Datasheet

AD6644
Rev. D | Page 10 of 24
ANALOG FREQUENCY (MHz)
HARMONICS (dBc)
95
75
60
55
85
65
80
100
70
90
WORST OTHER SPUR
HARMONICS (SECOND, THIRD)
0 102030405060708090100
ENCODE = 65MSPS
AIN = –1dBFS
00971-010
Figure 10. Harmonics vs. Analog Frequency (IF)
ANALOG INPUT POWER LEVEL (dBFS)
WORST-CASE SPURIOUS (dBFS and dBc)
100
50
10
0
90
40
70
120
20
30
60
80
110
dBc
dBFS
ENCODE = 65MSPS
AIN = 15.5MHz
SFDR = 90dB
REFERENCE LINE
–80 –70 –60 –50 –40 –30 –20 –10 0
00971-011
Figure 11. Single-Tone SFDR
FREQUENCY (MHz)
0
–120
–130
–110
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
(dBFS)
0 5 10 15 20 25 30
ENCODE = 65MSPS
AIN = 19MHz,
19.5MHz @ –7dBFS
NO DITHER
00971-012
Figure 12. Two Tones at 19 MHz and 19.5 MHz
FREQUENCY (MHz)
0
–120
–130
–110
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
(dBFS)
0 5 10 15 20 25 30
ENCODE = 65MSPS
AIN = 15MHz,
15.5MHz @ –7dBFS
NO DITHER
00971-013
Figure 13. Two Tones at 15 MHz and 15.5 MHz
WORST-CASE SPURIOUS (dBFS and dBc)
100
50
10
0
90
40
70
20
30
60
80
110
dBFS
dBc
ENCODE = 65MSPS
F1 = 15MHz
F2 = 15.5MHz
SFDR = 90dB
REFERENCE LINE
INPUT POWER LEVEL [(F1 = F2) dBFS]
–77 –67 –57 –47 –37 –27 –17 –7
00971-014
Figure 14. Two-Tone SFDR
ENCODE FREQUENCY (MHz)
SNR, WORST SPURIOUS (dB and dBc)
65
60
95
75
85
70
80
90
100
WORST SPUR
SNR
AIN = 2.2MHz @ –1dBFS
0 102030405060708090
00971-015
Figure 15. SNR, Worst Spurious vs. Encode