ADA4841-X AD [Analog Devices], ADA4841-X Datasheet - Page 12

• Manufacturer Part Number: ADA4841-X
• Manufacturer: AD [Analog Devices]

AD7689
TRANSFER FUNCTIONS
With the inputs configured for unipolar range (single ended,
COM with ground sense, or paired differentially with IN- as
ground sense), the data output is straight binary.
With the inputs configured for bipolar range (COM = V
paired differentially with IN- = V
two’s complement.
The ideal transfer characteristic for the AD7689 is shown in
Figure 12 and Table 8 for both unipolar and bipolar ranges with
the internal 4.096V reference.
Table 8. Output Codes and Ideal Input Voltages
Description
FSR − 1 LSB
Midscale + 1 LSB
Midscale
Midscale − 1 LSB
−FSR + 1 LSB
−FSR
1
2
3
4
TYPICAL CONNECTION DIAGRAM
Figure 13 shows an example of the recommended connection
diagram for the AD7689 when multiple supplies are available.
With COM or IN- = 0 V or all INx referenced to GND.
With COM or IN- = V
This is also the code for an overranged analog input ((IN+) − (IN-) , or COM, above V
This is also the code for an underranged analog input ((IN+) − (IN-), or COM, below V
REF
/2.
Unipolar Analog Input
V
4.095938 V
2.048063 V
2.048 V
2.047938 V
62.5 μV
0 V
REF
0 TO V
0 TO V
ADA4841-x
ADA4841-x
= 4.096 V
V
0 V or
REF
1
2
3
4
INTERNAL REFERNCE SHOWN. SEE REFERENCE SECTION FOR REFERENCE SELECTION.
C
SEE DRIVER AMPLIFIER SECTION FOR ADDITIONAL RECOMMENDED AMPLIFIERS.
SEE THE DIGITAL INTERFACE SECTION FOR CONFIGURING AND READING CONVERSION DATA.
REF
REF
REF
/2
IS USUALLY A 22µF CERAMIC CAPACITOR (X5R).
REF
3
3
/2), the data outputs are
V–
V+
V–
V+
1
Figure 13. Typical Application Diagram with Multiple Supplies
Digital Output
Code (Straight
Binary Hex)
0xFFFF
0x8001
0x8000
0x7FFF
0x0001
0x0000
22µF
2
3
COM
4
INn
IN0
REF
REF
100nF
/2, or
Rev. PrC | Page 12 of 20
REFIN
AD7689
REF
GND
− V
VDD
Bipolar Analog Input
V
+2.047938 V
62.5 μV
0
-62.5 μV
-2.047938 V
-2.048 V
GND
GND
REF
100nF
).
).
= 4.096 V
5V
2’s COMP STRAIGHT
011...111
011...110
011...101
100...010
100...001
100...000
VIO
SDO
SCK
CNV
DIN
100nF
1.8V TO VDD
111...111
111...110
111...101
000...010
000...001
000...000
BINARY
2
Figure 12. ADC Ideal Transfer Function
–FSR + 0.5LSB
–FSR
Preliminary Technical Data
3-WIRE INTERFACE
Digital Output
Code (2’s Complement
Hex)
0x7FFF
0x0001
0x0000
0xFFFF
0x8001
0x8000
–FSR + 1LSB
3
4
4
ANALOG INPUT
+FSR – 1.5LSB
+FSR – 1LSB