TH7122 Datasheet, PDF (18/44 Pages) Melexis Microelectronic Systems – 27 to 930MHz FSK/FM/ASK Transceiver

TH7122
27 to 930MHz
FSK/FM/ASK Transceiver
4 Description of User Modes
4.1 Stand-alone User Mode Operation
After power up the transceiver is set to stand-alone user mode. In this mode, pins FS0/SDEN and FS1/LD
must be connected to V_EE or V_CC to set the desired frequency of operation. The logic level at pin FS0/SDEN
must not be changed after power up in order to remain in stand-alone user mode. The default settings of the
control word bits in stand-alone user mode are described in the frequency selection table. Detailed informa-
tion about the default settings can be found in the tables of section 5.
4.1.1 Frequency Selection
Channel frequency
FS0/SDEN
FS1/LD
Reference oscillator frequency
R counter ratio in RX mode (RR)
PFD frequency in RX mode
N counter ratio in RX mode (NR)
VCO frequency in RX mode
RX frequency
R counter ratio in TX mode (RT)
PFD frequency in TX mode
N counter ratio in TX mode (NT)
VCO frequency in TX mode
TX frequency
IF in RX mode
433.92 MHz
1
0
32
223.45 kHz
1894
423.22 MHz
433.92 MHz
32
223.45 kHz
1942
433.92 MHz
433.92 MHz
10.7 MHz
868.3 MHz
0
0
315 MHz
1
1
7.1505 MHz
16
18
446.91 kHz 397.25 kHz
1919
766
857.60 MHz 304.30 MHz
868.30 MHz 315.00 MHz
16
18
446.91 kHz 397.25 kHz
1943
793
868.30 MHz 315.00 MHz
868.30 MHz 315.00 MHz
10.7 MHz
10.7 MHz
915 MHz
0
1
32
223.45 kHz
4047
904.30 MHz
915.00 MHz
32
223.45 kHz
4095
915.00 MHz
915.00 MHz
10.7 MHz
In stand-alone user mode, the transceiver can be set to Standby, Receive, Transmit or Idle mode (only PLL
synthesizer active) via control pins RE/SCLK and TE/SDTA. The modulation scheme and the LNA gain are
set by pins ASK/FSK and GAIN_LNA, respectively.
4.1.2 Operation Mode
Operation mode
Standby
Receive
Transmit
Idle
RE/SCLK
0
1
0
1
TE/SDTA
0
0
1
1
Note: Pins with internal pull-down
39010 07122
Rev. 008
Page 18 of 44
Data Sheet
June/07