AD7190 View Datasheet(PDF) - Analog Devices
Part Name
Description
Manufacturer
AD7190 Datasheet PDF : 40 Pages
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AD7190
CON23
Chop(0)
CON15
CH7(0)
CON7
Burn(0)
CON22
0(0)
CON14
CH6(0)
CON6
REFDET(0)
CON21
0(0)
CON13
CH5(0)
CON5
0(0)
CON20
REFSEL(0)
CON12
CH4(0)
CON4
BUF(1)
CON19
0(0)
CON11
CH3(0)
CON3
U/B (0)
CON18
0(0)
CON10
CH2(0)
CON2
G2(1)
CON17
0(0)
CON9
CH1(0)
CON1
G1(1)
CON16
(0)
CON8
CH0(1)
CON0
G0(1)
Table 19. Configuration Register Bit Designations
Bit Location
Bit Name
Description
CON23
Chop
Chop enable bit. When the chop bit is cleared, chop is disabled. When the chop bit is set, chop is
enabled. When chop is enabled, the offset and offset drift of the ADC are continuously minimized.
However, this increases the conversion time and settling time of the ADC. For example, when FS = 96
decimal and the sinc4 filter is selected, the conversion time with chop enabled equals 80 ms and the
settling time equals 160 ms. With chop disabled, higher conversion rates are allowed. For an FS word of
96 decimal and the sinc4 filter selected, the conversion time is 20 ms and the settling time is 80 ms.
However, at low gains, periodic calibrations may be required to remove the offset and offset drift.
CON22, CON21
These bits must be programmed with a Logic 0 for correct operation.
CON20
REFSEL
Reference select bits. The reference source for the ADC is selected using these bits.
REFSEL
Reference Voltage
0
External reference applied between REFIN1(+) and REFIN1(−).
1
External reference applied between the P1 and P0 pins.
CON19 to CON16
These bits must be programmed with a Logic 0 for correct operation.
CON15 to CON8 CH7 to CH0
Channel select bits. These bits are used to select which channels are enabled on the AD7190. See Table 20.
Several channels can be selected, and the AD7190 automatically sequences them. The conversion on
each channel requires the complete settling time.
CON7
Burn
When this bit is set to 1 by the user, the 500 nA current sources in the signal path are enabled. When
burn = 0, the burnout currents are disabled. The burnout currents can be enabled only when the buffer
is active and when chop is disabled.
CON6
REFDET
Enables the reference detect function. When set, the NOREF bit in the status register indicates when the
external reference being used by the ADC is open circuit or less than 0.5 V typically. The reference detect
circuitry only operates when the ADC is active.
CON5
This bit must be programmed with a Logic 0 for correct operation.
CON4
BUF
Configures the ADC for a buffered or an 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. With the buffer disabled, the voltage on the analog input pins can be from 50 mV below
GND to 50 mV above AVDD. When the buffer is enabled, it requires some headroom; therefore, the
voltage on any input pin must be limited to 250 mV within the power supply rails.
CON3
U/B
Polarity select bit. When this bit is set, unipolar operation is selected. When this bit is cleared, bipolar
operation is selected.
CON2 to CON0 G2 to G0
Gain select bits. Written by the user to select the ADC input range as follows:
G2
G1
G0
Gain
ADC Input Range (5 V Reference, Bipolar Mode)
0
0
0
1
+5 V
0
0
1
Reserved
0
1
0
Reserved
0
1
1
8
+625 mV
1
0
0
16
+312.5 mV
1
0
1
32
+156.2 mV
1
1
0
64
+78.125 mV
1
1
1
128
+39.06 mV
Rev. 0 | Page 23 of 40
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