AD7794/AD7795

Rev. D | Page 23 of 36

Bit No.

Mnemonic

Description

CON5

REF_DET

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.

CON4

BUF

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

on any input pin must be limited to 100 mV within the power supply rails.

CON3 to

CON0

CH3 to CH0

Channel Select Bits.

Written by the user to select the active analog input channel to the ADC.

CH3

CH2

CH1

CH0

Channel

Calibration Pair

0

0

0

0

AIN1(+)/AIN1(−)

0

0

0

0

1

AIN2(+)/AIN2(−)

1

0

0

1

0

AIN3(+)/AIN3(−)

2

0

0

1

1

AIN4(+)/AIN4(−)

3

0

1

0

0

AIN5(+)/AIN5(−)

3

0

1

0

1

AIN6(+)/AIN6(−)

3

0

1

1

0

Temp Sensor

Automatically selects the internal 1.17 V reference

and sets the gain to 1

0

1

1

1

Automatically selects the internal 1.17 V reference

and sets the gain to 1/6

1

0

0

0

AIN1(−)/AIN1(−)

0

1

0

0

1

Reserved

1

0

1

1

Reserved

1

1

0

0

Reserved

1

1

0

1

Reserved

1

1

1

0

Reserved

1

1

1

1

Reserved