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US 12,470,213 B2Granted
High speed high swing driver for direct drive photonic modulators
AssigneeCiena Corporation
InventorsFaisal Ahmed Musa, Ahmed Mustafa, Naim Ben Hamida, Bruce Beggs
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Abstract
An integrated circuit device includes a digital-to-analog converter with multiple bit slices, each bit slice having a differential pair of driver transistors. A driver circuit includes the differential pairs of driver transistors, multiple series cascode transistors, and current bleed paths to modify drain-to-source currents in the various cascode transistors. Additional embodiments include series peaking circuits, back termination networks, and neutralization capacitors. Other embodiments are disclosed.
Claims20
A device comprising:
- a first differential pair of transistors having drain nodes coupled to a differential pair of combiner nodes, having source nodes coupled in common to a first tail current source, and having gate nodes coupled to output nodes of a pre-driver stage;
- a first pair of cascode transistors having drain nodes, gate nodes coupled in common to a first cascode bias node, and source nodes coupled to the differential pair of combiner nodes, the first pair of cascode transistors having a first breakdown voltage;
- a second pair of cascode transistors having drain nodes, source nodes coupled to the drain nodes of the first pair of cascode transistors, and gate nodes coupled in common to a second cascode bias node, the second pair of cascode transistors having a second breakdown voltage, wherein the second breakdown voltage is higher than the first breakdown voltage;
- and
- an output network coupled to the drain nodes of the second pair of cascode transistors.
2 more elements
A device comprising:
- a plurality of pairs of differential transistors having drain nodes coupled to a pair of differential combiner nodes, wherein each pair of differential transistors of the plurality of pairs of differential transistors have source nodes coupled in common to a corresponding one current source of a plurality of current sources;
- a pair of differential output nodes;
- a double cascode network of transistors coupled between the pair of differential combiner nodes and the pair of differential output nodes;
- and
- at least one current bleed path coupled to the double cascode network of transistors, wherein the at least one current bleed path is configured to provide a drain-to-source current through at least one transistor of the double cascode network of transistors.
2 more elements
A method, comprising:
- providing a first pair of cascode transistors having a first breakdown voltage, wherein the first pair of cascode transistors are coupled to an output of a differential amplifier;
- providing differential output nodes;
- providing a second pair of cascode transistors having a second breakdown voltage, wherein the second pair of cascode transistors are coupled between the first pair of cascode transistors and the differential output nodes, and wherein the second breakdown voltage is greater than the first breakdown voltage.
Dependencies are inferred from the claim text.