NXP 逻辑集成电路移位寄存器 74HC165D

74HC165D

FEATURES

• Asynchronous 8-bit parallel load

• Synchronous serial input

• Output capability: standard

• ICC category: MSI

74HC165D

GENERAL DESCRIPTION

The 74HC/HCT165 are high-speed Si-gate CMOS devices

and are pin compatible with low power Schottky TTL

(LSTTL). They are specified in compliance with JEDEC

standard no. 7A.

The 74HC/HCT165 are 8-bit parallel-load or serial-in shift

registers with complementary serial outputs (Q7 and

Q7) available from the last stage. When the parallel load

(PL) input is LOW, parallel data from the D0 to

D7 inputs are loaded into the register asynchronously.

When PL is HIGH, data enters the register serially at the

Ds input and shifts one place to the right

(Q0 → Q1 → Q2, etc.) with each positive-going clock

transition. This feature allows parallel-to-serial converter

expansion by tying the Q7 output to the DS input of 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.

The pin assignment for the CP and CE inputs is arbitrary

and can be reversed for layout convenience. The

LOW-to-HIGH transition of input CE should only take

place while CP HIGH for predictable operation. Either the

CP or the CE should be HIGH before the

LOW-to-HIGH transition of PL to prevent shifting the data

when PL is activated.

APPLICATIONS

• Parallel-to-serial data conversion

74HC165D