TRF6900
SINGLE-CHIP RF TRANSCEIVER
SLAS213C – SEPTEMBER 1999 – REVISED MAY 2000
PRINCIPLES OF OPERATION
Table 2. Mode1 Control Register Description (C-Word)
INITIAL SETTINGS
AFTER POWER-UP
BIT
NUMBER
SYMBOL
DESCRIPTION
LOCATION OF BITS
DEFAULT
STATE
DEFAULT
VALUE
1_LNAM
[1:0]
Low-noise amplifier operation mode
Disabled
00b
L1
0
0
L0
0
1
: LNA disabled
: LNA enable – low-gain mode
: LNA disabled
2
1
0
1
1
: LNA enable – normal operation mode
1_MIX
1_IF
[2]
[3]
[4]
[5]
[6]
1
1
1
1
Enable mixer
1: enabled
1: enabled
1: enabled
1: enabled
0: disabled
0: disabled
0: disabled
0: disabled
Disabled
Disabled
Disabled
Disabled
0b
0b
0b
0b
0b
st
Enable 1 IF amplifier
1_LIM
1_RSSI
1_SW
Enable limiter
Enable RSSI
Data switch
Routed to
Demodulator
1
0 : LPF amplifier input routed to demodulator (FSK/FM)
1 : LPF amplifier input routed to RSSI (OOK/ASK)
1_LPF
1_SLC
1_PA
[7]
[8]
1
1
Enable LPF amplifier
Enable data slicer
1: enabled
1: enabled
0: disabled
0: disabled
Disabled
Disabled
Disabled
0b
0b
[10:9]
Power amplifier mode
00b
P1
0
0
1
1
P0
0
1
0
1
: disabled
2
: 10 dB attenuation, enable modulation via TX_DATA
: 20 dB attenuation, enable modulation via TX_DATA
: 0 dB attenuation, enable modulation via TX_DATA
1_VCO
1_PLL
[11]
[12]
During operation, this bit should always be enabled (1: enabled), unless
an external VCO is used.
Disabled
Disabled
0b
0b
1
1
Enable PLL (DDS system, VCO, RF divider, phase comparator and charge
pump)
1: enabled
0: disabled
NOTE: The FM/FSK demodulator is automatically enabled if the limiter and low-pass amplifier are enabled and the data switch is set to FSK
reception.
25
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TI [ TEXAS INSTRUMENTS ]
