TRF6900
SINGLE-CHIP RF TRANSCEIVER
SLAS213C – SEPTEMBER 1999 – REVISED MAY 2000
st
1
IF amplifier (continued)
↑1
U
↑1 U
CH1 S11
CH1 S22
1
1
PRN
0.5
2
0.5
2
5
5
CAL
OFS
CAL
OFS
0
0.2
0.5
1
2
5
10
0
0.2
0.5
1
2
5
10
CPL
CPL
–5
–5
FIL
1k
FIL
1k
–0.5
–0.5
–2
–2
–1
–1
START 5 MHz
STOP 25 MHz
START 5 MHz
STOP 25 MHz
st
st
Figure 8. Typical 1 IF Amplifier Input
Impedance (S11) at Device Terminal IF1_IN
Figure 9. Typical 1 IF Amplifier Output
Impedance (S22) at Device Terminal IF1_OUT
nd
2
IF amplifier/limiter
nd
The 2 IF amplifier/limiter consists of several differential amplifier stages with an overall gain of approximately
80 dB. At the IF2_IN 330 Ω input, a minimum signal level of approximately 32 µV is required to generate a limited
signal at the limiter output. The limiter output is directly fed to the FM/FSK demodulator.
nd
Figure 10 shows the 2 IF amplifier/limiter input impedance.
↑1
U
CH1 S11
1
0.5
2
5
CAL
OFS
0
0.2
0.5
1
2
5
10
CPL
–5
FIL
1k
–0.5
–2
–1
START 5 MHz
STOP 25 MHz
nd
Figure 10. Typical 2 IF Amplifier/Limiter Input
Impedance (S11) at Device Terminal IF2_IN
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TI [ TEXAS INSTRUMENTS ]
