The 74HC74 is a dual positive edge triggered D-type flip-flop. They have individual data (nD), clock (nCP), set (nSD) and reset (nRD) inputs, and complementary nQ and nQ outputs. Data at the nD-input, that meets the set-up and hold time requirements on the LOW-to-HIGH clock transition, is stored in the flip-flop and appears at the nQ output. Schmitt-trigger action in the clock input, makes the circuit highly tolerant to slower clock rise and fall times. Inputs include clamp diodes that enable the use of current limiting resistors to interface inputs to voltages in excess of VCC.
description/ordering information The ’HC74 devices contain two independent D-type positive-edge-triggered flip-flops. A low level at the preset (PRE) or clear (CLR) inputs sets or resets the outputs, regardless of the levels of the other inputs. When PREand CLRare inactive (high), data at the data (D) input meeting the setup time requirements are transferred to the outputs on the positive-going edge of the clock (CLK) pulse. Clock triggering occurs at a voltage level and is not directly related to the rise time of CLK. Following the hold-time interval, data at the D input can be changed without affecting the levels at the outputs. Wide Operating Voltage Range of 2 V to 6 V Outputs Can Drive Up To 10 LSTTL Loads Low Power Consumption, 40-µA Max ICC Typical tpd = 15 ns ±4-mA Output Drive at 5 V Low Input Current of 1 µA Max
The 74HC74D is a dual positive edge triggered D-type Flip-flop has individual data (nD), clock (nCP), set (nSD\\) and reset (nRD\\) inputs and complementary nQ and nQ outputs. Data at the nD-input, that meets the set-up and hold time requirements on the low-to-high clock transition, is stored in the flip-flop and appears at the nQ output. Schmitt-trigger action in the clock input, makes the circuit highly tolerant to slower clock rise and fall times. Inputs include clamp diodes that enable the use of current limiting resistors to interface inputs to voltages in excess of VCC.