Digital to analog (DAC) converter with current calibration

A digital to analog converter (DAC) comprising:

• a first sub-DAC configured to convert most significant bits (MSBs) of digital input data, the first sub-DAC including:
• a first array of current sources,
• first dynamic element randomizer circuitry configured to generate a first randomly modified data vector from a first thermometer coded data vector derived from the digital input data, and
• a first switch driver that controls coupling of the first array of current sources to a first output line or a second output line of the DAC based on the first randomly modified data vector;
• a second sub-DAC configured to convert at least some least significant bits (LSBs) of the digital input data, the second sub-DAC including:
• a second array of current sources including a calibration current source,
• second dynamic element randomizer circuitry configured to generate a second randomly modified data vector from a second thermometer coded data vector derived from the digital input data, and
• a second switch driver that controls coupling of the second array of current sources to the first output line or the second output line of the DAC based on the second randomly modified data vector;
• a third sub-DAC configured to convert other LSBs that are not converted by the second sub-DAC, the third sub-DAC including:
• a third array of current sources including a calibration current source,
• second dynamic element randomizer circuitry configured to generate a third randomly modified data vector from a third thermometer coded data vector derived from the digital input data, and
• a third switch driver that controls coupling of the third array of current sources to the first output line or the second output line of the DAC based on the third randomly modified data vector.

A digital to analog converter (DAC) comprising:

• a first sub-DAC configured to convert most significant bits (MSBs) of digital input data, the first sub-DAC including:
• a first array of current sources,
• first dynamic element randomizer circuitry configured to generate a first randomly modified data vector from a first thermometer coded data vector derived from the digital input data, and
• a first switch driver that controls coupling of the first array of current sources to a first output line or a second output line of the DAC based on the first randomly modified data vector;
• a second sub-DAC configured to convert at least some least significant bits (LSBs) of the digital input data, the second sub-DAC including:
• a second array of current sources including a calibration current source, second dynamic element randomizer circuitry configured to generate a second randomly modified data vector from a second thermometer coded data vector derived from the digital input data, and
• a second switch driver that controls coupling of the second array of current sources to the first output line or the second output line of the DAC based on the second randomly modified data vector;
• wherein the first array of current sources includes:
• a first switch;
• a second switch;
• a current source for each bit of the MSBs, each current source for each bit in the MSBs including a first terminal connected to a first voltage supply (VDD) and a second terminal connected to a first terminal of the first switch and a first terminal of the second switch, wherein
• the second terminal of the first switch is connected to the first output line,
• the second terminal of the second switch is connected to the second output line, and
• the first switch driver controls the first and second switches to couple the current source to the first output line or the second output line.

A digital to analog converter (DAC) comprising:

• a first sub-DAC configured to convert most significant bits (MSBs) of digital input data, the first sub-DAC including:
• a first array of current sources,
• first dynamic element randomizer circuitry configured to generate a first randomly modified data vector from a first thermometer coded data vector derived from the digital input data, and
• a first switch driver that controls coupling of the first array of current sources to a first output line or a second output line of the DAC based on the first randomly modified data vector;
• a second sub-DAC configured to convert at least some least significant bits (LSBs) of the digital input data, the second sub-DAC including:
• a second array of current sources including a calibration current source,
• second dynamic element randomizer circuitry configured to generate a second randomly modified data vector from a second thermometer coded data vector derived from the digital input data, and
• a second switch driver that controls coupling of the second array of current sources to the first output line or the second output line of the DAC based on the second randomly modified data vector;
• wherein:
• the first sub-DAC further includes a thermometer decoder configured to receive a first portion of the digital input data in binary format and provide the MSBs with the number of MSBs set to 1 equal to the first portion of the digital input data starting at bit 0;
• the second sub-DAC further includes a thermometer decoder configured to receive a second portion of the digital input data in binary format and provide the at least some LSBs with the number of the at least some LSBs set to 1 equal to the second portion of the digital input data starting at bit 0.

A method of converting digital data to analog data comprising:

• converting the digital data in binary format to thermometer bit vectors, wherein a first set of the thermometer bit vectors corresponds to most significant bits of the digital data and a second set of the thermometer bit vectors corresponds to least significant bits of the digital data;
• dynamically and randomly alternating connections of first current sources corresponding to the first set of the thermometer bit vectors to a first output line and a second output line;
• dynamically and randomly alternating connections of second current sources corresponding to the second set of the thermometer bit vectors to the first output line and the second output line;
• applying calibration current to the second current sources so a total current of the second current sources and the calibration current is within a predetermined range of an average current of the first current sources.