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AS3931

Datasheet - Contents

Contents

1 General Description .................................................................................................................................................................. 1

2 Key Features

............................................................................................................................................................................ 1

3 Applications

.............................................................................................................................................................................. 1

4 Pin Assignments ....................................................................................................................................................................... 4

4.1 Pin Descriptions

...................................................................................................................................................................................4

5 Absolute Maximum Ratings ...................................................................................................................................................... 5

6 Electrical Characteristics

.......................................................................................................................................................... 6

7 Typical Operating Characteristics ............................................................................................................................................. 9

7.1 RSSI Characteristic ..............................................................................................................................................................................9

7.2 Temperature Dependence of RSSI

....................................................................................................................................................10

7.3 Supply Voltage Dependence of RSSI

................................................................................................................................................ 11

7.4 Frequency Dependence of RSSI

....................................................................................................................................................... 12

8 Detailed Description

............................................................................................................................................................... 13

8.1 Block Diagram .................................................................................................................................................................................... 13

8.2 Block Description

............................................................................................................................................................................... 13

8.2.1 Antenna Rotator ......................................................................................................................................................................... 13

8.2.2 Input Attenuator ......................................................................................................................................................................... 13

8.2.3 Input Shortcutting ....................................................................................................................................................................... 13

8.2.4 Input Protection Circuit .............................................................................................................................................................. 13

8.2.5 Logarithmic Envelope Amplifiers ............................................................................................................................................... 14

8.2.6 Detectors ................................................................................................................................................................................... 14

8.2.7 Digital Correlators ...................................................................................................................................................................... 14

8.2.8 Wake Generator ........................................................................................................................................................................ 14

8.2.9 Crystal Oscillator ........................................................................................................................................................................ 14

8.2.10 Regulator ................................................................................................................................................................................. 14

8.2.11 Power On Reset (POR) ........................................................................................................................................................... 14

8.3 Basic Operation .................................................................................................................................................................................. 15

8.3.1 LF Transmission Protocol .......................................................................................................................................................... 15

8.3.2 Wake Up Detection .................................................................................................................................................................... 16

8.3.3 WAKE Signal Clearing ............................................................................................................................................................... 16

8.3.4 WAKE Signal After POR ............................................................................................................................................................ 16

8.3.5 RSSI Operation .......................................................................................................................................................................... 16

8.4 Serial Programming Interface Timing ................................................................................................................................................. 16

8.5 Input Signal Waveform Definition ....................................................................................................................................................... 17

9 Configuring the Product .......................................................................................................................................................... 18

9.1 Serial Programming Interface

............................................................................................................................................................ 18

9.2 Power On Register ............................................................................................................................................................................. 18

9.2.1 P0, P1, P2 (Channel Enable) ..................................................................................................................................................... 19

9.2.2 P3 (Regulator Enable) ............................................................................................................................................................... 19

9.2.3 P4, P5 (Antenna Rotator/Input Shortcut) ................................................................................................................................... 19

9.3 RSSI Channel Select Register ........................................................................................................................................................... 19

9.3.1 C0, C1 (RSSI Channel Select) .................................................................................................................................................. 20

9.3.2 C2, C3 (RSSI Output Mode) ...................................................................................................................................................... 20

9.3.3 C4 (Channel Attenuator) ............................................................................................................................................................ 20

9.3.4 C5 (WAKE Clear) ....................................................................................................................................................................... 21