RF2480
Pin
1
Function
I REF
Description
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 3.0V is recom-
mended. 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 balanced mode. This will increase the gain.
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.
Reference voltage for the Q mixer. This voltage should be the same as
the DC voltage supplied to the Q SIG pin. A voltage of 3.0V is recom-
mended. See pin 1 for more details.
Interface Schematic
I SIG
100
Ω
I REF
100
Ω
425
Ω
425
Ω
2
Q REF
Q SIG
100
Ω
Q REF
100
Ω
5
MODULATORS AND
UPCONVERTERS
425
Ω
425
Ω
3
4
5
6
7
8
GND2
GND2
GND2
LO
VCC1
PD
Ground connection of the LO phase shift network. This pin should be
connected directly to the ground plane.
Same as pin 3.
Same as pin 3.
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 not required.
Power supply for all circuits except the RF output stage. An external
capacitor is needed if no other low frequency bypass capacitor is
nearby.
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" (V
CC
), all circuits are operating normally. If PD is below V
CC
, 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.
RF Output. This pin has an internal DC blocking capacitor. At some fre-
quencies, external matching may be needed to optimize output power.
LO
V
CC
200
Ω
PD
9
RF OUT
RF OUT
10
11
12
13
14
GND3
VCC2
GND1
GND1
GND1
Ground connection for the RF output stage. This pin should be con-
nected directly to the ground plane.
Power supply for the RF output amplifier. An external capacitor is
needed if no other low frequency bypass capacitor is near by.
Ground connection for the LO and baseband amplifiers, and for the
mixers. This pin should be connected directly to the ground plane.
Same as pin 12.
Same as pin 12.
5-32
Rev A3 011019
RFMD [ RF MICRO DEVICES ]
