Description
The ’HC194 and CD74HCT194 are 4-bit shift registers with Asynchronous Master Reset (MR). In the parallel mode (S0 and S1 are high), data is loaded into the associated flip-flop and appears at the output after the positive transition of the clock input (CP). During parallel loading serial data flow is inhibited. Shift left and shift right are accomplished synchronously on the positive clock edge with serial data entered at the shift left (DSL) serial input for the shift left mode, and at the shift right (DSR) serial input for the shift right mode. Clearing the register is accomplished by a Low applied to the Master Reset (MR) pin.

FEATUREs
• Four Operating Modes
   - Shift Right, Shift Left, Hold and Reset
• Synchronous Parallel or Serial Operation
• Typical fMAX = 60MHz at VCC = 5V, CL = 15pF, TA = 25°C
• Asynchronous Master Reset
• Fanout (Over Temperature Range)
   - Standard Outputs . . . . . . . . . . . . . . . 10 LSTTL Loads
   - Bus Driver Outputs . . . . . . . . . . . . . 15 LSTTL Loads
• Wide Operating Temperature Range . . . -55oC to 125oC
• Balanced Propagation Delay and Transition Times
• Significant Power Reduction Compared to LSTTL Logic ICs
• HC Types
   - 2V to 6V Operation
   - High Noise Immunity: NIL = 30%, NIH = 30% of VCC at VCC = 5V
• HCT Types
   - 4.5V to 5.5V Operation
   - Direct LSTTL Input Logic Compatibility, VIL= 0.8V (Max), VIH = 2V (Min)
   - CMOS Input Compatibility, Il ≤ 1µA at VOL, VOH