AD7991 Analog Devices, AD7991 Datasheet - Page 23

• Manufacturer Part Number: AD7991
• Description: 4-Channel, 12-Bit ADC with I2C Compatible Interface in 8-Lead SOT-23
• Manufacturer: Analog Devices

Specifications of AD7991

• Resolution (bits): 12bit
• # Chan: 4
• Sample Rate: 140kSPS
• Interface: I²C/Ser 2-Wire
• Analog Input Type: SE-Uni
• Ain Range: Uni (Vref),Uni Vdd
• Adc Architecture: SAR
• Pkg Type: SOT

WRITING TO THE AD7991/AD7995/AD7999
By default, each part operates in read-only mode and all four chan-
nels are selected as enabled in the configuration register. To write
to the AD7991/AD7995/AD7999 configuration register, the user
must first address the device.
SCL
SDA
START BY
MASTER
0
1
1
SERIAL BUS ADDRESS BYTE
0
Figure 24. Writing to the AD7991/AD7995/AD7999 Configuration Register
1
FRAME 1
0
0
A0
Rev. B | Page 23 of 28
R/W
ACK BY
ADC
9
D7
1
The configuration register is an 8-bit register; therefore, only
one byte of data can be written to this register. However, writing
a single byte of data to this register consists of writing the serial
bus write address, followed by the data byte written (see Figure 24).
D6
CONFIGURATION REGISTER BYTE
D5
D4
D3
D2
AD7991/AD7995/AD7999
D1
D0
ACK BY
ADC
9
STOP