General Description

The MM74C165 functions as an 8-bit parallel-load, serial shift register. Data is loaded into the register independent of the state of the clock(s) when PARALLEL LOAD (PL) is low. Shifting is inhibited as long as PL is low. Data is sequentially shifted from complementary outputs, Q7 and Q7, highest-order bit (P7) first. New serial data may be entered via the SERIAL DATA (Ds) input. Serial shifting occurs on the rising edge of CLOCK1 or CLOCK2. Clock inputs may be used separately or together for combined clocking from independent sources. Either clock input may be used also as an active-low clock enable. To prevent double-clocking when a clock input is used as an enable, the enable must be changed to a high level (disabled) only while the clock is HIGH.

特性 Features

■ Wide supply voltage range: 3V to 15V

■ Guaranteed noise margin: 1V

■ High noise immunity: 0.45 VCC (typ.)

■ Low power TTL compatibility: fan out of 2 driving 74L

■ Parallel loading independent of clock

■ Dual clock inputs

■ Fully static operation