Linear Technology LTC5599 Demo Manual

Description

Demonstration circuit 2091A is optimized for evaluation
of the LTC 5599 low power direct quadrature modulator.
®
The balanced I and Q baseband input ports can be either
AC- or DC-coupled to a source with a common mode volt-
age level of about 1.4V. Fixed LC networks on the LO and
RF ports cover a continuous 90MHz to 1300MHz range.
The SPI interface controls the supply current, modulator

MeasureMent setup

BB SIGNAL SOURCE
(V = 1.4V )
CMBB DC
SPECTRUM
ANALYZER
30MHz to 1300MHz Low Power
I +
I –
Q +
Q –
–3dB
Figure 1. Test Setup for RF Performance Measurements
DEMO MANUAL DC2091A
Direct Quadrature Modulator
gain, and allows optimization of the LO carrier feedthrough
and side-band suppression.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2091A
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
QuikEval is a trademark of Linear Technology Corporation. All other trademarks are the property
of their respective owners.
LTC5599
–6dB
LO SIGNAL
SOURCE
– +
DC POWER SUPPLY
(3.3V)
DC2091 F01
dc2091afa
1