Apparatus having source follower based DAC inter-symbol interference cancellation
AssigneeTexas Instruments Incorporated
InventorsShagun Dusad, Eeshan Miglani, Sandeep Jhanwar
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Abstract
A current digital-to-analog converter (DAC) and an integrated circuit chip including the DAC are disclosed. The current DAC includes a switching circuit that includes a plurality of switches coupled to receive differential digital control signals and to provide first and second differential current outputs, a current source coupled to an upper rail and to a first node of the switching circuit, a first current sink coupled to a lower rail and to a second node of the switching circuit, and an interference cancellation circuit coupled to substantially prevent a tail capacitance current from flowing through the first and second differential current outputs.
Claims18
A current digital-to-analog converter (DAC) comprising:
- a switching circuit comprising a plurality of switches coupled to receive differential digital control signals and to provide first and second differential current outputs;
- a current source coupled to an upper rail and to a first node of the switching circuit;
- a first current sink coupled to a lower rail and to a second node of the switching circuit;
- and
- an interference cancellation circuit coupled to substantially prevent a tail capacitance current from flowing through the first and second differential current outputs.
An integrated circuit (IC) chip comprising:
- a loop filter;
- and
- a digital-to-analog converter (DAC) coupled to provide first and second differential current outputs towards the loop filter, the DAC comprising a plurality of DAC elements, the DAC elements each comprising:
- a switching circuit comprising a plurality of switches coupled to receive respective differential digital control signals and to provide respective first and second differential current outputs;
- a current source coupled to an upper rail and to a first node of the switching circuit;
- a first current sink coupled to a lower rail and to a second node of the switching circuit;
- and
- an interference cancellation circuit coupled to substantially prevent a tail capacitance current from flowing through the first and second differential current outputs.
Dependencies are inferred from the claim text.