AD7660 Analog Devices, AD7660 Datasheet - Page 11

• Manufacturer Part Number: AD7660
• Manufacturer: Analog Devices

Specifications of AD7660

• Resolution (bits): 16bit
• # Chan: 1
• Sample Rate: 100kSPS
• Interface: Par,Ser,SPI
• Analog Input Type: Diff-Uni
• Ain Range: (Vref) p-p
• Adc Architecture: SAR
• Pkg Type: CSP,QFP

Transfer Functions
Using the OB/2C digital input, the AD7660 offers two output
codings: straight binary and twos complement. The LSB size is
V
teristic for the AD7660 is shown in Figure 4 and Table II.
REV. D
REF
/65536, which is about 38.15 mV. The ideal transfer charac-
111...111
111...110
111...101
000...010
000...001
000...000
ANALOG INPUT
Figure 4. ADC Ideal Transfer Function
(0V TO 2.5V)
ANALOG
SUPPLY
0.5 LSB
0V
(5V)
2.5V REF
NOTE 1
1 LSB = V
1 LSB
NOTE 2
REF
/65536
ANALOG INPUT
NOTES
1. WITH THE AD780 OR THE ADR291 VOLTAGE REFERENCE, C
2. THE OP184 IS RECOMMENDED.
3. OPTIONAL LOW JITTER CNVST.
SEE VOLTAGE REFERENCE INPUT SECTION.
NOTE 1
10 F
C
U1
REF
V
REF
100nF
–1.5 LSB
Figure 5. Typical Connection Diagram
REF
REFGND
IN
INGND
AVDD
V
REF
PD
–1 LSB
AGND
100
RESET
10 F
–11–
AD7660
DGND
Description
FSR – 1 LSB
FSR – 2 LSB
Midscale + 1 LSB 1.250038 V 8001
Midscale
Midscale – 1 LSB 1.249962 V 7FFF
–FSR + 1 LSB
–FSR
NOTES
1
2
TYPICAL CONNECTION DIAGRAM
Figure 5 shows a typical connection diagram for the AD7660.
This is also the code for overrange analog input (V
This is also the code for underrange analog input (V
V
100nF
REF
– V
DVDD
Table II. Output Codes and Ideal Input Voltages
REFGND
REF
OVDD
IS 47 F,
).
SER/PAR
SDOUT
OGND
CNVST
Analog
Input
2.499962 V FFFF
2.499923 V FFFE
1.25 V
38 mV
0 V
OB/2C
SCLK
BUSY
CS
RD
100nF
NOTE 3
DVDD
10 F
D
Digital Output Code (Hex)
Straight
Binary
8000
0001
0000
SERIAL
PORT
CLOCK
2
1
DIGITAL SUPPLY
(3.3V OR 5V)
IN
IN
– V
below V
C/ P/DSP
INGND
AD7660
Twos
Complement
7FFF
7FFE
0001
0000
FFFF
8001
8000
above
INGND
2
1
).