An operational amplifier with totem pole connected output transistors having inputs coupled to multiplexers for selectable coupling of signals and voltage levels thereto. The high and low output transistors may be forced hard on or hard off in addition to normal coupling of signals thereto. The operation of the output transistors may be dynamically changed to pass only positive going signals, negative going signals, placed in a tristate high impedance state, hard connected to a supply voltage and/or hard connected to supply common return. A core independent peripheral (CIP) may also be coupled to the operational amplifier for dynamically changing the multiplexer inputs in real time, as can external control signals to a control circuit coupled to the multiplexers.

A (pre) driver circuit includes first and second output terminals configured to be coupled to a power transistor. A differential stage has non-inverting and inverting inputs for receiving an input voltage. The input voltage is replicated as an output voltage across the first and second output terminals as a drive signal for the power transistor. The differential stage includes a differential transconductance amplifier in a voltage follower arrangement configured to provide continuous regulation of a voltage at the first output terminal with respect to the second output terminal.

An apparatus, such as a coherent optical receiver, includes a trans-impedance amplifier (TIA) and a low dropout (LDO) voltage regulator circuit for providing a supply voltage to the TIA. The LDO circuit is configured to adjust the supply voltage responsive to a DC voltage at an output of the TIA. In some implementations the LDO circuit may provide only a fraction of a supply current to the TIA, with another fraction provided by a partial current replica source.

A common-mode feedback circuit includes a transconductor input stage with differential input terminals, and a frequency-compensated gain stage coupled to the transconductor input stage with differential output terminals. The common-mode feedback circuit also includes a feedback loop having a comparator configured to produce a feedback error signal for the transconductor input stage by comparing with a reference a common-mode sensing signal indicative of a common-mode voltage level sensed at the differential output terminals. In addition, the common-mode feedback loop includes a converter for converting the common-mode voltage level sensed at said differential output terminals into a current signal coupled to the comparator.

An attenuation device for a CAN transceiver comprises two device output nodes configured to electrically couple the attenuation device via the device output nodes between two transceiver terminals of the CAN transceiver. The attenuation device is configured to change from a first device state to a second device state when a common mode voltage is applied to the device output nodes that is either greater than a first reference voltage or less than a second reference voltage that is less than the first reference voltage. The attenuation device causes a first electrical output resistance at each device output node during the first device state and causes a second electrical output resistance at each device output node during the second device state in which the second output resistance is less than the first output resistance.

A (pre) driver circuit includes first and second output terminals configured to be coupled to a power transistor. A differential stage has non-inverting and inverting inputs for receiving an input voltage. The input voltage is replicated as an output voltage across the first and second output terminals as a drive signal for the power transistor. The differential stage includes a differential transconductance amplifier in a voltage follower arrangement configured to provide continuous regulation of a voltage at the first output terminal with respect to the second output terminal.

Method and implementation of gain-bandwidth product (GWB) tuning are disclosed. In an embodiment an operational amplifier (opamp) includes an input stage of the opamp including a differential device pair coupled to a tail device and configured to be responsive to a differential input signal for conducting a first current and an output stage of the opamp including a class AB interface stage circuit and a pair of output devices connected to the class AB interface stage circuit, wherein a first constant gm bias circuit is coupled to an input terminal of the class AB interface stage circuit.

A common-mode feedback circuit includes a transconductor input stage with differential input terminals, and a frequency-compensated gain stage coupled to the transconductor input stage with differential output terminals. The common-mode feedback circuit also includes a feedback loop having a comparator configured to produce a feedback error signal for the transconductor input stage by comparing with a reference a common-mode sensing signal indicative of a common-mode voltage level sensed at the differential output terminals. In addition, the common-mode feedback loop includes a converter for converting the common-mode voltage level sensed at said differential output terminals into a current signal coupled to the comparator.

Method and implementation of gain-bandwidth product (GWB) tuning are disclosed. In an embodiment an operational amplifier (opamp) includes an input stage of the opamp including a differential device pair coupled to a tail device and configured to be responsive to a differential input signal for conducting a first current and an output stage of the opamp including a class AB interface stage circuit and a pair of output devices connected to the class AB interface stage circuit, wherein a first constant gm bias circuit is coupled to an input terminal of the class AB interface stage circuit.

A common-mode feedback circuit includes a transconductor input stage with differential input terminals, and a frequency-compensated gain stage coupled to the transconductor input stage with differential output terminals. The common-mode feedback circuit also includes a feedback loop having a comparator configured to produce a feedback error signal for the transconductor input stage by comparing with a reference a common-mode sensing signal indicative of a common-mode voltage level sensed at the differential output terminals. In addition, the common-mode feedback loop includes a converter for converting the common-mode voltage level sensed at said differential output terminals into a current signal coupled to the comparator.