System and method for array diagnostics in superconducting integrated circuit
First Claim
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1. A superconducting digital system, comprising:
- a plurality of nominally identical devices under test, each device configured to generate at least one SFQ pulse output in response to an excitation condition;
a port configured to provide a common excitation condition to each of the devices under test; and
a superconducting digital multiplexer comprising;
a plurality of input ports, one for each nominally identical device under test, configured to accept the at least one SFQ pulse output of a respective device under test;
an output port, configured to propagate the at least one SFQ pulse; and
a selectable switch, configured to cause the output port to reproduce the at least one SFQ pulse from a respective single input port to preserve information comprising a statistical variation of the reproduced at least one SFQ pulse from the respective single input port under the common excitation condition, while blocking propagation of SFQ pulses present on all other of the plurality of input ports, dependent on a selectable state.
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Abstract
A superconducting circuit is disclosed for fast digital readout of on-chip diagnostics in an array of devices in an integrated circuit. The digital readout comprises a digital RSFQ multiplexer to select the readout channel. This permits a large number of devices to be tested with a minimum of input and output lines. The devices may comprise digital devices (such as elementary RSFQ cells), or analog devices (such as inductors, resistors, or Josephson junctions) with a SQUID quantizer to generate a digital signal. The diagnostic array and the digital multiplexer are preferably configured to operate as part of the same integrated circuit at cryogenic temperatures.
630 Citations
23 Claims
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1. A superconducting digital system, comprising:
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a plurality of nominally identical devices under test, each device configured to generate at least one SFQ pulse output in response to an excitation condition; a port configured to provide a common excitation condition to each of the devices under test; and a superconducting digital multiplexer comprising; a plurality of input ports, one for each nominally identical device under test, configured to accept the at least one SFQ pulse output of a respective device under test; an output port, configured to propagate the at least one SFQ pulse; and a selectable switch, configured to cause the output port to reproduce the at least one SFQ pulse from a respective single input port to preserve information comprising a statistical variation of the reproduced at least one SFQ pulse from the respective single input port under the common excitation condition, while blocking propagation of SFQ pulses present on all other of the plurality of input ports, dependent on a selectable state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of digital readout of an array comprising a plurality of elements in a superconducting integrated circuit, comprising the steps of:
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(a) exciting the array comprising the plurality of elements in a continuous or periodic fashion; (b) generating a sequence of SFQ pulses from each element of the array while subject to the respective excitation comprising a statistical variation of the sequence of pulses for each of the plurality of elements; (c) conducting the sequence of pulses for each of the plurality of elements to a corresponding plurality of inputs of a digital multiplexer to preserve information comprising the statistical variation of the sequence of pulses for each of the plurality of elements; and (d) selecting a state, within the digital multiplexer, to permit the pulses of only a single selected input of the plurality of inputs for output on a multiplexer output line. - View Dependent Claims (17, 18, 19, 20, 21, 22)
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23. A superconducting digital multiplexer system for testing a plurality of nominally identical devices under test, each device configured to generate at least one SFQ pulse output in response to an excitation condition the system comprising:
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a plurality of input ports, a respective input port for each nominally identical device under test, configured to accept the at least one SFQ pulse output of a respective device under test; a port configured to provide a common excitation condition to each of the nominally identical devices under test; an output port, configured to propagate the at least one SFQ pulse; and a selectable switch, configured to cause the output port to reproduce the at least one SFQ pulse from a respective single input port to preserve information comprising a statistical variation of the reproduced at least one SFQ pulse from the respective single input port while under the common excitation condition, while blocking propagation of SFQ pulses present on all other of the plurality of input ports, dependent on a selectable state.
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Specification