Fast flip-flop structure with reduced set-up time

A flip-flop, comprising:

• a first master latch adapted to receive a function data through a first switch, the first switch adapted to be controlled by a clock signal;
• a second master latch adapted to receive a scan data through a second switch, the second switch adapted to be controlled by the clock signal;
• and
• a slave latch connected to the first master latch through a third switch, the third switch adapted to be controlled by the clock signal;
• wherein the second master latch is coupled to the first master latch through a fourth switch adapted to be controlled by a scan enable signal so that the flip-flop is adapted to control whether the function data or the scan data becomes an output from the first master latch to the slave latch based on the scan enable signal, and the slave latch is adapted to latch and transmit the output from the first master latch.

A flip-flop, comprising:

• a first master latch adapted to receive a function data through a first switch, the first switch adapted to be controlled by a clock signal;
• a second master latch adapted to receive a scan data through a second switch, the second switch adapted to be controlled by the clock signal;
• and
• a slave latch connected to the first master latch through a third switch, the third switch adapted to be controlled by the clock signal;
• wherein the second master latch is coupled to the first master latch through a fourth switch adapted to be controlled by a scan enable signal so that the flip-flop is adapted to control whether the function data or the scan data becomes an output from the first master latch to the slave latch based on the scan enable signal, the slave latch is adapted to latch and transmit the output from the first master latch, and the scan enable signal adapted to change at a high phase of the clock signal.