CD4021BE | Texas Instruments

Stage Static Shift Register, CD4021BE, Texas Instruments

The CD4021BE type is an 8-stage parallel- or serial-input/serial-output register having a common CLOCK and PARALLEL/SERIAL CONTROL input, a single SERIAL data input, and individual parallel "JAM" inputs to each register stage. Each register stage is a D-type, master-slave flip-flop. Parallel as well as serial entry is made into the register synchronously with the positive clock line transition in the CD4021BE. In the CD4021BE, serial entry is synchronous with the clock, but parallel entry is asynchronous. In both types, entry is controlled by the PARALLEL/SERIAL CONTROL input.

When the PARALLEL/SERIAL CONTROL input is low, data is serially shifted into the 8-stage register synchronously with the positive transition of the clock line. When the PARALLEL/SERIAL CONTROL input is high, data is jammed into the 8-stage register via the parallel input lines and synchronously with the positive transition of the clock line. In the CD4021B, the CLOCK input of the internal stage is "forced" when asynchronous parallel entry is made. Register expansion using multiple packages is permitted.

Features

• Fully static operation
• 8 master-slave flip-flops plus output buffering and control gating
• Standardized, symmetrical output characteristics

Applications

• Parallel input/serial output data queueing
• Parallel to serial data conversion
• General-purpose register