Abstract: A cable detector includes one or more peak detectors that detect when a termination impedance is missing from the output of a line driver. A peak detection signal is asserted when signals on a transmission line exceed a threshold level. A fault condition is asserted when the peak detection signal is asserted for a sufficient length of time to indicate that an actual fault is detected. The time period required for detecting a lost or missing line termination is longer than the time periods for any one of the pathological conditions to avoid a false positive detection. After the peak detection signal is de-asserted, the fault condition will be maintained until another sufficient length of time has expired without a peak detection.

Abstract: A skew measurement system and method wherein each of the signals among which the skew is to be determined is connected one at a time to a clock recovery loop. The locked state of the clock recovery loop is used as an indicator of the skew of the data signal relative to the internal clock of the clock recovery loop. By measuring the difference between the locked state of different signals, their relative skew can be measured.

Abstract: A serial communication interface driver is provided wherein current steering switches are also used to provide termination impedances. The output voltage can be produced by a voltage-dividing current path between two regulated voltages, which provides improved efficiency.

Abstract: A circuit and method are provided for performing built-in test of output signal magnitudes of integrated differential signal generator circuitry. In accordance with one embodiment, first upper and lower reference voltages and second upper and lower reference voltages are received via a plurality of reference electrodes, wherein: a difference between the first and upper and lower reference voltages comprises a first difference magnitude; a difference between the second upper and lower reference voltages comprises a second difference magnitude; and the first difference magnitude is greater than the second difference magnitude. Test signal generator circuitry provides a plurality of binary signals with respective successions of opposing signal states.

Abstract: An RC calibration circuit, which utilizes a resistor and a variable capacitor connected in parallel, reduces power consumption and increases the accuracy of the calibration by comparing the voltage on the resistor to the voltage on the capacitor after a predetermined time has expired since the capacitor began charging up. The result of the comparison, which indicates whether the voltage on the resistor is greater than the voltage on the capacitor, is then used to adjust the capacitance of the capacitor to servo the RC time constant to a predetermined value.

Abstract: A line driver outputs a pair of transmit signals TX+ and TX− that have substantially reduced output level variations due to variations in process, voltage, and temperature. The reduced output level variations are provided by varying the magnitude of the current that sets up the voltages of the transmit signals in a manner that offsets variations in the power supply voltage, temperature, and process, and by limiting variations of the bandgap current source to process and temperature only.