Datasheet
AD9224
–20–
REV. A
The distortion and noise performance of an ADC at the given
IF frequency is of particular concern when evaluating an ADC
for a narrowband IF sampling application. Both single tone and
dual tone SFDR vs. amplitude are very useful in assessing an
ADC’s dynamic and static nonlinearities. SNR vs. amplitude
performance at the given IF is useful in assessing the ADC’s
noise performance and noise contribution due to aperture jitter.
In any application, one is advised to test several units of the
same device under the same conditions to evaluate the given
applications sensitivity to that particular device.
Figures 36–39 combine the dual tone SFDR as well as single
tone SFDR and SNR performances at IF frequencies of 35 MHz,
45 MHz, 71 MHz, and 85 MHz. Note, the SFDR vs. amplitude
data is referenced to dBFS while the single tone SNR data is
referenced to dBc. The performance characteristics in these
figures are representative of the AD9224 without any preceding
gain stage. The AD9224 was operated in the differential mode
(via transformer) with a 2 V span and a sample rate between
28 MSPS and 36 MSPS. The analog supply (AVDD) and the
digital supply (DRVDD) were set to +5 V and +3.3 V respectively.
A
IN
– dBFS
100
0
–0.5 –30–5
SNR/SFDR – dBc/dBFS
–10
–15
–20 –25
90
60
30
20
10
80
70
50
40
SFDR-SINGLE
TONE (dBFS)
SFDR-DUAL
TONE (dBFS)
SNR-SINGLE
TONE (dBc)
Figure 36. IF Undersampling at 35 MHz (F
1
= 34.64 MHz,
F
2
= 35.43 MHz, f
CLOCK
= 28 MSPS)
A
IN
– dBFS
100
0
–0.5 –30–5
SNR/SFDR – dBc/dBFS
–10
–15
–20 –25
90
60
30
20
10
80
70
50
40
SFDR-SINGLE
TONE (dBFS)
SFDR-DUAL
TONE (dBFS)
SNR-SINGLE
TONE (dBc)
Figure 37. IF Undersampling at 45 MHz (F
1
= 44.53 MHz,
F
2
= 45.55 MHz, f
CLOCK
= 36 MSPS)
A
IN
– dBFS
100
0
–0.5 –30–5
SNR/SFDR – dBc/dBFS
–10 –15 –20 –25
90
60
30
20
10
80
70
50
40
SFDR-SINGLE
TONE (dBFS)
SFDR-DUAL
TONE (dBFS)
SNR-SINGLE
TONE (dBc)
Figure 38. IF Undersampling at 70 MHz (F
1
= 70.46 MHz,
F
2
= 71.36 MHz, f
CLOCK
= 31.5 MSPS)
A
IN
– dBFS
100
0
–0.5 30–5
SNR/SFDR – dBc/dBFS
–10 –15 –20 –25
90
60
30
20
10
80
70
50
40
SFDR-SINGLE
TONE (dBFS)
SFDR-DUAL
TONE (dBFS)
SNR-SINGLE
TONE (dBc)
Figure 39. IF Undersampling at 85 MHz (F
1
= 84.46 MHz,
F
2
= 85.36 MHz, f
CLOCK
= 31 MSPS)