AD7795 Analog Devices, AD7795 Datasheet - Page 24

• Manufacturer Part Number: AD7795
• Description: 6-Channel, Low Noise, Low Power, 16-Bit Sigma Delta ADC with On-Chip In-Amp and Reference
• Manufacturer: Analog Devices

Specifications of AD7795

• Resolution (bits): 16bit
• # Chan: 6
• Sample Rate: n/a
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni
• Ain Range: (2Vref/PGA Gain) p-p
• Adc Architecture: Sigma-Delta
• Pkg Type: SOP

AD7794/AD7795
DATA REGISTER
RS2, RS1, RS0 = 0, 1, 1; Power-On/Reset =
0x0000(AD7795), 0x000000 (AD7794)
The conversion result from the ADC is stored in this data
register. This is a read-only register. On completion of a read
operation from this register, the RDY bit/pin is set.
ID REGISTER
RS2, RS1, RS0 = 1, 0, 0; Power-On/Reset = 0xXF
The identification number for the AD7794/AD7795 is stored in
the ID register. This is a read-only register.
IO7
0(0)
Table 21. IO Register Bit Designations
Bit No.
IO7
IO6
IO5 to IO4
IO3 to IO2
IO3 to IO2
IO6
IOEN(0)
0
Mnemonic
IOEN
IO2DAT/IO1DAT
IEXCDIR1 to IEXCDIR0
IEXCEN1 to IEXCEN0
IO5
IO2DAT(0)
Description
This bit must be programmed with a Logic 0 for correct operation.
Configures Pin AIN6(+)/P1 and Pin AIN6(−)/P2 as analog input pins or digital output pins. When this
bit is set, the pins are configured as Digital Output Pin P1 and Digital Output Pin P2. When this bit is
cleared, these pins are configured as Analog Input Pin AIN6(+) and Analog Input Pin AIN6(−).
P2/P1 Data. When IOEN is set, the data for Digital Output Pin P1 and Digital Output Pin P2 is written
to Bit IO2DAT and Bit IO1DAT.
Direction of Current Sources Select Bits.
IEXCDIR1
0
0
1
1
These bits are used to enable and disable the current sources. They also select the value of the
excitation currents.
IEXCEN1
0
0
1
1
IO4
IO1DAT(0)
IEXCDIR0
0
1
0
1
IEXCEN0
0
1
0
1
Rev. D | Page 24 of 36
IO3
IEXCDIR1(0)
Current Source Direction
Current Source IEXC1 connected to Pin IOUT1. Current Source IEXC2
connected to Pin IOUT2.
Current Source IEXC1 connected to Pin IOUT2. Current Source IEXC2
connected to Pin IOUT1.
Both current sources connected to Pin IOUT1. Permitted only when the
current sources are set to 10 μA or 210 μA.
Both current sources connected to Pin IOUT2. Permitted only when the
current sources are set to 10 μA or 210 μA.
Current Source Value
Excitation currents disabled
10 μA
210 μA
1 mA
IO REGISTER
RS2, RS1, RS0 = 1, 0, 1; Power-On/Reset = 0x00
The IO register is an 8-bit read/write register that is used
to enable the excitation currents and select the value of the
excitation currents.
Table 21 outlines the bit designations for the IO register. IO0
through IO7 indicate the bit locations. IO denotes that the bits
are in the IO register. IO7 denotes the first bit of the data
stream. The number in brackets indicates the power-on/reset
default status of that bit.
IO2
IEXCDIR0(0)
IO1
IEXCEN1(0)
IO0
IEXCEN0(0)