Linear Technology DC426B Quick Start Quide page 3

LT5511 Upconverting Mixer Two-Tone Measurements for 1900MHz Band.
1. Connect all test equipment as shown in Figure 3.
Note: 1). A high quality combiner that provides 50-ohm termination on all ports and has
good port-to-port isolation should be used.
2). The two 3dB attenuators on the inputs of the combiner are used to further improve
source isolation.
2. Set the Power Supply output voltage to 5V, and set the current limit to 100mA.
3. Set the dipswitch SW1 (Enable) to 1. Mixer is in ENABLE mode.
4. Set the Signal Generator #1 to provide a 1950MHz, -10dBm, CW signal to the demo board
LOin port.
5. Set the Signal Generator #2 and #3 to provide two -5dBm CW signals to the demo board IFin
port—one at 50MHz, and the other at 51MHz.
6. Set the Spectrum Analyzer's center frequency to 1899.5MHz. Perform input 3
distortion measurement. (IIP3 = P1 + (P1 – P3) / 2 – Gc, where P1 is the lowest power level
of the two desired output tones at either 1899MHz or 1900MHz, P3 is the largest 3
product at either 1898MHz or 1901MHz, and Gc is conversion gain. P1 and P3 are in units
of dBm, and Gc is in dB.)
SIGNAL
GENERATOR 1
SIGNAL
GENERATOR 2
Figure 3. Test Set-Up for Mixer Two-Tone Measurements
∑
3dB PAD 3dB PAD
rd
order
rd
order
SPECTRUM
ANALYZER
POWER SUPPLY
SIGNAL
GENERATOR 3
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