
5-98
RF9958
Rev B11 010720
5
M
U
Pin
22
23
24
Function
MIX IN+
GND2
MOD OUT-
Description
Same as pin 21, except complementary input.
Interface Schematic
See pin 21.
Same as pin 16.
One half of the balanced AGC output port. The impedance of this port
is 200
 balanced. If no filtering is required, this pin can be connected
to the MIX IN- pin through a DC blocking capacitor. This pin requires an
inductor to V
CC
to achieve full dynamic range. In order to maximize
gain, this inductor should be a high-Q type and should be parallel reso-
nated out with a capacitor (see application schematic). This pin is NOT
DC blocked. A blocking capacitor of 2200pF is needed when this pin is
connected to a DC path. An appropriate matching network may be
needed if an IF filter is used.
25
26
MOD OUT+
DEC
Same as pin 24, except complementary output.
See pin 24.
AGC decoupling pin. An external bypass capacitor of 10nF capacitor is
required. The trace length between the pin and the bypass capacitors
should be minimized. The ground side of the bypass capacitors should
connect immediately to ground plane.
Analog gain control for AGC amplifiers. Valid control voltage ranges are
from 0.5V
DC
to 2.5V
DC
. The gain range for the AGC is 88dB. These
voltages are valid ONLY for a 37k
 source impedance. A DC voltage
less than or equal to the maximum allowable Vcc may be applied to this
pin when no voltage is applied to the Vcc pins.
27
GC
28
VCC2
Supply for the modulator stage only. A 10nF external bypass capacitor
is required and an additional 0.1
μ
F will be required if no other low fre-
quency bypass capacitors are nearby. The trace length between the pin
and the bypass capacitors should be minimized. The ground side of the
bypass capacitors should connect immediately to ground plane.
100
 
100
 
MOD OUT-
MOD OUT+
V
CC3
V
CC3
21 k
GC
40 k
BIAS