AD7791 Analog Devices, AD7791 Datasheet - Page 16

• Manufacturer Part Number: AD7791
• Description: 24-Bit, Single-Channel, Ultra Low Power, Sigma Delta A/D Converter
• Manufacturer: Analog Devices

Specifications of AD7791

• Resolution (bits): 24bit
• # Chan: 1
• Sample Rate: n/a
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni
• Ain Range: (2Vref) p-p
• Adc Architecture: Sigma-Delta
• Pkg Type: SOP

AD7791
Single Conversion Mode
In single conversion mode, the AD7791 is placed in shutdown
mode between conversions. When a single conversion is initi-
ated by setting MD1 to 1 and MD0 to 0 in the mode register, the
AD7791 powers up, performs a single conversion, and then
returns to shutdown mode. A conversion will require a time
period of 2 × t
pletion of a conversion. When the data-word has been read
from the data register, DOUT/ RDY will go high. If CS is low,
DOUT/ RDY will remain high until another conversion is initi-
ated and completed. The data register can be read several times,
if required, even when DOUT/ RDY has gone high.
DOUT/RDY
SCLK
DIN
CS
ADC
. DOUT/ RDY goes low to indicate the com-
Figure 14. Continuous Conversion
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DATA
Continuous Conversion Mode
This is the default power-up mode. The AD7791 will continu-
ously convert, the RDY pin in the status register going low each
time a conversion is complete. If CS is low, the DOUT/ RDY line
will also go low when a conversion is complete. To read a con-
version, the user can write to the communications register,
indicating that the next operation is a read of the data register.
The digital conversion will be placed on the DOUT/ RDY pin as
soon as SCLK pulses are applied to the ADC. DOUT/ RDY will
return high when the conversion is read. The user can read this
register additional times, if required. However, the user must
ensure that the data register is not being accessed at the comple-
tion of the next conversion or else the new conversion word will
be lost.
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DATA
04227-0-009