AD7787 Analog Devices, AD7787 Datasheet - Page 16

• Manufacturer Part Number: AD7787
• Description: Low Power, 2-Channel 24-Bit Sigma-Delta ADC
• Manufacturer: Analog Devices

Specifications of AD7787

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

AD7787
Single Conversion Mode
In single conversion mode, the AD7787 is placed in shutdown
mode between conversions. When a single conversion is
initiated by setting MD1 to 1 and MD0 to 0 in the mode
register, the AD7787 powers up, performs a single conversion,
and then returns to shutdown mode. When a single conversion
is initiated, the AD7787’s oscillator requires 1 ms to power up
and settle. The AD7787 then performs a conversion which
requires 2 × t
being performed and goes low to indicate the completion of the
conversion. When the data word has been read from the data
register, DOUT/ RDY goes high. If CS is low, DOUT/ RDY
remains high until another conversion is initiated 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 is high while the conversion is
Figure 14. Continuous Conversion
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Continuous Conversion Mode
This is the default power-up mode. The AD7787 will
continuously converts with the RDY pin in the status register
going low each time a conversion is complete. If CS is low, the
DOUT/ RDY line also goes low when a conversion is complete.
To read a conversion, the user can write to the communications
register, indicating that the next operation is a read of the data
register. The digital conversion is placed on the DOUT/ RDY
pin as soon as SCLK pulses are applied to the ADC.
DOUT/ RDY returns 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 completion of the next conversion or the new conversion
word is lost.
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