RF9958 Datasheet, PDF (5/12 Pages) RF Micro Devices – CDMA/FM TRANSMIT MODULATOR, IF AGC, AND UPCONVERTER

RF9958
Pin Function Description
Interface Schematic
10
BG OUT ^{Bandgap voltage reference. This voltage, constant over temperature}
and supply variation, is used to bias internal circuits. A 1nF external
bypass capacitor is required.
11
VCC3
Supply voltage for the AGC and the Bandgap circuitry. A 1nF external
bypass capacitor is required and an additional 0.1µF will be required if
no other low frequency 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.
12
GND1
Same as pin 6.
13
PD1
Power down control for overall circuit. When logic “high” (≥V_CC-0.7V),
all circuits are operating; when logic “low” (≤0.5V), all circuits are
turned off. The input impedance of this pin is >10kΩ. A DC voltage less
10 kΩ
PD1
than or equal to the maximum allowable Vcc may be applied to this pin
when no voltage is applied to the Vcc pins.
14
VCC4
Supply for the mixer stage only. The supply for the mixer is separated to
5
maximize IF to RF isolations and reduce the carrier leakage. A 100pF
external bypass capacitor is required and an additional 0.1µF will be
required if no other low frequency bypass capacitors are nearby. The
trace length between the pin and the bypass capacitors should be min-
imized. The ground side of the bypass capacitors should connect
immediately to ground plane.
15
PD2
Power down control for mixer only. When connected to pin 10 (BG
OUT) the mixer circuits are operating; when connected to ground
(≤0.5V), the mixer is turned off but all other circuits are operating. A DC
voltage less than or equal to the maximum allowable Vcc may be
PD2
1 kΩ
applied to this pin when no voltage is applied to the Vcc pins.
450 Ω
16
GND2
Ground connection for the mixer stage. Keep traces physically short
and connect immediately to ground plane for best performance.
17
RF OUT ^{RF output pin. An external shunt inductor to V}CC ^{plus a series blocking/}
V_CC4
matching capacitor are required for 50Ω output.
300 Ω
RF OUT
18
DEC
Current Mirror decoupling pin. A 1000pF external capacitor is required
to bypass this pin. The ground side of the bypass capacitors should
connect immediately to ground plane.
19
LO2+
One half of the balanced mixer LO2 input. In single-ended applications,
BIAS
the other half of the input, LO2- is AC grounded. This is a 50Ω imped-
ance port. This pin is NOT internally DC blocked. An external blocking
capacitor (100pF recommended) must be provided if the pin is con-
40 Ω
nected to a device with DC present.
LO2+
BIAS
40 Ω
LO2-
20
LO2-
21
MIX IN-
Rev B11 010720
One half of the balance mixer LO2 input. In single ended applications,
this pin is AC grounded with a 100pF capacitor.
One half of the 200Ω balanced impedance input to the mixer stage.
This pin is NOT internally DC blocked. An external blocking capacitor
(2200pF recommended) must be provided if the pin is connected to a
device with DC present. If no IF filter is needed this pin may be con-
nected to MOD OUT+ through a DC blocking capacitor. An appropriate
matching network may be needed if an IF filter is used.
See pin 19.
BIAS
100 Ω
MIX IN-
BIAS
100 Ω
MIX IN+
5-97