Datasheet
Table Of Contents
- FEATURES
- APPLICATIONS
- FUNCTIONAL BLOCK DIAGRAM
- GENERAL DESCRIPTION
- PRODUCT HIGHLIGHTS
- SPECIFICATIONS
- ABSOLUTE MAXIMUM RATINGS
- ORDERING GUIDE
- THERMAL CHARACTERISTIC
- PIN CONFIGURATION
- PIN FUNCTION DESCRIPTIONS
- TERMINOLOGY
- Typical Performance Characteristics
- FUNCTIONAL DESCRIPTION
- REFERENCE OPERATION
- REFERENCE CONTROL AMPLIFIER
- PLL CLOCK MULTIPLIER OPERATION
- DAC TIMING WITH PLL ACTIVE
- PLL DISABLED MODE
- INTERLEAVED (2 ) MODE WITH PLL DISABLED
- NONINTERLEAVED MODE WITH PLL DISABLED
- DAC TRANSFER FUNCTION
- ANALOG OUTPUTS
- DIGITAL INPUTS
- INPUT CLOCK AND DATA TIMING RELATIONSHIP
- POWER DISSIPATION
- APPLYING THE AD9753 OUTPUT CONFIGURATIONS
- DIFFERENTIAL COUPLING USING A TRANSFORMER
- DIFFERENTIAL COUPLING USING AN OP AMP
- SINGLE-ENDED UNBUFFERED VOLTAGE OUTPUT
- SINGLE-ENDED BUFFERED VOLTAGE OUTPUT
- POWER AND GROUNDING CONSIDERATIONS, POWER SUPPLY REJECTION
- APPLICATIONS
- EVALUATION BOARD
- OUTLINE DIMENSIONS
- Revision History
REV. B
AD9753
–19–
–30
START 100kHz
–40
–50
–60
–70
–80
–90
–100
–110
–120
–130
12.49MHz/ STOP 125MHz
REF LV1 (dBm)
1RM
–74.34dBm
+9.71442886MHz
–76.86dBm
–80.96dBm
–11.92dBm
1 [T1]
CH PWR
ACP UP
ACP LOW
C11
C0
Cu1
C11
C0
Cu1
MARKER 1 [T1] RBW 5kHz RF ATT 0dB
–74.34dBm VBW 50kHz
9.71442886MHz SWT 12.5 s UNIT dBm
COMMENT A: 25 MSYMBOL, 64 QAM, CARRIER = 25MHz
1
Figure 28. Reconstructed 64-QAM Signal at a 25 MHz IF
A figure of merit for wideband signal synthesis is the ratio of
signal power in the transmitted band to the power in an adja-
cent channel. In Figure 28, the adjacent channel power ratio
(ACPR) at the output of the AD9753 is measured to be 65 dB.
The limitation on making a measurement of this type is often
not the DAC but the noise inherent in creating the digital data
record using computer tools. To find how much this is limiting
the perceived DAC performance, the signal amplitude can be
reduced, as is shown in Figure 29. The noise contributed by the
DAC will remain constant as the signal amplitude is reduced.
When the signal amplitude is reduced to the level where the
noise floor drops below that of the spectrum analyzer, the
ACPR will fall off at the same rate that the signal level is being
reduced. Under the conditions measured in Figure 28, this
point occurs in Figure 29 at –10 dBFS. This shows that the
data record is actually degrading the measured ACPR by up to
10 dB.
A single-channel active mixer such as the Analog Devices AD8343
can then be used for the hop to the transmit frequency. Figure 30
shows an applications circuit using the AD9753 and the AD8343.
The AD8343 is capable of mixing carriers from dc to 2.5 GHz.
Figure 31 shows the result of mixing the signal in Figure 28 up
to a carrier frequency of 800 MHz. ACPR measured at the
output of the AD8343 is shown in Figure 31 to be 59 dB.
AMPLITUDE (dBFS)
80
60
40
0–10–20
ACPR (dB)
70
50
–15 –5
Figure 29. ACPR vs. Amplitude for QAM Carrier
DAC
LATCHES
DAC
INPUT
LATCHES
INPUT
LATCHES
PLL/DIVIDER
CLK+ CLK–
PLLLOCK
DVDD AV DD
I
OUTA
I
OUTB
PORT 1
DATA
INPUT
PORT 2
DATA
INPUT
RSET2
1.9k⍀
FSADJ
0.1F
REFIO ACOM1 ACOM DCOM
AD9753
50⍀
50⍀
0.1F
0.1F
68⍀ 68⍀
INPM
INPP
LOIM
LOIP
OUTP
OUTM
AD8343 ACTIVE MIXER
0.1F
0.1F
LOINPUT
M/A-COM ETC-1-1-13 WIDEBAND BALUN
Figure 30. QAM Transmitter Architecture Using AD9753 and AD8343 Active Mixer