摘要:
A V.sub.BB input threshold potential with feedback circuitry is used to stabilize all of the logic inputs on an GaAs IC to ECL compatible levels over a normal temperature range and normal power supply variations. The system called "V.sub.BB -Feedback" uses "zero translation delay" direct Capacitor Diode Fet Logic (CDFL) inputs. This is an extension of the CDFL circuit approach in which the voltage across the input level shift circuitry on all inputs is adjusted to maintain a threshold voltage equal to the dc potential on an "extra" V.sub.BB input in spite of variations of temperature, power supply voltages or processing parameters such as MESFET pinchoff voltage. A dc potential (V.sub.BB) is applied to the "extra" V.sub.BB input, which is an additional input that is essentially identical to the actual logic inputs. All of the logic input threshold voltages are then slaved to the V.sub.BB dc potential applied to the "extra" V.sub.BB input. ECL compatability is accomplished by combining a reasonably compliant, but uniform, CDFL voltage shifter with feedback circuitry to maintain the shift voltages at proper levels thereby achieving the desired input logic threshold.
摘要:
A circuit that provides a termination resistance to a transmission line includes a controllable termination resistor coupled between the transmission line and a termination voltage node. The circuit also includes a control circuit coupled to the controllable termination resistor and to a reference resistor. The control circuit matches the resistance of the controllable termination resistor to the resistance of the reference resistor.
摘要:
In embodiments of a high-speed I/O data system, a first computer chip includes a data transmission system, and a second computer chip includes a data reception system. A data channel communicates an NRZ data signal, and a clock channel communicates a forwarded clock signal, from the data transmission system to the data reception system. The data transmission system includes a first differential serializing transmitter to generate the NRZ data signal from pulsed data, and further includes a second differential serializing transmitter to generate a forwarded clock signal. A first multi-phase transmit clock generator generates transmit clock signals for the first and second differential serializing transmitters. The data reception system includes a data receiver and a de-serializer to receive and de-serialize the NRZ data signal, and includes a multi-phase receive clock generator to generate receive clock signals from the forwarded clock signal for the de-serializing data receiver.
摘要:
A serial data communication receiver includes a serial data input, first and second equalizers, first and second capture latch circuits, and an equalization control circuit. The first and second equalizers are coupled to the serial data input and have first and second equalized serial data outputs, respectively. Each equalizer has a frequency response that is variable over a range of frequency response settings. The first and second capture latch circuits are coupled to the first and second equalized serial data outputs, respectively, in a phase-locked loop and have first and second recovered data outputs, respectively. The equalization control circuit measures a data eye size of the second equalized serial data output over the range of frequency response settings of the second equalizer and sets the frequency response of the first equalizer to one of the frequency response settings based on the measured data eye sizes.
摘要:
A data serializer includes a differential output stage. The differential output stage has n pairs of first and second control inputs, wherein each pair of control inputs corresponds to one of n data inputs. Each pair of first and second control inputs is driven by first and second logic AND circuits having p-channel output drive transistors.
摘要:
A data serializer includes a differential output stage. The differential output stage has n pairs of first and second control inputs, wherein each pair of control inputs corresponds to one of n data inputs and n is an integer greater than one. Each pair of first and second control inputs is driven by a respective logic AND circuits having a rise time controlled by a first adjustable controlled current source and a fall time controlled by a second adjustable controlled current source.
摘要:
A differential output buffer includes first and second complementary data inputs, an idle input, and a differential output stage having first and second output stage control inputs and first and second differential data outputs. First and second push-pull circuits charge one of the first and second output stage control inputs toward a logic high voltage and discharge the other of the first and second output stage control inputs toward a logic low voltage based on relative logic states of the first and second data inputs. A logic low voltage supply generator is coupled to the idle input and the logic low voltage supply terminal for setting the logic low voltage as a function of the idle input.
摘要:
A data transmission circuit for transmitting a data stream includes a voltage supply terminal, a resistively terminated, controlled-impedance transmission line and an inductor coupled between the voltage supply terminal and the controlled-impedance transmission line.
摘要:
An integrated circuit phase-locked loop includes a phase/frequency detector, a charge pump, and a voltage-controlled oscillator (VCO) which are coupled together in series. The VCO has first and second VCO control inputs, and has a VCO output which is coupled to the phase/frequency detector. An off-chip loop filter input is coupled between the charge pump and the first VCO control input for coupling to an off-chip loop filter. An on-chip loop filter is coupled between the first VCO control input and the second VCO control input. The VCO has a lower voltage-to-frequency gain from the first VCO control input to the VCO output than from the second VCO control input to the VCO output.
摘要:
A time-division data multiplexer has feedback for adjusting the select clock cross-over voltage. The multiplexer includes a multi-phase clock generator having a plurality of select clock outputs with different phases, a plurality of parallel data inputs and first and second serial data outputs. A first set of gating transistors is coupled between the first data output and a common node. Each transistor in the first set is gated by a corresponding data input and at least one corresponding select clock output. A second set of gating transistors is coupled between the second data output and the common node. Each transistor in the second set is gated by a corresponding data input and at least one corresponding select clock output. A first current source is coupled to the common node. An amplifier has a first input which is coupled to the common node, a second input which is coupled to a reference voltage generator and a cross-over control output which is coupled to the plurality of select clock outputs for adjusting the cross-over voltage of the select clock outputs in response to a comparison of the voltages on the first and second amplifier inputs. A loop filter is coupled to the cross-over control output.