EVAL-AD7686CB Analog Devices Inc, EVAL-AD7686CB Datasheet - Page 13

• Manufacturer Part Number: EVAL-AD7686CB
• Description: BOARD EVALUATION FOR AD7686
• Manufacturer: Analog Devices Inc
• Series: PulSAR®r

Specifications of EVAL-AD7686CB

• Number Of Adc's: 1
• Number Of Bits: 16
• Sampling Rate (per Second): 500k
• Data Interface: Serial
• Inputs Per Adc: 1 Differential
• Input Range: ±VREF
• Power (typ) @ Conditions: 15mW @ 500kSPS, 5 V
• Voltage Supply Source: Single
• Operating Temperature: -40°C ~ 85°C
• Utilized Ic / Part: AD7686
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Transfer Functions
The ideal transfer characteristic for the AD7686 is shown in
Figure 25 and Table 7.
000...010
000...001
000...000
111...110
111...101
111...111
–FSR + 0.5 LSB
–FSR
Figure 25. ADC Ideal Transfer Function
–FSR + 1 LSB
0 TO VREF
ANALOG INPUT
1
2
3
4
5
SEE THE VOLTAGE REFERENCE INPUT SECTION FOR REFERENCE SELECTION.
C
SEE DRIVER AMPLIFIER CHOICE SECTION.
OPTIONAL FILTER. SEE ANALOG INPUT SECTION.
SEE DIGITAL INTERFACE SECTION FOR MOST CONVENIENT INTERFACE MODE.
3
REF
≤–2V
≥7V
≥7V
+FSR – 1.5 LSB
IS USUALLY A 10µF CERAMIC CAPACITOR (X5R).
Figure 26. Typical Application Diagram with Multiple Supplies
REF
4
2.7nF
+FSR – 1 LSB
33Ω
1
10µF
2
IN+
IN–
Rev. B | Page 13 of 28
GND
REF
AD7686
VDD
Table 7. Output Codes and Ideal Input Voltages
Description
FSR – 1 LSB
Midscale + 1 LSB
Midscale
Midscale – 1 LSB
–FSR + 1 LSB
–FSR
TYPICAL CONNECTION DIAGRAM
Figure 26 shows an example of the recommended connection
diagram for the AD7686 when multiple supplies are available.
1
2
This is also the code for an overranged analog input (V
This is also the code for an underranged analog input (V
VIO
SCK
SDO
CNV
SDI
100nF
100nF
3- OR 4-WIRE INTERFACE
Analog Input
V
4.999924 V
2.500076 V
2.5 V
2.499924 V
76.3 μV
0 V
5V
1.8V TO VDD
REF
= 5 V
Digital Output Code
Hexadecimal
FFFF
8001
8000
7FFF
0001
0000
5
1
2
IN+
− V
IN+
IN−
− V
above V
AD7686
IN−
below V
REF
− V
GND
GND
).
).