not exceed the corresponding threshold voltage, both capacitors of the pair are connected either to the positive or the negative reference voltage. As a result, the need for a common mode reference voltage may be eliminated, and the residue block can be implemented with a smaller area.

Abstract: A residue block in a stage of a pipeline ADC processing differential signals contains multiple pairs of capacitors. During a hold phase of operation, one capacitor of a pair is connected to a positive reference voltage, and the other capacitor is connected to a negative reference voltage if the input signal exceeds a corresponding threshold voltage. When the input signal does not exceed the corresponding threshold voltage, both capacitors of the pair are connected either to the positive or the negative reference voltage. As a result, the need for a common mode reference voltage may be eliminated, and the residue block can be implemented with a smaller area.

Abstract: An input buffer for an Ultradeep Sub Micron (UDSM) process which allows the UDSM process to interface with a 3V input. The input voltage is applied to a degenerated transistor which forms part of the input buffer. The input buffer effectively drops the input voltage to a voltage suitable for use by the core of the UDSM process.

Abstract: A clamping circuit containing a transistor and a current amplifier. The transistor is designed to turn on when the voltage at a node exceeds (falls below) a specified upper (lower) level. The current amplifier is designed to draw substantial amount of current when the transistor is turned on to clamp the voltage at the node to the desired level.

Abstract: Low voltage transistors are used in high voltage environment. The low voltage transistors may be used in the path of processing of a signal to increase the throughput performance. By using high voltage supply associated with the high voltage environment, a higher SNR may be attained. Various techniques are implemented to ensure that the low voltage transistors are not damaged by prolonged exposure to high voltages.

Abstract: A low-jitter clock distribution circuit, used in an integrated circuit having multiple analog-to-digital converters (ADCs), includes a plurality of cascaded inverters, each inverter including an upper P-channel transistor connected to a lower N-channel transistor. The ratio Wp/Wn of the widths of the P-channel and N-channel transistors in each inverter is equal to substantially the square root of the ratio Un/Up of the majority carrier mobilities of the N-channel and P-channel transistors as determined by the semiconductor fabrication process.

Abstract: An offset is used to correct the output of a charge coupled device (CCD). The correction to the offset is determined by an exponential curve which allows for greater correction when error is large, and little correction when the error is small. The exponential curve may be viewed as a sequence of connected linear segments, and the correction to the offset may be determined by the slope of the segment to which the error maps. As the slopes at large errors are steep, the slope is correspondingly high, and the offset converges towards the correct value quickly. Power consumption is optimized by implementing the offset generation circuit using capacitor charge sharing principles.

Abstract: An offset is used to correct the output of a charge coupled device (CCD). The correction to the offset is determined by an exponential curve which allows for greater correction when error is large, and little correction when the error is small. The exponential curve may be viewed as a sequence of connected linear segments, and the correction to the offset may be determined by the slope of the segment to which the error maps. As the slopes at large errors are steep, the slope is correspondingly high, and the offset converges towards the correct value quickly. Power consumption is optimized by implementing the offset generation circuit using capacitor charge sharing principles.