rf9957 RF Micro Devices, rf9957 Datasheet - Page 3

• Manufacturer Part Number: rf9957
• Description: Cdma/fm Receive Agc And Demodulator
• Manufacturer: RF Micro Devices

Rev C11 010622
Pin
10
11
12
13
1
2
3
4
5
6
7
8
9
CDMA IN+
CDMA IN-
Function
BG OUT
FM IN+
FM IN-
VCC1
VCC2
VCC3
GND
GND
DEC
LO+
LO-
Description
Supply voltage for the LO flip-flop divider and limiting amp. This pin
may be connected in parallel with pins 2 and 3. It should be bypassed
by a 10nF capacitor. The trace length between the pin and the bypass
capacitor should be minimized. The ground side of the bypass capaci-
tor should connect immediately to ground plane. The part is designed
to work from a 2.7V to 3.3V supply.
Supply voltage for the bandgap, gain control bias circuitry, and AGC
stages 2, 3, and 4. This pin may be connected in parallel with pins 1
and 3. It should be bypassed by a 10nF capacitor. The trace length
between the pin and the bypass capacitor should be minimized. The
ground side of the bypass capacitor should connect immediately to
ground plane. The part is designed to work from a 2.7V to 3.3V supply.
Supply voltage for the FM and CDMA AGC input stages. This pin may
be connected in parallel with pins 1 and 2. It should be bypassed by a
10nF capacitor. The trace length between the pin and the bypass
capacitor should be minimized. The ground side of the bypass capaci-
tor should connect immediately to ground plane. The part is designed
to work from a 2.7V to 3.3V supply.
CDMA Balanced Input pin. This pin is internally DC biased and should
be DC blocked if connected to a device with a DC level present. For sin-
gle-ended input operation, one pin is used as an input and the other
CDMA input is AC coupled to ground. The balanced input impedance is
2.4k , while the single-ended input impedance is 1.2k .
Same as pin 4, except complementary input.
Ground connection. Keep traces physically short and connect immedi-
ately to ground plane for best performance.
Same as pin 6.
FM Balanced Input pin. This pin is internally DC biased and should be
DC blocked if connected to a device with DC present. For single-ended
input operation, one pin is used as an input and the other FM input is
AC coupled to ground. The balanced input impedance is 2.4k , while
the single-ended input impedance is 1.2k .
Same as pin 8, except complementary input.
Bandgap Voltage Reference. This voltage, constant over temperature
and supply variation, is used to bias internal circuits. A 10nF external
bypass capacitor is required. The trace length between the pin and the
bypass capacitor should be minimized. The ground side of the bypass
capacitor should connect immediately to ground plane.
AGC decoupling pin. An external bypass capacitor of 10nF capacitor is
required. The trace length between the pin and the bypass capacitor
should be minimized. The ground side of the bypass capacitor should
connect immediately to ground plane.
LO Balanced Input pin. This pin is internally DC biased and should be
DC blocked if connected to a device with DC present. For single-ended
input operation, one pin is used as an input and the other LO input is
AC coupled to ground. The frequency of the signal applied to these
pins is internally divided by a factor of 2, hence the carrier frequency for
the modulator becomes one half of the applied frequency. The single-
ended input impedance is 400
be driven single-ended but balanced provides optimum gain and phase
balance.
Same as pin 12, except complementary input.
(balanced is 800 ). The LO input may
Interface Schematic
CDMA IN+
See pin 4.
See pin 8.
See pin 12.
FM IN+
LO-
BIAS
BIAS
BIAS
400
RF9957
1200
1200
BIAS
BIAS
BIAS
1200
1200
400
CDMA IN-
FM IN-
LO+
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