AD7922 Analog Devices, AD7922 Datasheet - Page 23

• Manufacturer Part Number: AD7922
• Description: 2-Channel, 2.35 V to 5.25 V, 1 MSPS, 12-Bit A/D Converter
• Manufacturer: Analog Devices

Specifications of AD7922

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

DOUT1
(DIN2)*
DOUT1
(DIN2)*
NOTE
*INFORMATION IN BRACKETS CORRESPONDS TO DATA CLOCKED INTO DIN2 PIN
DOUT
SCLK
DOUT
DOUT
SCLK
SCLK
DIN
CS
DIN
DIN
CS
CS
CONVERSION ON THE
NORMAL MODE
TWO DEVICES
DON'T CARE
DON'T CARE
1
1
SHIFTED INTO THE ADC2
(0, 0, CHN = STY, VALID DATA ADC1)
0, 0, CHN
0, 0, CHN = MOD, VALID DATA ADC1
0, 0, CHN = MOD, VALID DATA ADC2
INTERNAL REGISTER
COMMAND2 WITH CHN
NORMAL CONVERSION
DAISY-CHAIN CYCLE
SHIFTED INTO THE ADC1
≠
MOD, VALID DATA ADC1
DON'T CARE
COMMAND3
INTERNAL REGISTER
10TH–12TH SCLK
10
CHANGE MODE
FALLING EDGE
BETWEEN THE
DON'T CARE
DON'T CARE
CS HIGH
12
≠
STY
14
16
16
EVENTUALLY LOST,
DAISY-CHAIN MODE
THE DATA WILL BE
FROM ONE ADC TO
VALID DATA ADC2
DATA IS SHIFTED
THE NEXT ONE
COMMAND3
Figure 34. Daisy-Chain Diagrams—1
Figure 35. Daisy-Chain Diagrams—II
CH
≠
1
1
STY
DAISY-CHAIN MODE
THE PARTS ENTER
THE PARTS ENTER
Rev. 0 | Page 23 of 32
NORMAL MODE
KEEP THE DEVICES IN
DAISY-CHAIN MODE
DON'T CARE
DON'T CARE
DON'T CARE
COMMAND1
COMMAND2
COMMAND3
DAISY-CHAIN MODE
FROM ONE ADC TO
VALID DATA ADC1
DATA IS SHIFTED
THE NEXT ONE
SET CHANNEL
COMMAND2
SHIFTED INTO THE ADC1 INTERNAL REGISTER, IT
CONTAINS CHANNEL FOR NEXT CONVERSION ON ADC1
FOR ADC2,
SHIFTED INTO THE ADC2 INTERNAL REGISTER, IT
CONTAINS CHANNEL FOR NEXT CONVERSION ON ADC2
10
CH
10
≠
12
STY
13
SHIFTED INTO THE ADC1 INTERNAL REGISTER,
THIS DATA WILL BE EVENTUALLY LOST
CS HIGH BETWEEN THE
1
1
10TH–13TH SCLK
CHANGE MODE
FALLING EDGE
SET CHANNEL
(0, 0, CHN = STY, VALID DATA ADC1)
DON'T CARE
DON'T CARE
0, 0, CHN = MOD, VALID DATA ADC1
0, 0, CHN = MOD, VALID DATA ADC2
COMMAND1
0, 0, CHN
FOR ADC1,
(0, 0, CHN
0, 0, CHN
NORMAL CONVERSION
COMMAND3 WITH CHN
DAISY-CHAIN CYCLE
SHIFTED INTO THE ADC2
≠
≠
≠
DON'T CARE
MOD, VALID DATA ADC2
MOD, VALID DATA ADC1
INTERNAL REGISTER
STY, VALID DATA ADC1)
10
CONVERSION ON THE
AD7912/AD7922
NORMAL MODE
TWO DEVICES
12
DON'T CARE
DON'T CARE
≠
STY
14
16
16