A current steering converter fabricated using a predetermined integrated circuit technology includes a unary portion having one or more current sources and a binary portion including a plurality of switches controlled by a decoder, the switches coupled to a converter output; and a plurality of devices commonly connected at a first end and coupled to each respective switch at a second end, wherein each device size comprises (W/L)*M, where W/L is a width and length of the device and M is an integer representing multiple number.

A power converter system for converting an input voltage at an input into an output voltage at an output may comprise a switch network comprising a reactive circuit element and a plurality of switches, switch control circuitry configured to operate the plurality of switch in a plurality of periodic, sequential states to regulate the output voltage, and reference current generating circuitry. The reference current generating circuitry may include a comparator coupled to a sensed switch of the plurality of switches and configured to compare a current flowing through the sensed switch to a reference current and current-steering circuitry coupled to the comparator configured to generate the reference current and alternate the reference current between a first reference current and a second reference current whenever the switch control circuitry changes from one state of the plurality of periodic, sequential states to another state of the plurality of periodic, sequential states.

A digital slope analog to digital converter includes a charge injection digital to analog converter (DAC) circuit, a comparator circuit, a detector circuit, and a control logic circuitry. The charge injection DAC circuit respectively samples input signals via first and second capacitors and generates a first signal via the first capacitor and a second signal via the second capacitor. The comparator circuit compares the first signal with the second signal to generate decision signals. The detector circuit generates a flag signal according to the decision signals. The control logic circuitry generates an enable signal according to the flag signal and generates a digital output when the comparator circuit detects a crossing point of the first and second signals. The charge injection DAC circuit gradually adjusts charges stored in the first and/or the second capacitor according to the enable signal until the crossing point is detected.

A combined I/Q DAC is provided with a plurality of sources corresponding to a plurality of selectors in which the corresponding source drives the corresponding selector with a source signal to produce a corresponding pair of in-phase and quadrature-phase analog input signals to a summation network. Each selector routes its source signal responsive to a digital value of a corresponding in-phase and quadrature-phase bit pair.

A digital/analog converter (DAC) includes a reference current generator including an internal resistor, and configured to generate reference current according to a resistance value of the internal resistor and a reference voltage, a digital gain block configured to generate a calibrated digital input signal that is obtained by adjusting a digital gain of a digital input signal based on a ratio between a reference resistance value and a resistance value of the internal resistor, and a conversion circuit configured to convert the calibrated digital input signal into an analog output signal, based on the reference current.

A DAC current steering circuit includes first and second transistors, respectively coupled to first and second outputs via first and second nodes at their drains, and source coupled to each other and to ground. A gate of the first transistor is coupled to a data input (D), and a gate of the second transistor coupled to a complement of the data input (DB). The circuit further includes first and second bleeder transistors, whose drains are respectively coupled to the first and second nodes, and whose sources are coupled together at a third node, the third node coupled to ground, and first and second bleeder switching transistors, whose drains and sources are each coupled to the third node, a gate of the first bleeder switching transistor coupled to a switching input (S) and a gate of the second bleeder switching transistor coupled to a complement of the switching input (SB).

A scaling apparatus and method for compensating nonlinearity due to the finite output impedance of current sources in current-steering digital-to-analog converters (DACs) are disclosed herein. In an example, a DAC may receive a digital input signal. The DAC may determine an output current weight for each of a plurality of unit cells, based on an output impedance of the unit cell. Further, the DAC may generate an analog output signal by applying the plurality of output current weights to the digital input signal. Then, the DAC may output the analog output signal. The analog output signal may be a high frequency analog output signal, which may be an optical high frequency analog output signal. In an example, a transfer curve of the analog output signal may be linear in terms of analog output signal voltage versus digital input code. The output current weights may include one or more polynomial terms.

Systems and techniques relating to a digital-to-analog converter (DAC) are described. A described DAC cell includes a differential switch pair coupled with a cross-coupled switch pair. Gate terminals of the differential switch pair are arranged to respectively receive an input signal to the cell and an inverted version of the input signal to respectively drive the gate terminals of the differential switch pair. Gate terminals of the cross-coupled switch pair are arranged to respectively receive the input signal and the inverted version of the input signal to respectively drive the gate terminals of the cross-coupled switch pair. The cross-coupled switch pair is configured to reduce or eliminate net differential transient current between switch output terminals of the differential switch pair. A current-to-voltage converter coupled with the switch output terminals of the differential switch pair generates a voltage that forms at least a portion of an output of the digital-to-analog converter.

An object is to improve Power Supply Rejection Ratio in a PLL circuit. A proportional path 103 is provided in a first power supply system 101 and outputs analog proportional signal AP according to a detection signal DET. An integral path 104 is provided in a second power supply system and outputs an analog integral signal AI according to the DET. A CCO driver 16 is provided in the first power supply system 101 and outputs control current ICCO according to the AP and the AI. A CCO 17 is provided in the second power supply system 102 and outputs an output signal Fout according to the ICCO. A phase frequency detector 11 is provided in the second power supply system 102 and configured to detect a phase difference between a reference signal Fref and a signal FM obtained by feeding back the Fout and then outputs the DET.

In accordance with an embodiment, a circuit includes a current digital-to-analog converter (DAC) having a current switching network coupled to a current DAC output, a first cascode current source coupled between a first supply node and the current switching network, a second cascode current source between a second supply node and the current switching network, and a shorting switch coupled between a first cascode node of the first cascode current source, and a second cascode node of the second cascode current source.