Datasheet

ADuC814
Rev. A | Page 14 of 72
ADC CODES
LSBs
0
–0.25
–0.20
–0.15
–0.10
–0.50
0
0.05
0.10
0.30
0.25
0.20
0.15
1023511 35833071255920471535 4095
02748-A-014
AV
DD
/DV
DD
= 5V
f
S
= 152kHz
Figure 7. Typical DNL Error, V
DD
= 5 V
ADC CODES
LSBs
0
–0.25
–0.20
–0.15
–0.10
–0.50
0
0.05
0.10
0.30
0.25
0.20
0.15
1023511 35833071255920471535 4095
02748-A-015
AV
DD
/DV
DD
= 3V
f
S
= 152kHz
Figure 8. Typical DNL Error, V
DD
= 3 V
Figure 9 and Figure 10 show the variation in worst-case positive
(WCP) DNL and worst-case negative (WCN) DNL versus
external reference input voltage.
EXTERNAL REFERENCE (V)
–0.6
0.5
WCP–DNL (LSBs)
1.0 2.0 2.5 5.0
–0.4
1.5
–0.2
0
0.2
0.4
0.6
WCN–DNL (LSBs)
–0.4
–0.6
–0.2
0
0.2
0.4
0.6
AV
DD
/DV
DD
= 5V
f
S
= 152kHz
WCP DNL
WCN DNL
02748-A-016
Figure 9. Typical Worst-Case DNL Error vs. V
REF
, V
DD
= 5 V
EXTERNAL REFERENCE (V)
WCP–DNL (LSBs)
0.7
0.5
0.1
–0.5
–0.7
0.3
–0.3
AV
DD
/DV
DD
= 3V
f
S
= 152kHz
0.5 1.0 1.5 2.0 2.5 3.0
WCN–DNL (LSBs)
WCP DNL
WCN DNL
–0.1
0.7
0.5
0.1
–0.5
–0.7
0.3
–0.3
–0.1
02748-A-017
Figure 10. Typical Worst-Case DNL Error vs. V
REF
, V
DD
= 3 V
Figure 11 shows a histogram plot of 10,000 ADC conversion
results on a dc input with V
DD
= 5 V. The plot illustrates an
excellent code distribution pointing to the low noise
performance of the on-chip precision ADC.
CODE
817 818 819 820 821
10000
OCCURRENCE
8000
6000
4000
2000
0
02748-A-018
Figure 11. Code Histogram plot, V
DD
= 5 V
Figure 12 shows a histogram plot of 10,000 ADC conversion
results on a dc input for V
DD
= 3 V. The plot again illustrates a
very tight code distribution of 1 LSB with the majority of codes
appearing in one output bin.
CODE
10000
817 818 819 820 821
OCCURRENCE
8000
6000
4000
2000
0
9000
7000
5000
3000
1000
02748-A-019
Figure 12. Code Histogram Plot, V
DD
= 3 V