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AS3977

Data Sheet - C o n t e n t s

Contents

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

2 Key Features............................................................................................................................................................................. 1

3 Applications............................................................................................................................................................................... 1

4 Pin Assignments ....................................................................................................................................................................... 5

4.1 Pin Descriptions.................................................................................................................................................................................... 5

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

7

6 Electrical Characteristics...........................................................................................................................................................

8

7 Timing Characteristics ............................................................................................................................................................

15

7.1 Timing Parameters ............................................................................................................................................................................. 16

8 Detailed System Description...................................................................................................................................................

17

8.1 Reference Frequency Generator........................................................................................................................................................ 17

8.2 Phase Locked Loop............................................................................................................................................................................ 17

8.3 Gaussian Filter and Digital Modulator ................................................................................................................................................ 17

8.4 Power Amplifier .................................................................................................................................................................................. 17

8.5 Temperature Sensor........................................................................................................................................................................... 17

8.6 Low Power Reset ............................................................................................................................................................................... 17

8.7 Low Drop Out Regulators................................................................................................................................................................... 17

8.8 SDI / Control Interface........................................................................................................................................................................ 18

8.9 Baud Rate Generator ......................................................................................................................................................................... 18

9 Application Information ...........................................................................................................................................................

19

9.1 Operation Modes................................................................................................................................................................................ 19

9.2 Transmitter Control Interface.............................................................................................................................................................. 20

9.2.1 Configuration Diagram............................................................................................................................................................... 21

9.2.2 Power On Reset ........................................................................................................................................................................ 22

9.2.3 Writing of Data to Addressable Registers.................................................................................................................................. 22

9.2.4 Reading of Data from Addressable Registers ........................................................................................................................... 23

9.2.5 Transmitting Data ...................................................................................................................................................................... 25

9.3 Transmitter Control States.................................................................................................................................................................. 25

9.3.1 Power Down State..................................................................................................................................................................... 25

9.3.2 Active Edge of CLK.................................................................................................................................................................... 26

9.3.3 Active State................................................................................................................................................................................ 26

9.3.4 Transmit State ........................................................................................................................................................................... 26

9.4 ENABLE Signal Functionality ............................................................................................................................................................. 27

9.5 Communication and Command Byte Structure .................................................................................................................................. 28

9.6 Transmitter Configuration Register..................................................................................................................................................... 29

9.7 Special Bits......................................................................................................................................................................................... 33

9.7.1 LT (Lock Transmit)..................................................................................................................................................................... 33

9.7.2 LS (Low Power Supply Voltage)................................................................................................................................................ 33

9.7.3 MCCS, CLKS and PSC ............................................................................................................................................................. 33

9.7.4 SETPD (Set Power Down)......................................................................................................................................................... 33

9.8 Output Frequency Setting................................................................................................................................................................... 34

9.8.1 Implementation .......................................................................................................................................................................... 35

9.8.2 Optional Frequency Calculation with Overlapping Fractional Bands by Using the Bit INT<8>.................................................. 36

9.8.3 FSK Deviation Setting and Frequency Trimming....................................................................................................................... 37

9.9 Baud Rate Generator ......................................................................................................................................................................... 38