Datasheet

AD7980 Data Sheet
Rev. C | Page 10 of 28
180k
0
800C 800D 800E 800F80098008 800B800A8003 80058004 80078006
2 0 0 0
33829
0
27
0
1201
06392-042
CODE IN HEX
COUNTS
140k
160k
100k
120k
60k
20k
80k
40k
38751
168591
52710
Figure 12. Histogram of a DC Input at the Code Center, REF = 5 V
70k
0
7FFF 8008
80018000 8003
8002 80058004 8007
8006
0
0
150
2
59691
5428
59404
3
93
06392-043
CODE IN HEX
COUNTS
60k
50k
30k
10k
40k
20k
6295
Figure 13. Histogram of a DC Input at the Code Transition, REF = 5 V
100
80
85
90
95
2.25 5.25
06392-044
REFERENCE VOLTAGE (V)
SNR, SINAD (dB)
16
12
13
14
15
ENOB (BITS)
2.75 3.25 3.75 4.25 4.75
SNR
SINAD
ENOB
Figure 14. SNR, SINAD, and ENOB vs. Reference Voltage
60k
0
7F
F
A 80067FFC
7FFB 7FFE
7FFF
7FFD 8001
8000
8003 8004 80058002
0
0
0
0
539
16
14
502
06392-059
CODE IN HEX
COUNTS
50k
30k
10k
40k
20k
32417
52212
31340
7225
6807
Figure 15. Histogram of a DC Input at the Code Center, REF = 2.5 V
95
85
87
89
92
91
93
94
86
88
90
–10 0
06392-046
INPUT LEVEL (dB OF FULL SCALE)
SNR (dB)
–9 –8 –7 –6 –5
–4 –3 –2
–1
Figure 16. SNR vs. Input Level
–95
–125
–110
–115
–105
–100
–120
115
85
100
95
105
110
90
2.25 5.25
06392-047
REFERENCE VOLTAGE (V)
THD (dB)
SFDR (dB)
2.75 3.25 3.75
4.25 4.75
THD
SFDR
Figure 17. THD, SFDR vs. Reference Voltage