EVAL-AD7679CBZ Analog Devices Inc, EVAL-AD7679CBZ Datasheet - Page 16

• Manufacturer Part Number: EVAL-AD7679CBZ
• Description: BOARD EVALUATION FOR AD7679
• Manufacturer: Analog Devices Inc
• Series: PulSAR®r

Specifications of EVAL-AD7679CBZ

• Number Of Adc's: 1
• Number Of Bits: 18
• Sampling Rate (per Second): 570k
• Data Interface: Serial, Parallel
• Inputs Per Adc: 1 Differential
• Input Range: ±VREF
• Power (typ) @ Conditions: 89mW @ 500kSPS
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Utilized Ic / Part: AD7679
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD7679
Transfer Functions
Except in 18-bit interface mode, the AD7679 offers straight
binary and twos complement output coding when using OB/ 2C .
See
Figure 24
ANALOG INPUT+
ANALOG INPUT–
111...111
111...110
111...101
000...010
000...001
000...000
ADR421
2.5V REF
NOTE 1
–FS + 0.5 LSB
and
–FS
Figure 24. ADC Ideal Transfer Function
ANALOG
SUPPLY
Table 8
NOTE 3
NOTES
1. SEE VOLTAGE REFERENCE INPUT SECTION.
2. OPTIONAL CIRCUITRY FOR HARDWARE GAIN CALIBRATION.
3.THE AD8021 IS RECOMMENDED. SEE DRIVER AMPLIFIER CHOICE SECTION.
4. SEE ANALOG INPUTS SECTION.
5. OPTION, SEE POWER SUPPLY SECTION.
6. OPTIONAL LOW JITTER CNVST, SEE CONVERSION CONTROL SECTION.
NOTE 3
100nF
AD8021
(5V)
–FS + 1 LSB
1MΩ
AD8021
NOTE 2
–
+
–
+
U1
for the ideal transfer characteristic.
U2
ANALOG INPUT
50kΩ
C
C
C
C
30Ω
100nF
30Ω
+
Figure 25. Typical Connection Diagram (Internal Reference Buffer, Serial Interface)
NOTE 1
47μF
C
10μF
REF
NOTE 4
NOTE 4
2.7nF
2.7nF
+FS – 1.5 LSB
100nF
REFBUFIN
IN+
IN–
REF
REFGND
+FS – 1 LSB
AVDD
03085-0-026
NOTE 5
20Ω
AGND
Rev. A | Page 16 of 28
+
10μ F
AD7679
DGND
100nF
Table 8. Output Codes and Ideal Input Voltages
Description
FSR –1 LSB
FSR – 2 LSB
Midscale +
1 LSB
Midscale
Midscale –
1 LSB
–FSR + 1 LSB
–FSR
1
2
DVDD
DVDD
This is also the code for overrange analog input (V
above V
This is also the code for underrange analog input (V
below –V
REF
OVDD
REF
– V
+ V
REFGND
REFGND
SDOUT
MODE1
MODE0
PDBUF
CNVST
OGND
RESET
OB/2C
BUSY
SCLK
).
).
4.095962 V
4.095924 V
–31.25 μV
-4.095962 V
-4.096 V
Analog Input
V
31.25 μV
0 V
CS
RD
PD
100nF
REF
= 4.096 V
+
NOTE 6
50Ω
DVDD
10μ F
SERIAL PORT
DIGITAL SUPPLY
(3.3V OR 5V)
D
Straight
Binary
(Hex)
3FFFF
3FFFE
20001
20000
1FFFF
00001
00000
CLOCK
IN+
1
2
IN+
– V
– V
μC/μP/DSP
IN–
IN–
Twos
Complement
(Hex)
1FFFF
1FFFE
00001
00000
3FFFF
20001
20000
03085-0-027
1
2