Datasheet

50MHz to 500MHz Analog VGA, 1735MHz to 1935MHz
Upconverting Mixer with Image Filtering, Threshold
Alarm Circuit, and Error Amplifier for Level Control
MAX2091
26
Additionally, a lowpass filter can be used between the
VGA output and the mixer input to reduce possible image
noise (RF + LO) at the VGA output from being downcon-
verted to the mixer output. Contact the factory for details.
Alarm Operation
The alarm output (ALM) remains in a logic-high state,
while DET_IN is above 1.35V nominally. ALM_THRES has
135kI input resistance and is set internally to 1.35V (typ),
such that ALM triggers when DET_IN is below 1.35V.
Alternatively, the voltage on ALM_THRES can be exter-
nally driven to allow alternative power-level trip points.
The ALM comparator has a typical hysteresis of 29mV.
Mixer LO Inputs
The mixer is designed to operate with LO+ signal levels
between -10dBm and -4dBm and with LO- grounded. In
cases where V
CC
is applied to the MAX2091 and LO+
is below approximately -15dBm, the mixer’s LO driver
could produce undesired spurious at RF_OUT. In such
a case, applying -10dBm to -4dBm to LO+ returns the
mixer to proper operation. To eliminate the possibility
of spurious at RF_OUT with invalid LO+ signal levels,
power-down mode can be asserted (CTRL1 = CTRL2 =
logic 0) to disable RF_OUT.
Layout Considerations
The pin configuration of the MAX2091 is optimized to
facilitate a very compact physical layout of the device and
its associated discrete components. The exposed pad
Table 2. Typical Application Circuit Component Values
Note: The checkmarks in the Mode of Operation columns indicate that the component is used within each respective application.
*C14 and R11 form an optional lowpass network to filter out potential noise from the external PLVLSET control source.
**R2–R4 form an optional 2.5dB attenuator pad.
COMPONENT
MODE OF OPERATION
VALUE SIZE VENDOR DESCRIPTION
VGA/MIXER
ONLY
CLOSED-ALC
C1, C5, C7
ü ü
1000pF 0402 Murata C0G Dielectric
C2, C3,
C10, C12
ü ü
0.01FF
0402 Murata X7R Dielectric
C4, C11
ü ü
100pF 0402 Murata C0G Dielectric
C8
ü
100nF 0603 Murata X7R Dielectric
C9
ü
820pF 0402 Murata C0G Dielectric
C14* Do Not Install 0402
C15
ü ü
1FF
0603 Murata X7R Dielectric
C16
ü
0.01FF
0402 Murata X7R Dielectric
L1
ü ü
330nH 0603 Coilcraft
Ferrite LS series
5% Tolerance
R1
ü ü
1.78kI
0402 Panasonic 1% Tolerance
R2, R3**
ü ü
7.1I
0402 Panasonic 1% Tolerance
R4**
ü ü
174I
0402 Panasonic 1% Tolerance
R5
ü
150I
0402 Panasonic 1% Tolerance
R7
ü
24kI
0402 Panasonic 5% Tolerance
R11*
ü ü
0I
0402 Panasonic 1% Tolerance
U1
ü ü
—
20-pin TQFN
(5mm x 5mm)
Maxim MAX2091ETP+