AN501

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Contents

Contents ....................................................................................................................................................... 2

1 Introduction ........................................................................................................................................... 3

1.1 Target audience ............................................................................................................................ 3

2 VCC Ramp and the Importance of Correct Power-up Sequencing .................................................. 4

2.1 The importance of correctly loading configuration settings during power-up ............................... 6

2.2 Consequences of Incorrect Power-up Sequencing ...................................................................... 7

2.3 Power-up sequencing in the datasheet ........................................................................................ 7

2.3.1 Power-Up Timing Example 1......................................................................................... 7

2.3.2 Power-Up Timing Example 2......................................................................................... 9

2.4 Examples of good and bad VCC ramps ..................................................................................... 10

3 Reset .................................................................................................................................................... 12

3.1 Hardware Reset .......................................................................................................................... 12

3.2 JEDEC Reset .............................................................................................................................. 13

3.3 Software Reset ........................................................................................................................... 13

4 Brown-out ............................................................................................................................................ 14

4.1 Causes of brown-out conditions ................................................................................................. 14

4.2 Recovery from a brown-out condition ......................................................................................... 15

4.3 Avoiding a brown-out condition .................................................................................................. 15

5 Power-Down ........................................................................................................................................ 16

6 Power Cycling and Power Saving Modes ......................................................................................... 17

6.1 Power Cycling (Power-Off Followed by a Power-On) ................................................................ 17

6.2 Entering and Exiting Ultra-Deep Power-Down (uDPD) .............................................................. 17

Appendix A ................................................................................................................................................ 19

a) JEDEC Reset (JEDEC Standard #: JESD252) .......................................................................... 19

b) ABh Command ........................................................................................................................... 20

c) Device Resets ............................................................................................................................. 20

d) Enable Reset (66h) and Reset (99h) Commands ...................................................................... 20

List of Figures ........................................................................................................................................... 21

Revision History ........................................................................................................................................ 22