TH7122 Datasheet, PDF (2/44 Pages) Melexis Microelectronic Systems – 27 to 930MHz FSK/FM/ASK Transceiver

TH7122
27 to 930MHz
FSK/FM/ASK Transceiver
Document Content
1 Theory of Operation ...................................................................................................4
1.1 General............................................................................................................................. 4
1.2 Technical Data Overview.................................................................................................. 4
1.3 Note on ASK Modulation .................................................................................................. 4
1.4 Block Diagram .................................................................................................................. 5
1.5 User Mode Features ......................................................................................................... 5
2 Pin Definitions and Descriptions ..............................................................................6
3 Functional Description ............................................................................................10
3.1 PLL Frequency Synthesizer ........................................................................................... 10
3.1.1 Reference Oscillator (XOSC)..................................................................................................... 11
3.1.2 Reference Divider ...................................................................................................................... 11
3.1.3 Feedback Divider ....................................................................................................................... 11
3.1.4 Frequency Resolution and Operating Frequency ...................................................................... 11
3.1.5 Phase-Frequency Detector ........................................................................................................ 12
3.1.6 Lock Detector............................................................................................................................. 12
3.1.7 Voltage Controlled Oscillator with external Loop Filter.............................................................. 13
3.1.8 Loop Filter .................................................................................................................................. 13
3.2 Receiver Part.................................................................................................................. 13
3.2.1 LNA ............................................................................................................................................ 14
3.2.2 Mixer .......................................................................................................................................... 14
3.2.3 IF Amplifier ................................................................................................................................. 14
3.2.4 ASK Demodulator ...................................................................................................................... 14
3.2.5 FSK Demodulator ...................................................................................................................... 15
3.3 Transmitter Part .............................................................................................................. 15
3.3.1 Power Amplifier.......................................................................................................................... 15
3.3.2 Output Power Adjustment .......................................................................................................... 16
3.3.3 Modulation Schemes ................................................................................................................. 16
3.3.4 ASK Modulation ......................................................................................................................... 16
3.3.5 FSK Modulation ......................................................................................................................... 17
3.3.6 Crystal Tuning............................................................................................................................ 17
4 Description of User Modes......................................................................................18
4.1 Stand-alone User Mode Operation ................................................................................. 18
4.1.1 Frequency Selection .................................................................................................................. 18
4.1.2 Operation Mode ......................................................................................................................... 18
4.1.3 Modulation Type ........................................................................................................................ 19
4.1.4 LNA Gain Mode ......................................................................................................................... 19
4.2 Programmable User Mode Operation............................................................................. 19
4.2.1 Serial Control Interface Description ........................................................................................... 19
5 Register Description ................................................................................................20
5.1 Register Overview .......................................................................................................... 21
39010 07122
Rev. 008
Page 2 of 44
Data Sheet
June/07