Manual

MAX2683/MAX2684
3.5GHz Downconverter Mixers
with Selectable LO Doubler
______________________________________________________________________________________ 13
(VCO) from the PA, and reducing the demands of
designing a high-frequency VCO. An internal LO band-
pass filter is integrated after the frequency doubler to
help reduce LO harmonic content and spurious mixing.
To enable the LO frequency doubler, drive ENX2 to a
logic-low level and connect the half-frequency external
LO to the LOX2 port. To disable and bypass the LO fre-
quency doubler and LO filter, drive ENX2 to a logic-
high level and connect the full-frequency external LO to
1800 0.254 -98.9 3600 0.271 -164.9
1875 0.262
LOX1
(ENX2 = V
CC
)
LOX2
FREQUENCY
(MHz)
S11 MAG
S11 PHASE
(degrees)
3450 0.306 -167.3
3300 0.338 -167.0
3150 0.358 -165.4
3000 0.362 -163.5
LOX2
(ENX2 = GND)
LOX2
FREQUENCY
(MHz)
S11 MAG
S11 PHASE
(degrees)
1725 0.247 -95.3
1650 0.241 -91.1
1575 0.237 -86.7
1500 0.234 -82.0
-102.3 3750 0.235 -160.6
1950 0.268 -104.9 3900 0.200 -154.8
1500 0.211 -77.9 3000 0.343 -159.1
1575 0.213 -83.7 3150 0.341 -160.0
1650 0.217 -89.3 3300 0.330 -162.3
1725 0.222 -94.5 3450 0.310 -162.0
1800 0.230 -99.3 3600 0.285 -160.2
1875 0.240 -103.6 3750 0.256 -156.4
1950 0.249 -107.1 3900 0.224 -151.1
1500 0.213 -78.0 3000 0.339 -155.2
1575 0.214 -83.7 3150 0.340 -156.0
1650 0.218 -89.3 3300 0.332 -156.0
1725 0.223 -94.5 3450 0.315 -155.3
1800 0.231 -99.3 3600 0.294 -153.3
1875 0.241 -103.7 3750 0.268 -150.0
1950 0.249 -107.2 3900 0.240 -145.5
R
BIAS
= 820Ω
R
BIAS
= 1.2kΩ
R
BIAS
= 2.0kΩ
Table 2. MAX2683 LO Port S-Parameters (V
CC
= +5V, T
A
= +25°C)