Table of Contents

1 Features............................................................................1

2 Applications..................................................................... 1

3 Description.......................................................................1

4 Revision History.............................................................. 2

5 Pin Configuration and Functions...................................3

Pin Functions.................................................................... 3

6 Specifications.................................................................. 4

6.1 Absolute Maximum Ratings........................................ 4

6.2 Recommended Operating Conditions.........................4

6.3 Thermal Information....................................................4

6.4 Electrical Characteristics - 74..................................... 5

6.5 Electrical Characteristics - 54..................................... 5

6.6 Switching Characteristics - 74.....................................6

6.7 Switching Characteristics - 54.....................................6

6.8 Operating Characteristics........................................... 6

6.9 Typical Characteristics................................................ 6

7 Parameter Measurement Information............................ 8

8 Detailed Description........................................................9

8.1 Overview..................................................................... 9

8.2 Functional Block Diagram........................................... 9

8.3 Feature Description.....................................................9

8.4 Device Functional Modes..........................................10

9 Application and Implementation.................................. 11

9.1 Application Information..............................................11

9.2 Typical Application.................................................... 11

10 Power Supply Recommendations..............................13

11 Layout........................................................................... 14

11.1 Layout Guidelines................................................... 14

11.2 Layout Example...................................................... 14

12 Device and Documentation Support..........................15

12.1 Documentation Support.......................................... 15

12.2 Support Resources................................................. 15

12.3 Trademarks.............................................................15

12.4 Electrostatic Discharge Caution..............................15

12.5 Glossary..................................................................15

13 Mechanical, Packaging, and Orderable

Information.................................................................... 15

4 Revision History

NOTE: Page numbers for previous revisions may differ from page numbers in the current version.

Changes from Revision E (August 2003) to Revision F (June 2021)

Page

• Updated to new data sheet standards................................................................................................................ 1

SN74HC21, SN54HC21

SCLS087F – DECEMBER 1982 – REVISED JUNE 2021

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