Datasheet

AD7747
Rev. 0 | Page 8 of 28
TYPICAL PERFORMANCE CHARACTERISTICS
80
–80
–8 –7 –6 –5 –4 –3 –1–2 8
05469-004
INPUT CAPACITANCE (pF)
INL (ppm)
60
40
20
0
–20
–40
–60
01234567
Figure 4. Capacitance Input Integral Nonlinearity;
V
DD
= 5 V, CAPDAC = 0x3F
2000
–3000
–50 150
05469-005
TEMPERATURE (ºC)
GAIN ERROR (ppm)
1000
0
–1000
–2000
–25 0 25 50 75 100 125
GAIN TC ≈ –28ppm/ºC
Figure 5. Capacitance Input Gain Drift vs. Temperature;
V
DD
= 5 V, CIN(+) to GND = 8 pF
.20
–0.30
–50 150
05469-006
TEMPERATURE (ºC)
OFFSET ERROR (fF)
–25 0 25 50 75 100 125
.15
.10
.050
–0.05
–0.10
–0.15
–0.20
–0.25
Figure 6. Capacitance Input Offset Drift vs. Temperature;
V
DD
= 5 V, CIN(+) Open
10
–50
0 600500
05469-007
CAPACITANCE SHLD TO GND (pF)
CAP ERROR (fF)
0
–20
–10
–30
–40
50 100 150 200 250 300 350 400 450 550
2.7V
3.0V
3.3V
5.0V
Figure 7. Capacitance Input Error vs. Capacitance Between SHLD and GND;
CIN(+) to GND = 8 pF, V
DD
= 2.7 V, 3 V, 3.3 V, and 5 V
10
–50
0 600500
05469-008
CAPACITANCE SHLD TO GND (pF)
CAP ERROR (fF)
0
–20
–10
–30
–40
50 100 150 200 250 300 350 400 450 550
2.7V
3.0V
3.3V
5.0V
Figure 8. Capacitance Input Error vs. Capacitance Between SHLD and GND;
CIN(+) to GND = 25 pF, V
DD
= 2.7 V, 3 V, 3.3 V, and 5 V
10
–50
0 600500
05469-009
CAPACITANCE CIN TO SHLD (pF)
CAP ERROR (fF)
0
–20
–10
–30
–40
50 100 150 200 250 300 350 400 450 550
2.7V
3.0V
3.3V
5.0V
Figure 9. Capacitance Input Error vs. Capacitance Between CIN(+) and SHLD;
CIN(+) to GND = 8 pF, V
DD
= 2.7 V, 3 V, 3.3 V, and 5V