Abstract: Traditionally, constant current source circuits (and, in particular, constant current source circuits that include cascoded current sources) had numerous drawbacks due to parasitic capacitances, especially at higher switching frequencies. Here, however, a constant current source circuit is provided which uses main and replica constant current source circuitry (with buffering therebetween) to counteract the problems created by parasitic capacitances. Thus, with these new circuits, a generally constant current can be generated, regardless of switching frequency.

Abstract: An input signal to be sampled by a sample and hold circuit is amplified separately by two amplifiers. The output of the first amplifier is provided to a boost circuit to maintain the impedance of a sampling switch contained in a signal dependent boost switch substantially constant. The output of the second amplifier is sampled via the sampling switch, and the sample is stored in a storage element. The second amplifier drives a reduced load, and may be implemented as a low bandwidth, low power amplifier to reduce overall power consumption.

Abstract: A current source block provided according to an aspect of the present invention provides a substantially constant current even when the provision of the current is switched on and off at different frequencies. The current source block contains a main portion and a replica portion, with each portion having a current source and switches to connect output of the current source to corresponding output nodes. Additional connections are provided to enable the replica portion to counter deviations in the current output of the main portion due to parasitic effects. As a result, the current source block provides a constant current even when switched off/on at different (in particular high) frequencies. Such current source blocks may be used in components such as current steering DACs to obtain a linear response even at high operational frequencies.

Abstract: A stage of a pipelined ADC used as a sub-ADC in a time-interleaved ADC is operated using a first set of clock signals, with a next stage being operated using a second set of clock signals. The first set and second set of clock signals are designed to cause the start of hold phases of the stage to occur earlier than the sample phases of the next stage. In an embodiment, the start of the hold phases is coincident with the end of an immediately preceding sample phase of the stage. As a result, more time is provided for the output of an amplifier used in the stage to settle to a final value, thus permitting use of a low speed amplifier and reduction in power consumption in the interleaved ADC. In an embodiment, the stage corresponds to an earliest stage in the pipelined sub-ADC.

Abstract: An input signal to be sampled by a sample and hold circuit is amplified separately by two amplifiers. The output of the first amplifier is provided to a boost circuit to maintain the impedance of a sampling switch contained in a signal dependent boost switch substantially constant. The output of the second amplifier is sampled via the sampling switch, and the sample is stored in a storage element. The second amplifier drives a reduced load, and may be implemented as a low bandwidth, low power amplifier to reduce overall power consumption.

Abstract: A stage of a pipelined ADC used as a sub-ADC in a time-interleaved ADC is operated using a first set of clock signals, with a next stage being operated using a second set of clock signals. The first set and second set of clock signals are designed to cause the start of hold phases of the stage to occur earlier than the sample phases of the next stage. In an embodiment, the start of the hold phases is coincident with the end of an immediately preceding sample phase of the stage. As a result, more time is provided for the output of an amplifier used in the stage to settle to a final value, thus permitting use of a low speed amplifier and reduction in power consumption in the interleaved ADC. In an embodiment, the stage corresponds to an earliest stage in the pipelined sub-ADC.

Abstract: A voltage generation circuit generates a reference voltage using a bandgap reference. A countering circuit is included to adaptively counter for any deviations caused in a bandgap reference voltage such that the reference voltage is independent of fabrication process variations and changes in ambient temperature. In an embodiment, current, proportionate to deviation in absolute value of Vbe from a nominal value, is injected into an emitter-base junction to cause Vbe to equal the nominal value.

Abstract: A voltage generation circuit generating a reference voltage using a bandgap reference. A countering circuit is included to adaptively counter for any deviations caused in a bandgap reference voltage such that the reference voltage is independent of fabrication process variations and changes in ambient temperature. In an embodiment, current, proportionate to deviation in absolute value of Vbe from a nominal value, is injected into the emitter-base junction to cause Vbe to equal the nominal value.