EVAL-AD7687CB Analog Devices Inc, EVAL-AD7687CB Datasheet - Page 14

• Manufacturer Part Number: EVAL-AD7687CB
• Description: BOARD EVAL FOR AD7687
• Manufacturer: Analog Devices Inc
• Series: PulSAR®r

Specifications of EVAL-AD7687CB

• Number Of Adc's: 1
• Number Of Bits: 16
• Sampling Rate (per Second): 250k
• Data Interface: Serial
• Inputs Per Adc: 1 Differential
• Input Range: ±VREF
• Power (typ) @ Conditions: 4mW @ 5 V, 100kSPS
• Voltage Supply Source: Single
• Operating Temperature: -40°C ~ 85°C
• Utilized Ic / Part: AD7687
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: Q2106448

AD7687
Transfer Functions
The ideal transfer characteristic for the AD7687 is shown in
Figure 26 and Table 9.
Table 9. Output Codes and Ideal Input Voltages
Description
FSR – 1 LSB
Midscale + 1 LSB
Midscale
Midscale – 1 LSB
–FSR + 1 LSB
–FSR
1.
2.
V
REF
This is also the code for an overranged analog input (V
This is also the code for an underranged analog input (V
V
GND
+ V
011...111
011...110
011...101
100...010
100...001
100...000
).
GND
).
–FSR + 0.5 LSB
–FSR
Figure 26. ADC Ideal Transfer Function
–FSR + 1 LSB
Analog Input
V
+4.999847 V
+152.6 μV
0 V
−152.6 μV
−4.999847 V
−5 V
REF
0 TO VREF
VREF TO 0
= 5 V
ANALOG INPUT
1
2
3
4
5
SEE REFERENCE SECTION FOR REFERENCE SELECTION.
C
SEE DRIVER AMPLIFIER CHOICE SECTION.
OPTIONAL FILTER. SEE ANALOG INPUT SECTION.
SEE DIGITAL INTERFACE FOR MOST CONVENIENT INTERFACE MODE.
3
3
REF
≤–2V
≤–2V
≥7V
≥7V
≥7V
IS USUALLY A 10μF CERAMIC CAPACITOR (X5R).
Digital Output Code Hexa
7FFF
0001
0000
FFFF
8001
8000
+FSR – 1.5 LSB
1
2
REF
Figure 27. Typical Application Diagram with Multiple Supplies
2.7nF
4
2.7nF
4
33Ω
33Ω
IN+
1
IN+
+FSR – 1 LSB
− V
− V
IN−
10μF
IN−
above V
below −
2
IN+
IN–
REF
Rev. A | Page 14 of 28
−
GND
REF
AD7687
VDD
TYPICAL CONNECTION DIAGRAM
Figure 27 shows an example of the recommended connection
diagram for the AD7687 when multiple supplies are available.
VIO
SCK
SDO
CNV
SDI
100nF
100nF
3- OR 4-WIRE INTERFACE
5V
1.8V TO VDD
5