Datasheet

AD6645
Rev. D | Page 11 of 24
FREQUENCY (MHz)
–130
–120
–110
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
AMPLITUDE (dBFS)
2F1 – F2
2F2 + F1
2F1 + F2
F2 – F1
2F2 – F1
F1 + F2
ENCODE = 80MSPS
AIN = 30.5MHz,
31.5MHz (–7dBFS)
NO DITHER
50 10152025303540
02647-022
Figure 16. Two-Tone SFDR @ 30.5 MHz and 31.5 MHz
INPUT POWER LEVEL (F1 = F2 dBFS)
WORST-CASE SPURIOUS (dBFS AND dBc)
0
10
20
30
40
50
60
70
80
90
100
110
dBc
dBFS
SFDR = 90dB
REFERENCE LINE
ENCODE = 80MSPS
F1 = 30.5MHz
F2 = 31.5MHz
–77 –67 –57 –47 –37 –27 –17 –7
02647-023
Figure 17. Two-Tone SFDR @ 30.5 MHz and 31.5 MHz
ENCODE FREQUENCY (MHz)
65
70
80
90
WORST SPUR @ AIN = 2.2MHz
SNR @ AIN = 2.2MHz
75
85
95
100
SNR, WORST-CASE SPURIOUS (dB AND dBc)
15 30 45 60 75 90 105
02647-024
Figure 18. SNR, Worst-Case Spurious vs. Encode @ 2.2 MHz
2F2 – F1
FREQUENCY (MHz)
–130
–120
–110
–100
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
AMPLITUDE (dBFS)
F1 + F2
2F1 – F2
2F2 + F1
2F1 + F2
F2 – F1
ENCODE = 80MSPS
AIN = 55.25MHz,
56.25MHz (–7dBFS)
NO DITHER
50 10152025303540
02647-025
Figure 19. Two-Tone SFDR @ 55.25 MHz and 56.25 MHz
INPUT POWER LEVEL (F1 = F2 dBFS)
WORST-CASE SPURIOUS (dBFS AND dBc)
0
10
20
30
40
50
60
70
80
90
100
110
dBc
dBFS
SFDR = 90dB
REFERENCE LINE
ENCODE = 80MSPS
F1 = 55.25MHz
F2 = 56.25MHz
–77 –67 –57 –47 –37 –27 –17 –7
0
2647-026
Figure 20. Two-Tone SFDR @ 55.25 MHz and 56.25 MHz
ENCODE FREQUENCY (MHz)
65
70
80
90
WORST SPUR @ AIN = 69.1MHz
SNR @ AIN = 69.1MHz
75
85
95
SNR, WORST-CASE SPURIOUS (dB AND dBc)
15 30 45 60 75 90 105
02647-027
Figure 21. SNR, Worst-Case Spurious vs. Encode @ 69.1 MHz