AD7795 Analog Devices, AD7795 Datasheet - Page 23

• 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

Bit No.
CON5
CON4
CON3 to
CON0
Mnemonic
REF_DET
BUF
CH3 to CH0
Description
Enables the reference detect function. When set, the NOXREF bit in the status register indicates when the
external reference being used by the ADC is open circuit or less than 0.5 V. When cleared, the reference
detect function is disabled.
Configures the ADC for buffered or unbuffered mode of operation. If cleared, the ADC operates in
unbuffered mode, lowering the power consumption of the device. If set, the ADC operates in buffered
mode, allowing the user to place source impedances on the front end without contributing gain errors to
the system. For gains of 1 and 2, the buffer can be enabled or disabled. For higher gains, the buffer is
automatically enabled. With the buffer disabled, the voltage on the analog input pins can be from 30 mV
below GND to 30 mV above AV
on any input pin must be limited to 100 mV within the power supply rails.
Channel Select Bits.
Written by the user to select the active analog input channel to the ADC.
CH3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
CH2
0
0
0
0
1
1
1
1
0
0
0
1
1
1
1
CH1
0
0
1
1
0
0
1
1
0
0
1
0
0
1
1
CH0
0
1
0
1
0
1
0
1
0
1
1
0
1
0
1
Rev. D | Page 23 of 36
DD
. When the buffer is enabled, it requires some headroom so the voltage
Channel
AIN1(+)/AIN1(−)
AIN2(+)/AIN2(−)
AIN3(+)/AIN3(−)
AIN4(+)/AIN4(−)
AIN5(+)/AIN5(−)
AIN6(+)/AIN6(−)
Temp Sensor
AV
AIN1(−)/AIN1(−)
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
DD
Monitor
Calibration Pair
0
1
2
3
3
3
Automatically selects the internal 1.17 V reference
and sets the gain to 1
Automatically selects the internal 1.17 V reference
and sets the gain to 1/6
0
AD7794/AD7795