A signaling circuit having a selectable-tap equalizer. The signaling circuit includes a buffer, a select circuit and an equalizing circuit. The buffer is used to store a plurality of data values that correspond to data signals transmitted on a signaling path during a first time interval. The select circuit is coupled to the buffer to select a subset of data values from the plurality of data values according to a select value. The equalizing circuit is coupled to receive the subset of data values from the select circuit and is adapted to adjust, according to the subset of data values, a signal level that corresponds to a data signal transmitted on the signaling path during a second time interval.

According to one embodiment, in a semiconductor integrated circuit, a variable delay circuit is electrically connected to the correction circuit and configured to change a delay amount of the second clock. An adjustment circuit is electrically connected to a summer circuit. The adjustment circuit is configured to perform sampling of values in a plurality of edge periods and values in a plurality of data periods of data output from the summer circuit, and adjust a delay amount of the variable delay circuit such that timing of the second clock supplied from the variable delay circuit to the correction circuit becomes close to target timing according to a plurality of sampling results.

An electronic circuit including: a driver for outputting a driven first signal by driving a first signal among signals received in parallel; a selector circuit for selecting one of the first signal and a second signal among the signals received in parallel; and a compensator circuit for generating a first compensation signal for compensating the driven first signal, in response to the first signal or the second signal selected by the selector circuit, wherein, when the selector circuit selects the first signal, the compensator circuit generates the first compensation signal to compensate for an inter-symbol interference of the driven first signal, and wherein, when the selector circuit selects the second signal, the compensator circuit generates the first compensation signal to compensate for a crosstalk noise of the driven first signal caused by a driven second signal driven from the second signal.

A signaling circuit having a selectable-tap equalizer. The signaling circuit includes a buffer, a select circuit and an equalizing circuit. The buffer is used to store a plurality of data values that correspond to data signals transmitted on a signaling path during a first time interval. The select circuit is coupled to the buffer to select a subset of data values from the plurality of data values according to a select value. The equalizing circuit is coupled to receive the subset of data values from the select circuit and is adapted to adjust, according to the subset of data values, a signal level that corresponds to a data signal transmitted on the signaling path during a second time interval.

A serial data channel includes a transmitter that encodes serial data using a quaternary PAM-4 scheme, wherein the four PAM-4 signal levels include two balanced pairs of differential signal levels. The channel includes a de-emphasis circuit that determines that first and second symbols are in a first PAM-4 state, that a third symbol is in a second PAM-4 state, and provides a first de-emphasis to a voltage level of the second symbol in response to determining that the third symbol is represented as the second state. The de-emphasis circuit further determines that fourth and fifth symbols are in the second state, that a sixth symbol is in the first state, and provides a second de-emphasis to a voltage level of the fifth symbol in response to determining that the sixth symbol is represented as the first state. The first de-emphasis and the second de-emphasis represent different de-emphasis levels.

A decision feedback equalizer (DFE) comprises two charge-steering (CS) input latches driven by complementary -rate clocks, two pairs of CS primary latches, and two pairs of taps. The primary latches are driven by -rate clocks. In a first aspect, each one of the input latches and the primary latches includes a respective differential pair of n-channel output transistors, and each tap includes a respective differential pair of p-channel input transistors. In a second aspect, each one of the input latches and the primary latches includes a respective differential pair of p-channel input transistors, and each tap includes a respective differential pair of n-channel output transistors. In some implementations, no element of any one of the taps is driven by any -rate clock. In some implementations, every switch of at least one of the taps is driven by one of the -rate clocks.

A decision feedback equalizer includes a summer, a slicer, and a feedback circuit. The summer is configured to receive an input signal and a correction signal from the feedback circuit and generate a summer output signal. The slicer includes a first slicer and a second slicer, both are configured to receive the summer output signal as an input, and output a slicer output signal. The feedback circuit is configured to receive the slicer output signal, and based on the slicer output signal, generate the correction signal. The input signal is received at a first clock rate. The first slicer and the second slicer sample the input signal at a second clock rate, about half the first clock rate.

A reception device for receiving a data signal representing a data value 0 or 1. The reception device includes an equalizer circuit and a control circuit. The equalizer circuit outputs an output value representing a result obtained by comparing a voltage based on the received data signal and a first voltage as a reference, at each clock timing corresponding to the data signal. The control circuit is connected to the equalizer circuit. The control circuit changes, before the data signal is received, a tap coefficient related to a characteristic of the equalizer circuit in a state in which a second voltage different from the first voltage, instead of the voltage of the data signal, is supplied to the equalizer circuit, to detect an inverted tap coefficient that is the tap coefficient at a boundary where a data value of the output value is inverted. The control circuit sets the inverted tap coefficient to the equalizer circuit at a time of receiving the data signal.

A signaling circuit having a selectable-tap equalizer. The signaling circuit includes a buffer, a select circuit and an equalizing circuit. The buffer is used to store a plurality of data values that correspond to data signals transmitted on a signaling path during a first time interval. The select circuit is coupled to the buffer to select a subset of data values from the plurality of data values according to a select value. The equalizing circuit is coupled to receive the subset of data values from the select circuit and is adapted to adjust, according to the subset of data values, a signal level that corresponds to a data signal transmitted on the signaling path during a second time interval.

To improve on power and bandwidth limitations associated with conventional feedforward equalizer (FFE) implementations, the present disclosure provides intersymbol interference (ISI) compensation circuits that do not use delay cells common to FFE structures. In one example, the compensation circuit of the present disclosure comprises a two stage amplifier. Each stage of the amplifier is implemented using a differential pair with degeneration. One of the amplifier stages has a transfer function with a zero in the left half of the s-domain, also called the s-plane, and the other amplifier has a transfer function with a zero in the right half of the s-domain. The amplifier stage with the zero in the left half of the s-domain can be used to provide post-cursor ISI compensation, and the amplifier stage with the zero in the right half of the s-domain can be used to provide pre-cursor ISI compensation.