NXP HEF4021BT,653 移位寄存器, 并行至并行、串行至并行, 1元件, SOIC, 16 引脚, 3 V, 15 V
The HEF4021BT is a 8-bit static Shift Register parallel-to-serial converter with a synchronous serial data input DS, a clock input CP, an asynchronous active high parallel load input PL, eight asynchronous parallel data inputs D0 to D7 and buffered parallel outputs from the last three stages Q5 to Q7. Each register stage is a D-type master-slave flip-flop with a set direct SD and clear direct CD input. Information on D0 to D7 is asynchronously loaded into the register while PL is high, independent of CP and DS. When PL is low, data on DS is shifted into the first register position and all the data in the register is shifted one position to the right on the low-to-high transition of CP. Schmitt trigger action makes the clock input highly tolerant of slower rise and fall times. It operates over a recommended VDD power supply range of 3 to 15V referenced to VSS usually ground. Unused inputs must be connected to VDD, VSS or another input.