AD7705/AD7706
TYPICAL PERFORMANCE CHARACTERISTICS
32771
400
300
200
V
V
= 5V
T = 25°C
DD
A
= 2.5V
RMS NOISE = 600nV
REF
32770
32769
GAIN = +128
50Hz UPDATE RATE
32768
32767
32766
32765
32764
32763
100
0
0
100 200 300 400 500 600 700 800 900 1000
READING NUMBER
32764
32765
32766
32767
CODE
32768 32769
32770
Figure 5. Noise @ Gain = +128 With 50 Hz Update Rate
Figure 8. Histogram of Data in Figure 5
1.2
1.0
0.8
0.6
0.4
1.2
1.0
0.8
0.6
0.4
V
T
= 3V
V
= 5V
= +25°C
DD
= 25°C
DD
T
A
A
BUFFERED MODE, GAIN = +128
BUFFERED MODE, GAIN = +128
BUFFERED MODE, GAIN = +1
BUFFERED MODE, GAIN = +1
UNBUFFERED MODE, GAIN = +128
UNBUFFERED MODE, GAIN = +128
UNBUFFERED MODE, GAIN = +1
0.2
0
0.2
0
UNBUFFERED MODE, GAIN = +1
0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6
FREQUENCY (MHz)
0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6
FREQUENCY (MHz)
Figure 6. IDD vs. MCLK IN Frequency @ 3 V
Figure 9. IDD vs. MCLK IN Frequency @ 5 V
1.0
1.2
BUFFERED MODE
= 5MHz,
CLKDIV = 1
BUFFERED MODE
= 5MHz,
CLKDIV = 1
f
f
CLK
CLK
0.9
0.8
1.0
0.8
0.6
0.4
BUFFERED MODE
= 2.4576MHz, CLKDIV = 0
BUFFERED MODE
= 2.4576MHz, CLKDIV = 0
UNBUFFERED MODE
UNBUFFERED MODE
f
f
CLK
CLK
f
= 1MHz,
f
= 1MHz,
CLK
CLKDIV = 0
CLK
CLKDIV = 0
0.7
0.6
0.5
UNBUFFERED MODE
= 5MHz, CLKDIV = 1
UNBUFFERED MODE
= 5MHz, CLKDIV = 1
f
CLK
f
CLK
0.4
0.3
0.2
UNBUFFERED MODE
UNBUFFERED MODE
= 2.84MHz, CLKDIV = 0
f
= 2.4576MHz, CLKDIV = 0
CLK
f
CLK
V
= 3V
V
= 5V
DD
DD
0.2
0
BUFFERED MODE
EXTERNAL MCLK
CLKDIS = 1
EXTERNAL MCLK
CLKDIS = 1
BUFFERED MODE
= 1MHz, CLKDIV = 0
f
= 1MHz, CLKDIV = 0
f
CLK
0.1
0
CLK
T
= 25°C
T
= 25°C
A
A
1
2
4
8
16
32
64
128
1
2
4
8
16
32
64
128
GAIN
GAIN
Figure 10. IDD vs. Gain and Clock Frequency @ 5 V
Figure 7. IDD vs. Gain and Clock Frequency @ 3 V
Rev. C | Page 14 of 44