Abstract:
A phase interpolator, including: a pair of load resistors coupled to a supply voltage; a plurality of branches coupled to the pair of load resistors, each branch including a differential pair of transistors connected at source terminal to form a source node; a plurality of tail current sources, each tail current source coupled to one of the source nodes; and a plurality of coupling capacitors, each coupling capacitor coupled between the source nodes in two adjacent branches of the plurality of branches.
Abstract:
A phase interpolator, including: a first portion including a first plurality of branches and a plurality of tail current sources, each branch including a differential pair of transistors, source terminals of the differential pair of transistors connect to form a source node, wherein each tail current source couples to one of the source nodes, and wherein the differential pair of transistors and the corresponding tail current source are configured in a current coding scheme; a second portion including a second plurality of branches and a fixed current source coupled to the second plurality of branches, each branch of the second plurality of branches including a second plurality of differential pairs of transistors and a plurality of switches configured in a size coding scheme; wherein the first portion and the second portion are coupled to each other and to a pair of load resistors.
Abstract:
Systems and methods for decoding pulse-width modulated (PWM) data are disclosed. An example decoder filters a data input signal with a one-sided pulse filter. The one-sided pulse filter suppresses short pulses on the data input signal and passes long pulses. The example decoder latch the filtered data signal at the end of each bit time of the data input signal. The duration of pulses that are suppressed by the one-sided pulse filter can be calibrated to compensate for circuit variations and to allow the decoder to operate at various data rates. The decoder can be implemented in a small integrated circuit area and can be power efficient.
Abstract:
A bias structure includes a reference voltage node connected to gate structures of a first NMOS transistor and a second NMOS transistor, a bias voltage node comprising a bias voltage, and a first op amp having a first input connected to the reference voltage, a second input connected to a drain of the first NMOS transistor, and an output connected to gate structures of a first PMOS transistor and a second PMOS transistor. The bias structure further includes a second op amp having a first input connected to the reference voltage, a second input connected to a drain of the second NMOS transistor, and an output connected to a gate structure of a third NMOS transistor and the bias voltage node. The first NMOS transistor matches a transistor of a differential pair of an integrated circuit device.
Abstract:
Certain aspects are directed to an amplifier. The amplifier generally includes a first transistor having a gate coupled to an input node of the amplifier, a source degeneration circuit, and a second transistor coupled between the source degeneration circuit and a source of the first transistor, a gate of the second transistor being configured to receive a gain control signal from a controller.
Abstract:
In certain aspects, an apparatus includes a multiplexer having a first input, a second input, a select input, and an output, wherein the first input is configured to receive a first reference clock signal, the second input is configured to receive a second reference clock signal, and the select input is configured to receive a select signal. The multiplexer is configured to select one of the first and second reference clock signals based on the select signal, and output the selected one of the first and second reference clock signals at the output of the multiplexer. The apparatus also includes a clock driver having an input and an output, wherein the input of the clock driver is coupled to the output of the multiplexer.
Abstract:
A phase interpolator is provided with a plurality of slices. Each slice includes a first switch for mixing a first clock signal into an interpolated output signal and a second switch for mixing a second clock signal into the interpolated output signal. In response to a high-resolution signal, at least one of the slices may switch on both the first switch and the second switch.
Abstract:
A clock system including: an in-phase clock input and an in-phase clock output; a quadrature clock input and a quadrature clock output; a control loop configured to receive the in-phase clock output and the quadrature clock output, the control loop including a Boolean logic gate coupled to an operational amplifier (op-amp) through a low-pass filter; and an analog delay element coupled between the quadrature clock input and the quadrature clock output, the analog delay element comprising a plurality of capacitors.
Abstract:
Systems and methods for adjusting a phase step size of a clock data recover (CDR) circuit are described according to aspects of the present disclosure. In certain aspects, a method for adjusting a phase step size of a CDR circuit includes sensing a frequency offset of the CDR circuit, and adjusting the phase step size of the CDR circuit based on the sensed frequency offset. The frequency offset may be sensed by sensing a signal level on an integration path of a loop filter of the CDR circuit. The phase step size of the CDR circuit may be adjusted by switching the CDR circuit between a first phase step size and a second phase step size using a modulator (e.g., a sigma-delta modulator).
Abstract:
A phase interpolator is provided with a plurality of slices. Each slice includes a first switch for mixing a first clock signal into an interpolated output signal and a second switch for mixing a second clock signal into the interpolated output signal. In response to a high-resolution signal, at least one of the slices may switch on both the first switch and the second switch.