AD7734 Analog Devices, AD7734 Datasheet - Page 15

• Manufacturer Part Number: AD7734
• Manufacturer: Analog Devices

Specifications of AD7734

• Resolution (bits): 24bit
• # Chan: 4
• Sample Rate: 3.05MSPS
• Interface: Ser,SPI
• Analog Input Type: SE-Bip,SE-Uni
• Ain Range: Bip 10V,Bip 5.0V,Uni 10V,Uni 5.0V
• Adc Architecture: Sigma-Delta
• Pkg Type: SOP

Register Access
The AD7734 is configurable through a series of registers. Some
of them configure and control general AD7734 features, while
others are specific to each channel. The register data widths
vary from 8 bits to 24 bits. All registers are accessed through the
communications register, i.e., any communication to the
AD7734 must start with a write to the communications register
specifying which register will be subsequently read or written.
Communications Register
8 Bits, Write-Only Register, Address 00h
All communications to the part must start with a write
operation to the communications register. The data written to
Bit
Mnemonic
Bit
7
6
5–0
Table 14.
Bit 2
0
0
0
0
Mnemonic
0
R/W
Address
Bit 1
0
0
1
1
Bit 0
0
1
0
1
Bit 7
0
Description
This bit must be 0 for proper operation.
A 0 in this bit indicates that the next operation will be a write to a specified register. A 1 in this bit indicates
that the next operation will be a read from a specified register.
Address specifying to which register the read or write operation will be directed. For channel specific registers,
two LSBs, i.e., Bit 1 and Bit 0, specify the channel number. When the subsequent operation writes to the Mode
register, two LSBs specify the channel selected for operation determined by the mode register value (see
Table 14).
Channel
0
1
2
3
Bit 6
R/W
Input
AIN0
AIN1
AIN2
AIN3
Bit 5
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Bit 4
the communications register determines whether the
subsequent operation will be a read or write and to which
register this operation will be directed. The digital interface
defaults to expect write operation to the communications
register after power-on, after reset, or after the subsequent read
or write operation to the selected register is complete. If the
interface sequence is lost, the part can be reset by writing at
least 32 serial clock cycles with DIN high and CS low. (Note that
all of the parts, including the modulator, filter, interface, and all
registers are reset in this case.) Remember to keep DIN low
while reading 32 bits or more either in continuous read mode or
with the DUMP bit and “24/16” bit in the mode register set.
Bit 3
6-Bit Register Address
Bit 2
Bit 1
AD7734
Bit 0