Abstract: A programmable gain amplifier that comprises: a transconductance amplifier, a switch leakage compensation circuit and a transimpedance amplifier. The transconductance amplifier provides a transconductance amplifier current signal and includes a switchable resistance network. The switch leakage compensation circuit provides a compensation current signal and comprises a switchable compensation resistance network. The transimpedance amplifier provides the output voltage signal based on the difference between the transconductance amplifier current signal and the compensation current signal. The switchable compensation resistance network comprises a plurality of branches in parallel with each other, wherein each branch includes: a gain-mimicking switch that has a corresponding gain-setting switch in the switchable resistance network; and a leakage-current-conducting switch in series with the gain-mimicking switch.

Abstract: A calibration apparatus for a communication system. The calibration apparatus is configured to: a) set a variable termination-resistance at a receiver to a predetermined value; b) cause a transmitter to send a calibration pattern to the receiver by: setting the differential voltage on the line to a non-zero value during a non-zero-phase; and setting the differential voltage on the line to zero during a subsequent zero-phase; c) compare the differential voltage on the line during the zero-phase with a reduced-bit-value-threshold, wherein the reduced-bit-value-threshold is less than a bit-value-threshold that is used during active communication. If the differential voltage on the line during the zero-phase exceeds the reduced-bit-value-threshold, then the calibration apparatus adjusts the value of the variable termination-resistance and returns to step b).

Abstract: A bandgap reference circuit includes a first current generator having first and second bipolar transistors for generating a first current that varies proportionally as a function of temperature. A second current generator includes a field effect transistor for generating a second current that varies inversely as a function of temperature. A trimming circuit includes a third bipolar transistor sized to match the first bipolar transistor, a third current generator having a second field effect transistor coupled to a collector and base of the third bipolar transistor to generate a third current based on a base current of the third bipolar transistor, and a trim control circuit configured to modify the second current by adding the third current to or subtracting the third current from the second current based on a trim control signal. A bandgap reference current is generated by summing the first current and the modified second current.

Abstract: A low voltage bandgap reference circuit (200) is provided which includes a first current generator (202) having first and second circuit branches which include, respectively, first and second bipolar transistors having different sizing reference values for generating a first current at a first resistor that varies proportionally as a function of temperature; a second current generator (204, 205) having a third circuit branch which includes one or more field effect transistors and no bipolar transistors for generating a second current that varies inversely as a function of temperature; and a third circuit (206) connected to generate a bandgap reference current in response to the first current and the second current.

Abstract: A low voltage bandgap reference circuit (200) is provided which includes a first current generator (202) having first and second circuit branches which include, respectively, first and second bipolar transistors having different sizing reference values for generating a first current at a first resistor that varies proportionally as a function of temperature; a second current generator (204, 205) having a third circuit branch which includes one or more field effect transistors and no bipolar transistors for generating a second current that varies inversely as a function of temperature; and a third circuit (206) connected to generate a bandgap reference current in response to the first current and the second current.