Datasheet

AD7291 Data Sheet
Rev. C | Page 8 of 28
TYPICAL PERFORMANCE CHARACTERISTICS
0
–20
–40
–60
–80
–100
–120
0
2k
V
DD
= V
DRIVE
= 3V
f
S
= 22.22ksps
f
SCL
= 400kHz
f
IN
= 10kHz
SNR = 71.209
THD = –81.66
4k
6k 8k 10k
AMPLITUDE (dB)
FREQUENCY (Hz)
08711-009
Figure 4. Typical FFT
1.0
0.8
0.6
0.4
0.2
0
–1.0
–0.8
–0.6
–0.4
–0.2
0 500 1000 1500 2000 2500 3000 3500 4096
INL (LSB)
ADC CODE
08711-010
T
A
= 25°C
V
DRIVE
= 3V
V
REF
= 2.5V
V
DD
= 3V
f
S
= 22.22ksps
f
SCL
= 400kHz
Figure 5. Typical ADC INL
1.0
0.8
0.6
0.4
0.2
0
–1.0
–0.8
–0.6
–0.4
–0.2
0
500 1000 1500 2000 2500 3000 3500
4096
DNL (LSB)
ADC CODE
08711-011
T
A
= 25°C
V
DRIVE
= 3V
V
REF
= 2.5V
V
DD
= 3V
f
S
= 22.22ksps
f
SCL
= 400kHz
Figure 6. Typical ADC DNL
1.0
–1.0
–0.8
–0.6
–0.4
–0.2
0
0.2
0.4
0.6
0.8
0
0.5
1.0
1.5
2.0 2.5 3.0
INL (LSB)
V
REF
(V)
08711-012
IN
L
(POSITIVE)
INL (NEGATIVE)
T
A
= 25°C
V
DRIVE
= 3V
V
DD
= 3V
f
S
= 22.22ksps
f
SCL
= 400kHz
Figure 7. INL vs. External V
REF
1.0
–1.0
–0.8
–0.6
–0.4
–0.2
0
0.2
0.4
0.6
0.8
0 0.5 1.0 1.5 2.0 2.5 3.0
DNL (LSB)
V
REF
(V)
08711-013
DNL (POSITIVE)
DNL (NEGATIVE)
T
A
= 25°C
V
DRIVE
= 3V
V
DD
= 3V
f
S
= 22.22ksps
f
SCL
= 400kHz
Figure 8. DNL vs. External V
REF
11.7
11.6
11.5
11.4
11.3
11.2
0 0.5
1.0 1.5 2.0 2.5
EFFECTIVE NUMBER OF BITS
EXTERNAL REFERENCE (V)
08711-035
Figure 9. Effective Number of Bits vs. V
REF
, f
SCL
= 400 kHz