Datasheet

AD7707
Rev. B | Page 12 of 52
TYPICAL PERFORMANCE CHARACTERISTICS
CODE
32,764
OCCURRENCE
400
0
32,765 32,766 32,767 32,768 32,769 32,770
300
200
100
08691-007
READING NUMBER
32,763
0100
CODE READ
32,764
32,765
32,766
32,767
32,768
32,769
32,770
32,771
200 300 400 500 600 700 800 900 1000
V
DD
= 5V
V
REF
= 2.5V
GAIN = 128
50Hz UPDATE RATE
T
A
= 25°C
RMS NOISE = 600nV
08691-004
Figure 4. Typical Noise Plot at Gain = 128 with 50 Hz Update Rate for Low
Level Input Channel
Figure 7. Histogram of Data in Figure 4
READING NUMBER
0
CODE
32,769
32,768
32,767
32,766
10Hz UPDATE RATE, UNBUFFERED MODE
GAIN = 2 (±10V INPUT RANGE)
BIPOLAR MODE
ANALOG INPUT SET ON CODE TRANSITION
200 400 600 800 1000
08691-005
CODE
OCCURRENCE
0
800
700
600
500
400
300
200
100
08691-008
10Hz UPDATE RATE
UNBUFFERED MODE
BIPOLAR MODE
GAIN = 2
(±10V INPUT RANGE)
1
32,767
2
32,768
Figure 8. Histogram of Data in Figure 5
Figure 5. Typical Noise Plot for AIN3, High Level Input Channel
AIN3 (V)
–10
RMS NOISE (µV)
7
8
9
10
–6 –2 2 6 10
BUFFERED MODE
UNBUFFERED MODE
6
5
4
3
2
1
0
08691-006
HIGH LEVEL INPUT CHANNEL
±10V INPUT RANGE
10Hz UPDATE RATE
AV
DD
= DV
DD
= 5V
REF IN(+) = 2.5V
REF IN(–) = AGND
T
A
= 25°C
INPUT VOLTAGE (mV)
–20
RMS NOISE (µV)
0
0.2
0.4
0.6
02510101–51–
BUFFERED MODE
UNBUFFERED MODE
–5 0 5
0.5
0.3
0.1
08691-009
LOW LEVEL INPUT CHANNEL
GAIN = 128
10Hz UPDATE RATE
AV
DD
= DV
DD
= 5V
REF IN(+) = 2.5V
REF IN(–) = AGND
T
A
= +25°C
Figure 6. Typical RMS Noise vs. Analog Input Voltage for High Level Input
Channel, AIN3
Figure 9. Typical RMS Noise vs. Analog Input Voltage for Low Level Input
Channels, AIN1 and AIN2