HEF4021BT,652

Shift Registers Overview

The HEF4021BT,652 is an 8-bit static shift register (parallel-to-serial converter) manufactured by Nexperia. It features a synchronous serial data input (DS), a clock input (CP), and an asynchronous active HIGH parallel load input (PL). The device includes eight asynchronous parallel data inputs (D0 to D7) and buffered parallel outputs from the last three stages (Q5 to Q7). Each stage utilizes a D-type master-slave flip-flop with set direct (SD) and clear direct (CD) inputs. It operates within a recommended VDD power supply range of 3 V to 15 V referenced to VSS.

Shift Registers Feature Summary

• Schmitt trigger action on the clock input provides high tolerance for slower rise and fall times.
• Fully static operation ensures reliable performance across the specified voltage range.
• ESD protection exceeds 2000 V according to HBM standards and 1000 V according to CDM standards.

Shift Registers Applications

• Parallel-to-serial data conversion
• Serial-to-parallel data conversion
• Digital signal processing

Shift Registers Procurement Notes

Verify the specific ordering suffix against the manufacturer's current documentation to confirm package type and temperature range. Confirm RoHS compliance status directly with the supplier or official datasheet before procurement. Ensure design-in requirements match the SO16 package specifications provided in the product data sheet.

Shift Registers Selection Notes

Select this component when an 8-bit shift register with buffered parallel outputs is required. Verify that the operating environment falls within the -40 °C to +125 °C temperature range. Ensure the application logic levels are compatible with the 3 V to 15 V supply voltage range. Check pinout compatibility if replacing existing designs.

Shift Registers Part Context

This part belongs to the HEF4021B series of 8-bit static shift registers. The 'BT' designation indicates the SO16 plastic small outline package variant. The ',652' suffix typically denotes specific packaging details such as tube quantity, which should be verified in the latest ordering information section of the datasheet.

Shift Registers Replacement Considerations

HEF4021BTT,653

Shift Registers FAQ

How does the parallel load function operate?

Information on D0 to D7 is asynchronously loaded into the register while the PL input is HIGH, independent of the CP and DS signals.

What happens when the parallel load input is LOW?

When PL is LOW, data on the DS input is shifted into the first register position, and all data in the register shifts one position to the right on the LOW-to-HIGH transition of CP.