Datasheet

AD7685
Rev. C | Page 10 of 28
TYPICAL PERFORMANCE CHARACTERISTICS
02968-047
CODE
655360 16384 32768 49152
INL (LSB)
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
POSITIVE INL = +0.33LSB
NEGATIVE INL = –0.50LSB
Figure 7. Integral Nonlinearity vs. Code
02968-006
CODE IN HEX
80EA 80EB 80EC 80ED80E5 80E6 80E7 80E8 80E9
COUNTS
250000
200000
150000
100000
50000
0
0012 00
204292
27755
29041
20
VDD = REF = 5V
Figure 8. Histogram of a DC Input at the Code Center
02968-007
FREQUENCY (kHz)
1200 20406080100
AMPLITUDE (dB OF FULL SCALE)
0
–20
–40
–60
–80
–100
–120
–160
–140
–180
8192 POINT FFT
VDD = REF = 5V
f
S
= 250kSPS
f
IN
= 20.45kHz
SNR = 93.3dB
THD = –111.6dB
SFDR = –113.7dB
SECOND HARMONIC = –113.7dB
THIRD HARMONIC = –117.6dB
Figure 9. FFT Plot
02968-008
CODE
655360 16384 32768 49152
DNL (LSB)
2.0
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
POSITIVE DNL = +0.21LSB
NEGATIVE DNL = –0.30LSB
Figure 10. Differential Nonlinearity vs. Code
02968-009
CODE IN HEX
8058804E 804F 8050 8051 8052 8053 8054 8055 8056 8057
COUNTS
140000
120000
100000
80000
60000
40000
20000
0
02 213
6956
179 0 0
60966
125055
8667
59082
VDD = REF = 2.5V
Figure 11. Histogram of a DC Input at the Code Center
02968-010
FREQUENCY (kHz)
1200 20406080100
AMPLITUDE (dB OF FULL SCALE)
0
–20
–40
–60
–80
–100
–120
–140
–160
–180
16384 POINT FFT
VDD = REF = 2.5V
f
S
= 250kSPS
f
IN
= 20.45kHz
SNR = 88.8dB
THD = –103.5dB
SFDR = –104.5dB
SECOND HARMONIC = –112.4dB
THIRD HARMONIC = –105.4dB
Figure 12. FFT Plot