ad7650astrl Analog Devices, Inc., ad7650astrl Datasheet - Page 11

• Manufacturer Part Number: ad7650astrl
• Description: 16-bit, 570 Ksps Low Cost Cmos Adc
• Manufacturer: Analog Devices, Inc.

Transfer Functions
Using the OB/2C digital input, the AD7650 offers two output
codings: straight binary and two’s complement. The LSB size is
V
acteristic for the AD7650 is shown in Figure 4 and Table I.
REF
/65536, which is about 38.15 µV. The ideal transfer char-
ANALOG INPUT
111...111
111...110
111...101
000...010
000...001
000...000
(0V TO 2.5V)
ANALOG
SUPPLY
0.5 LSB
0V
2.5V REF
(5V)
NOTE 1
NOTE 2
1 LSB = V
1 LSB
NOTES
1. THE ADR421 IS RECOMMENDED WITH C
2. THE AD8021 IS RECOMMENDED WITH A COMPENSATION CAPACITOR C
3. OPTIONAL LOW JITTER CNVST.
U1
+
REF
C
C
/65536
+
REF
ANALOG INPUT
C
15
10 F
1
1 F
4.7nF
V
100nF
REF
REF
REFGND
IN+
IN–
AVDD
– 1.5 LSB
V
REF
PD
100
AGND
– 1 LSB
RESET
REF
+
= 47 F.
10 F
AD7650
DGND
100nF
CS
Description
FSR – 1 LSB
FSR – 2 LSB
Midscale + 1 LSB
Midscale
Midscale – 1 LSB
–FSR + 1 LSB
–FSR
NOTES
1
2
TYPICAL CONNECTION DIAGRAM
Figure 5 shows a typical connection diagram for the AD7650.
This is also the code for overrange analog input (V
This is also the code for underrange analog input (V
DVDD
Table I. Output Codes and Ideal Input Voltages
OVDD
RD
C
= 10pF, TYPE CERAMIC NPO.
SER/PAR
IMPULSE
OGND
SDOUT
CNVST
OB/2C
WARP
SCLK
BUSY
100nF
Analog
Input
2.499962 V
2.499923 V
1.250038 V
1.25 V
1.249962 V
38 µV
0 V
+
NOTE 3
D
DVDD
10 F
SERIAL
PORT
CLOCK
Digital Output Code (Hex)
Straight
Binary
FFFF
FFFE
8001
8000
7FFF
0001
0000
DIGITAL SUPPLY
(3.3V OR 5V)
IN+
2
1
– V
IN+
IN–
C/ P/DSP
below V
above V
AD7650
Two’s
Complement
7FFF
7FFE
0001
0000
FFFF
8001
8000
IN–
REF
).
2
– V
1
REFGND
).