AD7688 Analog Devices, AD7688 Datasheet - Page 7

• Manufacturer Part Number: AD7688
• Manufacturer: Analog Devices

Specifications of AD7688

• Resolution (bits): 16bit
• # Chan: 1
• Sample Rate: 500kSPS
• Interface: Ser,SPI
• Analog Input Type: Diff-Uni
• Ain Range: (2Vref) p-p
• Adc Architecture: SAR
• Pkg Type: CSP,SOP

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Table 7. Pin Function Descriptions
Pin No.
1
2
3
4
5
6
7
8
9
10
1
AI = Analog Input, DI = Digital Input, DO = Digital Output, P = Power, and N/A = not applicable.
Mnemonic
REF
VDD
IN+
IN−
GND
CNV
SDO
SCK
SDI
VIO
EPAD
Figure 5. 10-Lead MSOP Pin Configuration
GND
VDD
REF
IN+
IN–
1
2
3
4
5
(Not to Scale)
Type
AI
P
AI
AI
P
DI
DO
DI
DI
P
N/A
AD7688
TOP VIEW
1
Function
Reference Input Voltage. The REF range is from 0.5 V to VDD. It is referred to the GND pin. This pin should
be decoupled closely to the pin with a 10 μF capacitor.
Power Supply.
Differential Positive Analog Input.
Differential Negative Analog Input.
Power Supply Ground.
Convert Input. This input has multiple functions. On its leading edge, it initiates the conversions and
selects the interface mode, chain or CS . In CS mode, it enables the SDO pin when low. In chain mode, the
data should be read when CNV is high.
Serial Data Output. The conversion result is output on this pin. It is synchronized to SCK.
Serial Data Clock Input. When the part is selected, the conversion result is shifted out by this clock.
Serial Data Input. This input provides multiple features. It selects the interface mode of the ADC as follows:
Chain mode is selected if SDI is low during the CNV rising edge. In this mode, SDI is used as a data input to
daisy-chain the conversion results of two or more ADCs onto a single SDO line. The digital data level on
SDI is output on SDO with a delay of 16 SCK cycles.
CS mode is selected if SDI is high during the CNV rising edge. In this mode, either SDI or CNV can enable
the serial output signals when low, and if SDI or CNV is low when the conversion is complete, the BUSY
indicator feature is enabled.
Input/Output Interface Digital Power. Nominally at the same supply as the host interface (1.8 V, 2.5 V, 3 V,
or 5 V).
For the LFCSP package only, the exposed paddle must be connected to GND.
10
9
8
7
6
VIO
SDI
SCK
SDO
CNV
Rev. A | Page 7 of 28
Figure 6. 10-Lead QFN (LFCSP) Pin Configuration
GND
NOTES
1. FOR THE LFCSP PACKAGE ONLY,
VDD
REF
IN+
IN–
THE EXPOSED PADDLE MUST BE
CONNECTED TO GND.
1
2
3
4
5
(Not to Scale)
AD7688
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10 VIO
9 SDI
8 SCK
7 SDO
6 CNV
AD7688