Preliminary
5-32
RF2484
Rev A2 010829
5
Pin
Function
Description
Interface Schematic
1GND
Ground connection. This pin should be connected directly to the
ground plane.
2GND
Same as pin 1.
3GND
Same as pin 1.
4LO
The input of the phase shifting network. This pin has an internal DC
blocking capacitor. This port is voltage-driven so matching at different
frequencies is generally not required.
5GND
Same as pin 1.
6VCC
Power supply. An external capacitor is needed if no other low frequency
bypass capacitor is nearby.
7PD
Power Down control. When this pin is "low," all circuits are shut off. A
"low" is typically 1.2V or less at room temperature.When this pin is
"high" (VCC), all circuits are operating normally. If PD is below VCC, out-
put power and performance will be degraded. Operating in this region
is not recommended, although it might be useful in some applications
where power control is required.
8RF OUT
RF Output. This pin has an internal DC blocking capacitor. At some fre-
quencies, external matching may be needed to optimize output power.
A small amount of DC current may be present at this output. As a
result, if the voltage at this pin is measured using a high impedance
probe, some DC voltage may be observed at this output.
9GND
Same as pin 1.
10
VCC
Same as pin 6.
11
GND
Same as pin 1.
12
GND
Same as pin 1.
13
Q SIG
Baseband input to the Q mixer. This pin is DC coupled. The input drive
level determines output power and linearity performance; for better car-
rier suppression, sideband suppression, and dynamic range, the drive
level should be as high as possible to meet the required linearity perfor-
mance. The recommended DC level for this pin is 4.1V.
For optimum carrier suppression, the DC voltages on I REF, Q REF, I
SIG and Q SIG should be adjusted slightly to compensate for inherent
undesired internal DC offsets; for optimum sideband suppression,
phase and signal amplitude on IREF, Q REF, I SIG and Q SIG should
be adjusted slightly to compensate for inherent undesired internal off-
sets. See RFMD AN0001 for more detail.
14
I SIG
Baseband input to the I mixer. This pin is DC coupled. The input drive
level determines output power and linearity performance; for better car-
rier suppression, sideband suppression, and dynamic range, the drive
level should be as high as possible to meet the required linearity perfor-
mance. The recommended DC level for this pin is 4.1V; see pin 13 for
more information.
15
I REF
Reference voltage for the I mixer. This voltage should be the same as
the DC voltage supplied to the I SIG pin. A voltage of 4.1V is recom-
mended; see pin 13 for more information.
The SIG and REF inputs are inputs of a differential amplifier. Therefore
the REF and SIG inputs are interchangeable. If swapping the I SIG and
I REF pins, the Q SIG and Q REF also need to be swapped to maintain
the correct phase. It is also possible to drive the SIG and REF inputs in
a differential mode. This will increase the gain.
LO
200
Ω
PD
V
CC
RF OUT
100
Ω
1p
V
CC
100
Ω
1p
V
CC
100
Ω
1p
V
CC
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