Current-mode logic circuit having a wide operating range
AssigneeXilinx, Inc.
InventorJunho Cho
Life of this patent
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Abstract
In one example, a current-mode logic (CML) circuit includes a differential transistor pair having a differential input port configured to receive a differential input voltage, a bias port configured for coupling to a current source, and a differential output port. The CML circuit further includes a load circuit coupled to the differential output port. The load circuit includes an active inductive load, a cross-coupled transistor pair, and a switch coupled between the cross-coupled transistor pair and the differential output.
Claims20
A current-mode logic (CML) circuit, comprising:
- a differential transistor pair having a differential input port configured to receive a differential input voltage, a bias port configured for coupling to a current source, and a differential output port;
- and
- a load circuit coupled to the differential output port, the load circuit comprising:
- an active inductive load;
- a cross-coupled transistor pair having sources directly coupled to a supply voltage;
- and
- a switch coupled between drains of the cross-coupled transistor pair and the differential output.
The CML circuit of 1, wherein the differential transistor pair comprises a pair of n-channel transistors having respective drains coupled to the differential output port, respective gates coupled to the differential input port, and respective sources coupled to the bias port.
A current-mode logic (CML) circuit, comprising:
- a plurality of CML cells coupled to perform a logic operation, each of the CML cells comprising:
- a differential transistor pair having a differential input port configured to receive a differential input voltage, a bias port configured for coupling to a current source, and a differential output port;
- and
- a load circuit coupled to the differential output port, the load circuit comprising:
- an active inductive load;
- a cross-coupled transistor pair having sources directly coupled to a supply voltage;
- and
- a switch coupled between drains of the cross-coupled transistor pair and the differential output.
The CML circuit of 10, wherein the differential transistor pair comprises a pair of n-channel transistors having respective drains coupled to the differential output port, respective gates coupled to the differential input port, and respective sources coupled to the bias port.
A method of operating a current-mode logic (CML) circuit having a differential transistor pair coupled to a load circuit configured for inductive broadbanding, the method comprising:
- coupling a differential input signal to a differential input port of a differential transistor pair;
- controlling a switch to couple a cross-coupled transistor pair of the load circuit to a differential output port of the differential transistor pair, sources of the cross-coupled transistor pair being directly coupled to a supply voltage;
- and
- receiving a differential output signal from the differential output port of the differential transistor pair.
Dependencies are inferred from the claim text.