A semiconductor device includes a first chip and a second chip. The first chip includes a first circuit having a first output terminal. The second chip includes a second circuit having a second output terminal, which is electrically connected to the first output terminal via a first signal line. When the first chip and the second chip receive a first command, the second circuit calibrates an output impedance at the second output terminal through a first calibration operation based on an output impedance at the first output terminal.

First symbols are generated on a plurality of data channels by applying PAM-N encoding on a first subset of bits of a data burst, the first symbols generated without maximum transitions; second symbols are generated on at least one optionally-activated additional data channel, the second symbols generated by applying the PAM-N encoding on a second subset of bits of the data burst, the second symbols generated without maximum transitions; and third symbols are generated on a channel for communicating error correction bits for the first bits and second bits, the third symbols generated by applying hybrid PAM-N encoding on the error correction bits and a third subset of bits of the data burst, the hybrid PAM-N encoding comprising an interleaving of symbols with N voltage levels and symbols with less than N voltage levels.

An impedance calibration circuit includes a first variable impedance, a second variable impedance, a third variable impedance. The first variable impedance is connected to a ZQ terminal. A first control circuit performs a first impedance calibration on the first variable impedance based on an output signal from an output of a first comparator. A second control circuit performs a second impedance calibration on the third variable impedance based on an output signal from an output of a second comparator. A first switch connects an input of the first comparator to one of the ZQ terminal and the first node. A second switch connects the output of the first comparator to one of the first and second control circuits. A third switch connects an output of the first switch to one of first and second input terminals of the first comparator and connects the reference voltage to the other.

A driver for a shared bus, such as a LIN bus, having a supply node (Vbat), a bus node (LIN), a transmit data input node (TX) and a receive data output node (RX), said driver comprising: a pull-up circuitry between the supply node and the bus node, driver circuitry (100) having a control input connected to the transmit data input node, feedback circuitry (200) configured to provide feedback from the shared bus to the control input of the driver circuitry; said feedback circuitry comprising copy circuitry (210) configured to obtain at least one copy signal representative for a signal on the bus node, filter circuitry (220) configured to low-pass filter the at least one copy signal, derivative circuitry (230) configured to obtain at least one derivative signal representative for the speed at which the signal on the bus node varies.

An impedance calibration circuit is provided. The impedance calibration circuit includes a first calibration circuit, a second calibration circuit and a control circuit. The first calibration circuit is adapted to be coupled to an external resistor through a calibration pad, and generate a first voltage according to a first control signal and a resistance value of the external resistor. The second calibration circuit generates a second voltage according to the first control signal and a second control signal. The control circuit is configured to compare the first voltage and a reference voltage to obtain a first comparison result, and compare the first voltage and the second voltage to obtain a second comparison result, and generate the first control signal according to the first comparison result, and generate the second control signal according to the second comparison result.

An impedance calibration circuit includes first and second calibration circuits, a switch circuit and a control circuit. The first calibration circuit is coupled to an external resistance, and generates a first voltage. The second calibration circuit generates second and third voltages. The switch circuit is coupled to the first and second calibration circuits. The switch circuit selectively provides the first, second, and third voltages to first and second nodes. The control circuit is coupled to the first and second nodes. The control circuit generates first, second, and third control signals according to voltages of the first and second nodes. In a first time interval, the switch circuit provides the first voltage to the first and second nodes. In a second time interval, the switch circuit provides the second voltage to the first and second nodes, or provides the second and third voltages respectively to the first and second nodes.

An active termination circuit comprising an input node connected to a transmission line, a first transistor, and a second transistor. The transmission line supplies a signal to the input node. The first transistor is diode connected between a high voltage supply and the input node. The first transistor terminates the signal when the signal is at a low logic level. The second transistor is diode connected between the input node and a low voltage supply. The second transistor terminates the signal when the signal is at a high logic level.

An on-die termination circuit may include a resistance combination circuit, a first calibration circuit, a second calibration circuit, and a termination circuit. The resistance combination circuit may have an additional resistance value for setting a combined resistance value by combining the additional resistance value with a reference resistance value, and may be configured to set the additional resistance value based on a second calibration code. The first calibration circuit may be configured to generate a first calibration code corresponding to the reference resistance value or the combined resistance value according to a calibration sequence. The second calibration circuit may be configured to generate the second calibration code corresponding to the first calibration code. The termination circuit may be coupled to an input/output pad, and may be configured to set a termination resistance value corresponding to the first and second calibration codes.

An example analog signal multiplexer includes two differential input signal ports for receiving a first and a second differential input signals, IN1 and IN2. The multiplexer further includes a differential output signal port with two output terminals OUT+ and OUT−, for outputting a signal based on one or more of the input signals IN1 and IN2. Furthermore, the multiplexer includes a pair of load elements, and an additional differential output signal port that has two output terminals TERM+ and TERM−. The load elements are not coupled directly to the output terminals OUT+ and OUT−, but, rather, are coupled to the output terminals of the additional output signal port, TERM+ and TERM−, enabling a modular approach where multiple instances of the multiplexer may be combined on an “as-needed” basis to realize multiplexing between a larger number of differential inputs that a single multiplexer would allow.

In an example semiconductor device, the voltage/temperature conditions of the semiconductor device and associated calibration codes of multiple instances of ZQ calibrations are pre-stored in a register array. When a pre-stored voltage/temperature condition occurs again, ZQ calibration is not performed. Instead, the associated pre-stored calibration code is retrieved from the register array and provided to the IO circuit. When a voltage/temperature condition of the semiconductor device does not match any pre-stored voltage/temperature condition in the register array, a ZQ calibration is performed. When the ZQ calibration is performed, a register in the register array is selected according to an update policy and updated by the calibration code newly provided by the ZQ calibration along with the voltage/temperature condition at the time when the ZQ calibration is performed.