TH7122 Datasheet, PDF (24/44 Pages) Melexis Microelectronic Systems – 27 to 930MHz FSK/FM/ASK Transceiver

TH7122
27 to 930MHz
FSK/FM/ASK Transceiver
5.1.4 C – word
Name
NR
BAND
VCOCUR
Bits
[16:0]
[17]
[19:18]
Description
Feedback divider ratio in RX operation mode
64d .. 131071d
Set the desired frequency range
0 recommended at f_RF < 500 MHz
1 recommended at f_RF > 500MHz
Some tail current sources are linked to this bit in order to save current for low frequency
operations.
VCO active current
00 low current (300 µA)
01 standard current (500 µA)
10 high1 current (700 µA)
11 high2 current (900 µA)
Phase Detector polarity
PFDPOL
LNACTRL
0 ^negative
[20]
#default
1 positive
VCO
pos
OUTPUT
FREQUENCY
neg
VCO INPUT VOLTAGE
LNA gain control mode
0 external LNA gain control
#default
[21]
LNA gain will be set via pin GAIN_LNA.
1 internal LNA gain control
LNA gain will be set via bit LNAGAIN (bit 12 in A-word). Nevertheless pin GAIN_LNA must
be connected to either VCC or VEE.
39010 07122
Rev. 008
Page 24 of 44
Data Sheet
June/07