AD7720 Analog Devices, AD7720 Datasheet - Page 8

• Manufacturer Part Number: AD7720
• Description: CMOS Sigma-Delta Modulator with 90 dB Dynamic Range
• Manufacturer: Analog Devices

Specifications of AD7720

• Resolution (bits): 16bit
• # Chan: 1
• Sample Rate: 25MSPS
• Interface: Ser
• Analog Input Type: Diff-Bip,Diff-Uni
• Ain Range: (Vref) p-p,2.5V p-p,Uni (Vref),Uni 2.5V
• Adc Architecture: Sigma-Delta Modulator
• Pkg Type: SOP

AD7720–Typical Characteristics
(AVDD = DVDD = 5.0 V, T
noted)
Figure 8. SNR, THD, and SFDR vs.
Input Frequency
Figure 11. THD vs. Temperature
Figure 5. S/(N+D) and SFDR vs.
Analog Input Level
–100
–105
–110
–115
–100
–102
–104
–106
–108
–110
–112
–114
–116
110
100
–85
–90
–95
–94
–96
–98
90
80
70
60
50
–50
–40
0
SFDR
THD
SNR
–25
20
–30
INPUT FREQUENCY – kHz
TEMPERATURE – C
INPUT LEVEL – dB
SFDR
0
V
V
IN
CM
40
(+) = V
= 2.5V
–20
25
A
THD
= +25 C; CLKIN = 12.5 MHz, AIN = 20 kHz, Bipolar Mode; V
IN
60
(–) = 1.25Vpk–pk
S/ (N+D)
50
–10
80
75
3RD
2ND
4TH
100
100
0
Figure 6. S/(N+D) vs. Output Sample
Rate
Figure 9. S/(N+D) vs. Output Sample
Rate
Figure 12. Histogram of Output Codes
with DC Input
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
84
85
86
87
88
89
90
91
92
84
85
86
87
88
89
90
91
92
0
n–3
0
0
AIN = 1/5
AIN = 1/5
V
V
n–2
50
IN
CM
50
OUTPUT DATA RATE – kSPS
OUTPUT DATA RATE – kSPS
(+) = V
= 2.5V
100
100
n–1
·
·
IN
BW
–8–
BW
(–) = 1.25Vpk–pk
CODES
150
150
n
V
CLKIN = 12.5MHz
8k SAMPLES
IN
200
200
(+) = V
n+1
IN
n+2
250
250
(–)
IN
(+) = 0 V to 2.5 V, V
300
300
n+3
Figure 7. SNR, THD, and SFDR vs.
Input Frequency
Figure 10. SNR vs. Temperature
Figure 13. Differential Nonlinearity
–100
–105
–110
–115
–0.2
–0.4
–0.6
–0.8
–1.0
92.0
91.5
91.0
90.5
90.0
89.5
89.0
88.5
88.0
–85
–90
–95
1.0
0.8
0.6
0.4
0.2
0
–50
0
IN
0
(–) = 1.25 V unless otherwise
20
INPUT FREQUENCY – kHz
20000
SNR
TEMPERATURE – C
0
40
CODE
THD
40000
60
SFDR
50
80
REV. 0
65535
100
100