TH71221_15 Datasheet, PDF (25/44 Pages) Melexis Microelectronic Systems – FSK/FM/ASK Transceiver

5.1.5 D – word
TH71221
27 to 930MHz
FSK/FM/ASK Transceiver
Name
NT
ERTM
LDTM
MODCTRL
Bits
[16:0]
[18:17]
[20:19]
[21]
Description
Feedback divider ratio in TX operation mode
64d .. 131071d
Set the unlock condition of the PLL
00 2 clocks _#default
01 4 clocks
10 8 clocks
Set the maximum allowed number of reference clocks
(1/fRO) during the phase detector output signals (UP &
DOWN) can be in-consecutive.
11 16 clocks
Set the lock condition of the PLL
00 4 clocks
01 16 clocks _#default
10 64 clocks
11 256 clocks
Set the minimum number of consecutive edges of phase
detector output cycles, without appearance of any unlock
condition.
Set mode of modulation control:
0 external modulation control
#default
Modulation will be set via pin ASK/FSK.
1 internal modulation control
Modulation will be set via bit MODSEL (bit 19 in A-word). Nevertheless pin ASK/FSK must be
connected to either VCC or VEE.
39010 071221
Rev. 009
Page 25 of 44
Data Sheet
Nov/15