AD7866 Analog Devices, AD7866 Datasheet - Page 13

• Manufacturer Part Number: AD7866
• Description: Dual 1MSPS, 12-Bit, 2-Channel SAR ADC with Serial Interface
• Manufacturer: Analog Devices

Specifications of AD7866

• Resolution (bits): 12bit
• # Chan: 4
• Sample Rate: 1MSPS
• Interface: Ser,SPI
• Analog Input Type: SE-Uni
• Ain Range: Uni (Vref),Uni (Vref) x 2,Uni 2.5V,Uni 5.0V
• Adc Architecture: SAR
• Pkg Type: SOP

REV. A
Figure 10. Straight Binary Transfer
Characteristic with 0 V to V
111...111
111...110
111...000
011...111
000...010
000...001
000...000
Figure 7. Selecting V
Figure 8. Selecting 0 V to 2
0V
RANGE
RANGE
D
D
D
D
SCLK
SCLK
OUT
OUT
OUT
OUT
1LSB
CS
CS
0V
A
B
A
B
V
ANALOG INPUT
REF
1LSB = V
Figure 9. Handling Bipolar Signals with the AD7866
R1 = R2 = R3 = R4
A
A
Input Range
V
REF
V
REF
1
1
REF
/2 ± V
– 1LSB
/4096
R3
R2
REF
R4
100nF
B
B
R1
/2 Input Range with Twos Complement Output Coding
V
8
8
REF
Input Range with Straight Binary Output Coding
470nF
V
REF
470nF
–13–
16
16
D
D
V
V
–V
+V
CAP
CAP
REF
IN
V
REF SELECT
REF
REF
AD7866
REF
B
A
V
0V TO 2
INPUT RANGE
INPUT RANGE
REF
Figure 11. Twos Complement Transfer
Characteristic with V
(= 0V)
V
(= 2
/2
DRIVE
D
OUT
V
REF
V
V
REF
REF
COMPLEMENT
/2
011...111
011...110
000...001
000...000
111...111
100...010
100...001
100...000
)
TWOS
1
1
TWOS COMPLEMENT
–V
STRAIGHT BINARY
REF
011
000
100
+ 1LSB
1LSB = 2
111
000
000
V
REF
REF
DSP/ P
ANALOG INPUT
V
V
DD
DD
– 1LSB
± V
V
16
16
REF
REF
/4096
+V
REF
Input Range
– 1LSB
AD7866