RF Quadrature Transceiver / RF Quadrature Receiver
CMX991/CMX992
C1 1nF
C2 15pF
C3a 3.9pF
C3b 4.7pF
C4 4.7pF
C5 1nF
C7 1nF
C8 18pF
L1 1µH
L2 1µH
R1 1200Ω
R2 220Ω
F1 45G15B1
Table 5 1st IF Filtering Components for 45MHz
4.2.3 Rx Output
4.2.3.1 I/Q Output Amplifiers
The CMX991/CMX992 includes uncommitted differential amplifiers, which may be used to convert the
differential I and Q output signals to a single ended output. A typical configuration of the amplifier on the Q
channel (the I channel is identical) is shown in Figure 8. This circuit has a linear gain of 1.5 and is not
optimum for rejection of common mode signals, however in practice performance is generally satisfactory.
Users should note that the gain and bandwidth of this stage can be adjusted by altering the component
values and should be configured to suite a particular application.
C1
R1
QAMPP
Pin 21
RXQN
Pin19
QAMPO
Pin 23
QAMP
R2
QAMPN
Pin 22
RXQP
Pin 20
R3
C2
Figure 8 Example External Components – Receive I/Q Output
C1 NF
C2 NF
R1 10kΩ
R2 10kΩ
R3 10kΩ
Table 6 Rx I/Q Differential to Single Ended Amplifier Components
2012 CML Microsystems Plc
13
D/991_992/18
CMLMICRO [ CML MICROCIRCUITS ]
