Shift Register Single 8-Bit Serial/Parallel to Serial 16-Pin SOIC T/R

The ’HC166 and ’HCT166 8-bit shift register is fabricated with silicon gate CMOS technology. It possesses thelow power consumption of standard CMOS integrated circuits, and can operate at speeds comparable to the equivalent low powerSchottky device. The ’HCT166 is functionally and pin compatible with the standard ’LS166. The 166 is an 8-bit shift register that has fully synchronous serial or parallel data entry selected by an active LOWParallel Enable (PE\) input. When the PE\ is LOW one setup time before the LOW-to-HIGH clock transition, parallel data isentered into the register. When PE\ is HIGH, data is entered into the internal bit position Q0 from Serial Data Input (DS),and the remaining bits are shifted one place to the right (Q0 ? Q1 ? Q2, etc.) with each positive-going clocktransition. For expansion of the register in parallel to serial converters, the Q7 output is connected to the DS inputof the succeeding stage. The clock input is a gated OR structure which allows one input to be used as an active LOW Clock Enable (CE\) input. Thepin assignment for the CP and CE\ inputs is arbitrary and can be reversed for layout convenience. The LOW-to-HIGH transitionof CE\ input should only take place while the CP is HIGH for predictable operation. A LOW on the Master Reset (MR\) input overrides all other inputs and clears the register asynchronously, forcing allbit positions to a LOW state.

Buffered Inputs

Fanout (Over Temperature Range)

• Standard Outputs...10 LSTTL Loads
• Bus Driver Outputs...15 LSTTL Loads

Wide Operating Temperature Range . . . -55°C to 125°C

Balanced Propagation Delay and Transition Times

Significant Power Reduction Compared to LSTTL Logic ICs

HC Types

• 2V to 6V Operation
• High Noise Immunity: N_IL = 30%, N_IH = 30% of V_CC at V_CC = 5V

HCT Types

• 4.5V to 5.5V Operation
• Direct LSTTL Input Logic Compatibility, V_IL = 0.8V (Max), V_IH = 2V (Min)