A preamplifier circuit includes a first transconductor and a floating transconductor. The first transconductor receives a differential voltage from a sample-and-hold circuit and drives the floating transconductor. The first and floating transconductors output amplified versions of the differential voltage that are not affected by capacitive division, which makes the preamplifier circuit fast. The preamplifier circuit also has a low input capacitance because the floating transconductor is not connected to any external circuitry.

A Low-Voltage Differential Signaling (differential signaling) driver circuit (10) comprising enable circuitry for enabling and disabling the differential signaling driver circuit (10) in accordance with an control signal is described. The differential signaling driver circuit (10) comprises: a differential output (12, 13) connected or connectable to a differential signaling receiver circuit via a differential transmission line; current control circuitry (14) for driving a signal current through the differential output (12, 13) in accordance with a driver signal; feedback circuitry (16) for driving the current control circuitry (14) to counteract a difference between a common mode voltage of the differential output (12, 13) and a reference voltage from a reference voltage provider; and the enable circuitry (18). The feedback circuitry (16) comprises a common mode node (20) for providing the common mode voltage (Vcm), a reference input (22) connected or connectable to the reference voltage provider, and a feedback input (24). The enable circuitry (18) is arranged to connect the feedback input (24) to the common mode node (20) when the differential signaling driver circuit (10) is in an enabled state and to the reference voltage provider when the differential signaling driver circuit (10) is in a disabled state. A method of enabling (5.1) and disabling (5.2) a Low-Voltage Differential Signaling (differential signaling) driver circuit (10) is also proposed.

A phase rotator apparatus has phase interpolation and transimpedance amplifier (TIA) stages. This separates gain and bandwidth as degrees of design freedom, facilitating a reduction in power consumption while enabling the data link to transmit and receive higher speed data. Four phases of an incoming signal are combined by the phase interpolation stage using weighting currents and current-source loads to produce a phase shifted current based signal that the TIA stage receives as input. The TIA stage then converts the signal to a voltage based signal. The quiescent operating voltage of the stage outputs can be maintained with common mode feedback circuits and injector currents.

An amplifier device includes an amplifier circuit, a feedback circuit, and a filter circuit. The amplifier circuit is configured to receive an input signal and a filtered signal, and to output a first output signal and a second output signal at a first output terminal and a second output terminal respectively. The first output signal and the second output signal are a pair of differential signals. The feedback circuit is configured to set direct current (DC) voltage levels of the first output signal and the second output signal to be at a predetermined voltage. The filter circuit is configured to low-pass filter the input signal or to low-pass filter the pair of differential signals so as to generate the filtered signal, and is configured to output the filtered signal to the amplifier circuit.

An amplifier device includes an amplifier circuit, a feedback circuit, and a filter circuit. The amplifier circuit is configured to receive an input signal and a filtered signal, and to output a first output signal and a second output signal at a first output terminal and a second output terminal respectively. The first output signal and the second output signal are a pair of differential signals. The feedback circuit is configured to set direct current (DC) voltage levels of the first output signal and the second output signal to be at a predetermined voltage. The filter circuit is configured to low-pass filter the input signal or to low-pass filter the pair of differential signals so as to generate the filtered signal, and is configured to output the filtered signal to the amplifier circuit.