1
dc2391af
DEMO MANUAL DC2391A
DESCRIPTION
LTC5589
700MHz to 6000MHz LOW
POWER I/Q MODULATOR
Demonstration circuit 2391A is optimized for evaluation
of the
LTC
®
5589
low power I/Q modulator up to 4.5GHz.
For frequencies above 4.5GHz, LO matching circuit on
the DC2391A demo board can be easily modified for
improved image rejection performance. Refer to data
sheet for additional information. The four balanced I- and
Q-baseband input ports can be either AC-coupled with
internal bias supplied, or DC-coupled from a source with
a common-mode voltage level of about +1.4V. The SPI
interface is used to set internal registers which control
the gain, optimum center frequency, I-offset, Q-offset and
sideband suppression. In addition to the digital gain control
with 1dB steps, there is an analog gain control, V
CTRL
. An
on-chip thermometer can be used to compensate for the
gain vs temperature variations using a digital gain control
change. The update can either be automatically triggered,
or entirely switched off.
L
, LT, LTC, LTM, Linear Technology , the Linear logo and Linduino are registered trademarks
and QuikEval is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2391A
Figure 1: Test Setup for RF Performance Measurements
TEST SETUP
SPECTRUM
ANALYZER
OR VSA
IQ BASEBAND
GENERATOR
LO SIGNAL
GENERATOR
DVM
+
–
POWER SUPPLY
+3.3V
IQ INPUTS
LTC5589
ON
DC2391A
RF
LO
GND SPI
EN
+3.3V
2560MHz, 0dBm NOM.
+
–
Linduino
®
ONE
DC2026C
USB SERIAL
CONTROLLER
USB
SPI
PC
USB
RIBBON CABLE
DC2391A F01
ABSOLUTE MAX INPUT RATINGS
Supply Voltage: .....................................................+3.8V
Common Mode Level of
BBPI, BBMI, BBPQ, and BBMQ: ........................... +2V
LOL, LOC DC Voltage: .........................................±50mV
LOL, LOC Input Power: .....................................+20dBm
TEMP, SDO Current Sink .......................................10mA
Voltage on Any Pin Not
to Exceed ..................................–0.3V to (V
CC
+0.3V)
T
JMAX
....................................................................150°C
Operating Temperature Range .............. –40°C to 105°C
Storage Temperature Range ................. –65°C to 150°C
CAUTION
: This part is sensitive to electrostatic discharge
(ESD). Observe proper ESD precautions when handling
the LTC5589.
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