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dc2091afa

DEMO MANUAL DC2091A

notes on test equipMent anD setup

• Use high performance signal generators with fully

configurable differential I and Q outputs, such as the

Rohde & Schwarz SMJ100A vector signal generator or

equivalent.

• Use narrow resolution bandwidth (RBW) and engage

video averaging on the spectrum analyzer to lower the

displayedaveragenoiselevel(DANL)inordertoimprove

sensitivity and to increase dynamic range. The trade-off

is increased sweep time.

• Spectrum analyzers can produce significant internal dis-

tortionproductsiftheyareoverdriven.Generally,spectrum

analyzers are designed to operate at their best with about

–30dBm to –40dBm at their input filter or preselector.

Sufficient spectrum analyzer input attenuation should be

used to avoid saturating the instrument, but too much

attenuation reduces sensitivity and dynamic range.

• Before taking measurements, the system performance

should be evaluated to ensure that:

1) clean input signals can be produced

2) the spectrum analyzer’s internal distortion is mini-

mized

3) the spectrum analyzer has enough dynamic range

and sensitivity

4) the system is accurately calibrated for power and

frequency.

• Digital modulation often requires DC coupling and flat

frequency response. For best EVM performance with

complex modulation, the RC networks at the baseband

I/Q inputs are not required.

quick start proceDure

1. Remove the demonstration circuit from its protective

packaging in an ESD-safe working area.

2. Turn off the DC power supply as well as the baseband

and LO signal sources’ outputs.

3. Connect all test equipment as show in Figure 1.

4. Make sure jumper JP1 is installed and the jumper JP2

is installed at the 1-2 position.

5. Slowly increase the supply voltage to 3.3V. Do not

exceed 3.8V.

6. Turn on the baseband signal source. Set the baseband

common mode bias to 1.4V.

7. Verify the total VCC supply current is approximately

28mA. The demonstration circuit is now turned on

and is ready for measurements.

8. Turn on the output of the LO source and apply a

492.8MHz, 0dBm CW Signal.

9. Set the baseband signal source to provide a 100kHz,

200mVP-P(DIFF) baseband input signal. The I and Q

channels should be 90° shifted and set for lower

sideband selection.

10. Measure the modulator’s RF output on the Spectrum

Analyzer at 492.7MHz.

absolute MaxiMuM input ratings

Supply Voltage.........................................................3.8V

Common Mode Level of BBPI, BBMI,

and BBPQ, BBMQ ...................................................2V

LOL, LOC DC Voltage ............................................. ±0.1V

LOL, LOC Input Power .........................................20dBm

Voltage on Any Pin...........................–0.3V to VCC + 0.3V

TJMAX.................................................................... 150°C

Case Operating Temperature Range....... –40°C to 105°C

Storage Temperature Range .................. –65°C to 150°C

CAUTION: ThIS PART IS SeNSITIve TO eleCTRO-

STATIC DISChARge (eSD). ObSeRve PROPeR eSD

PReCAUTIONS wheN hANDlINg The lTC5599.