General description

The HEF4021B is an 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 V to 15 V referenced to VSS (usually ground). Unused inputs must be connected to VDD, VSS, or another input. It is also suitable for use over both the industrial (−40 °C to +85 °C) and automotive (−40 °C to +125 °C) temperature ranges.

Features

■ Tolerant of slower rise and fall times

■ Fully static operation

■ 5 V, 10 V, and 15 V parametric ratings

■ Standardized symmetrical output characteristics

■ Operates across the automotive temperature range −40 °C to +125 °C

■ Complies with JEDEC standard JESD 13-B

■ ESD protection:

   ◆ HBM JESD22-A114E exceeds 2000 V

   ◆ MM JESD22-A115-A exceeds 200 V

Applications

■ Industrial and automotive