SN74HC273NSR

The SN74HC273NSR from Texas Instruments contains eight positive-edge-triggered D-type flip-flops with a direct active-low clear (CLR) input. Data at the D inputs meeting the setup time requirements is transferred to the Q outputs on the positive-going edge of the clock (CLK) pulse. Clock triggering occurs at a particular voltage level and is not directly related to the transition time of the positive-going pulse. When CLK is at either high or low level, the D input has no effect on the output. The asynchronous CLR input, when asserted LOW, overrides the clock and forces all Q outputs LOW regardless of the D input states. The device operates over a wide voltage range of 2 V to 6 V with typical propagation delay of 12 ns, making it suitable for a wide variety of data storage and register applications.

The SN74HC273NSR contains eight independent D-type flip-flops sharing common clock (CLK) and clear (CLR) signals. Each flip-flop consists of a master-slave latch structure controlled by the clock edge. On the rising edge of CLK, the data present at each D input is captured and transferred to the corresponding Q output. The setup time requirement specifies the minimum time that data must be stable before the clock edge; the hold time specifies the minimum time data must remain stable after the clock edge. The asynchronous CLR input, when driven LOW, forces all Q outputs LOW immediately, overriding any clock or data input activity. The output stages use push-pull (totem-pole) CMOS drivers capable of sourcing or sinking up to 5.2 mA while maintaining valid logic levels. The internal CMOS structure provides very low static power consumption of 80 µA maximum.

• Address latching: Capturing and holding address data from a multiplexed address/data bus in microprocessor systems
• Output registers: Holding output data stable in bus-oriented designs while the source changes
• Data synchronization: Capturing asynchronous input data on a clock edge to eliminate metastability
• State machines: Storing the current state vector in sequential logic designs
• Pipeline registers: Inter-stage data storage in digital signal processing pipelines