Datasheet

AD7946
Rev. A | Page 8 of 24
TYPICAL PERFORMANCE CHARACTERISTICS
CODE
INL (LSB)
04656-006
1.0
0.8
0.6
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
0 4096 8192 12288 16384
POSITIVE INL = +0.17LSB
NEGATIVE INL = –0.26LSB
Figure 6. Integral Nonlinearity vs. Code
04656-046
0
50000
100000
150000
200000
250000
300000
2009 200A 200B 200C 200D 200E 200F
CODE IN HEX
COUNTS
000 0
261120
00
VDD = REF = 5V
Figure 7. Histogram of a DC Input at the Code Center
FREQUENCY (kHz)
AMPLITUDE (dB of Full Scale)
04656-008
0
–20
–40
–60
–80
–100
–120
–140
–160
–180
0 20 40 60 80 100 120 140 160 180 200 220 240
8192 POINT FFT
VDD = REF = 5V
f
S
= 500kSPS
f
IN
= 20.14kHz
SNR = 85.3dB
THD = –105.2dB
SECOND HARMONIC = –106dB
THIRD HARMONIC = –110dB
Figure 8. FFT Plot
CODE
DNL (LSB)
04656-009
POSITIVE DNL = +0.20LSB
NEGATIVE DNL = –0.13LSB
1.0
0.8
0.6
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
0 4096 8192 12288 16384
Figure 9. Differential Nonlinearity vs. Code
04656-047
0
25000
50000
75000
100000
125000
150000
2059 205A 205B 205C 205D 205E
CODE IN HEX
COUNTS
0
0
131592
129528
00
VDD = REF = 5V
Figure 10. Histogram of a DC Input at the Code Transition
INPUT LEVEL (dB)
SNR REFERENCE TO FULL SCALE (dB)
04656-011
80
82
84
86
88
90
–10–8–6–4–2
Figure 11. SNR vs. Input Level