Embodiments generally relate to a conversion arrangement, a driver arrangement, and a method of producing a complementary complementary metal-oxide-semiconductor (CMOS) output signal for driving a modulator device. The conversion arrangement includes a differential amplifier configured to produce a first amplified signal based on the differential input signal, and at least two transimpedance amplifiers (TIAs) coupled with respective outputs of the differential amplifier and configured to produce a second amplified signal based on the first amplified signal. Respective bias voltages for the TIAs are based on the first amplified signal. The conversion arrangement further includes a common-mode feedback arrangement coupled with outputs of the TIAs and configured to control the first amplified signal based on the second amplified signal, thereby controlling the bias voltages, wherein the complementary CMOS output signal is based on the second amplified signal.

An apparatus includes: a first transconductance device of a first type configured to convert a first voltage into a first current of an output node; a second transconductance device of a second type configured to convert a second voltage into a second current of the output node; a common mode feedback circuit coupled to the output node configured to control a mean voltage at the output node in accordance with a reference voltage; and a reset circuit configured to reset a voltage at the output node in accordance with a clock signal.

Certain aspects of the present disclosure provide methods and apparatus for adjusting a bandwidth of an amplifier (e.g., a programmable gain amplifier (PGA)). In certain aspects, the PGA generally includes at least one amplification stage having an input and an output, a plurality of compensation capacitors, and at least one first switch configured to selectively couple at least one capacitor of the plurality of compensation capacitors between the input and the output of the at least one amplification stage. In certain aspects, the amplifier includes at least one second switch configured to selectively couple the at least one capacitor to a node such that the at least one capacitor is coupled to only one of the output or the node, where a voltage at the node is a differential mode (DM) reference potential for the amplification stage.

A variable gain amplifier circuit includes a differential pair of transistors and a variable current source circuit. The differential pair of transistors generates an output signal based on an input signal. The variable current source circuit is coupled to the differential pair of transistors. A gain of the output signal relative to the input signal varies in response to variations in a bias current through the variable current source circuit. The variable gain amplifier circuit maintains a common mode voltage of the output signal substantially constant in response to the variations in the bias current through the variable current source circuit.

Disclosed is a four-phase generation circuit, comprising a pair of input ports configured to receive a differential signal having a common mode voltage; a polyphase filter having a pair of polyphase filter input ports and first, second, third and fourth output ports; a first circuit configured to provide the differential signal with an adjusted common mode voltage to the pair of polyphase filter input ports; wherein the first, second third and fourth output ports are each configured to output a square-wave signal, with 90 phase separation between consecutive output signals; and a feedback circuit from the first, second, third and fourth outputs ports to the first circuit; wherein the feedback circuit is configured to provide a feedback signal to the first circuit to set the adjusted common mode voltage from the common mode voltage.