AD7988-5 Analog Devices, AD7988-5 Datasheet - Page 15

• Manufacturer Part Number: AD7988-5
• Description: 16-Bit, 500ksps, Ultra Lower Power 16 bit SAR ADC
• Manufacturer: Analog Devices

Specifications of AD7988-5

• Resolution (bits): 16bit
• # Chan: 1
• Sample Rate: 500kSPS
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni
• Ain Range: Uni 5.0V
• Adc Architecture: SAR
• Pkg Type: SOP

Data Sheet
Transfer Functions
The ideal transfer characteristic for the
Figure 30 and Table 7.
000 ... 010
000 ... 001
000 ... 000
111 ... 101
111 ... 111
111 ... 110
–FSR
–FSR + 0.5LSB
1
2
3
4
5
0V TO V
SEE THE VOLTAGE REFERENCE INPUT SECTION FOR REFERENCE SELECTION.
C
SEE THE DRIVER AMPLIFIER CHOICE SECTION.
OPTIONAL FILTER. SEE THE ANALOG INPUTS SECTION.
SEE THE DIGITAL INTERFACE SECTION FOR THE MOST CONVENIENT INTERFACE MODE.
REF
Figure 30. ADC Ideal Transfer Function
–FSR + 1LSB
IS USUALLY A 10µF CERAMIC CAPACITOR (X5R).
REF
V+
V–
ANALOG INPUT
3
V+
AD7988-x
+FSR – 1.5 LSB
4
Figure 31. Typical Application Diagram with Multiple Supplies
REF
20Ω
2.7nF
1
+FSR – 1 LSB
is shown in
10µF
2
Rev. A | Page 15 of 24
IN+
IN–
GND
REF
AD7988-1/
AD7988-5
Table 7. Output Codes and Ideal Input Voltages
Description
FSR – 1 LSB
Midscale + 1 LSB
Midscale
Midscale – 1 LSB
–FSR + 1 LSB
–FSR
1
2
TYPICAL CONNECTION DIAGRAM
Figure 31 shows an example of the recommended connection
diagram for the
This is also the code for an underranged analog input (V
This is also the code for an overranged analog input (V
VDD
VIO
SDO
SCK
CNV
SDI
AD7988-x
V
4.999924 V
2.500076 V
2.5 V
2.499924 V
76.3 µV
0 V
REF
100nF
100nF
= 5 V
when multiple supplies are available.
2.5V
1.8V TO 5.5V
3- OR 4-WIRE INTERFACE
AD7988-1/AD7988-5
Analog Input
Digital Output Code (Hex)
FFFF
8001
8000
7FFF
0001
0000
1
2
IN+
− V
IN+
IN−
− V
above V
5
IN−
below V
REF
− V
GND
GND
).
).