EVAL-AD7689EDZ Datasheet, PDF (10/32 Pages) Analog Devices – 16-Bit, 4-Channel/8-Channel, 250 kSPS PulSAR ADC

AD7682/AD7689
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
Data Sheet
VDD 1
REF 2
REFIN 3
GND 4
GND 5
PIN 1
INDICATOR
AD7682
TOP VIEW
(Not to Scale)
15 VIO
14 SDO
13 SCK
12 DIN
11 CNV
VDD 1
REF 2
REFIN 3
GND 4
GND 5
PIN 1
INDICATOR
AD7689
TOP VIEW
(Not to Scale)
15 VIO
14 SDO
13 SCK
12 DIN
11 CNV
NOTES
1. NC = NO CONNECT.
2. THE EXPOSED PAD IS NOT CONNECTED
INTERNALLY. FOR INCREASED
RELIABILITY OF THE SOLDER JOINTS, IT
IS RECOMMENDED THAT THE PAD BE
SOLDERED TO THE SYSTEM
GROUND PLANE.
Figure 4. AD7682 Pin Configuration
NOTES
1. THE EXPOSED PAD IS NOT CONNECTED
INTERNALLY. FOR INCREASED
RELIABILITY OF THE SOLDER JOINTS, IT
IS RECOMMENDED THAT THE PAD BE
SOLDERED TO THE SYSTEM
GROUND PLANE.
Figure 5. AD7689 Pin Configuration
Table 7. Pin Function Descriptions
AD7682
AD7689
Pin No. Mnemonic Mnemonic
1, 20 VDD
VDD
2
REF
REF
3
REFIN
REFIN
4, 5
GND
6
NC
7
IN2
8
NC
9
IN3
10
COM
11
CNV
12
DIN
13
SCK
GND
IN4
IN5
IN6
IN7
COM
CNV
DIN
SCK
Type ¹
P
AI/O
AI/O
P
AI
AI
AI
AI
AI
DI
DI
DI
Description
Power Supply. Nominally 2.5 V to 5.5 V when using an external reference and decoupled
with 10 μF and 100 nF capacitors.
When using the internal reference for a2.5 V output, the minimum should be 3.0 V.
When using the internal reference for 4.096 V output, the minimum should be 4.6 V.
Reference Input/Output. See the Voltage Reference Output/Input section.
When the internal reference is enabled, this pin produces a selectable system reference of
2.5 V or 4.096 V.
When the internal reference is disabled and the buffer is enabled, REF produces a
buffered version of the voltage present on the REFIN pin (VDD − 0.5 V maximum), which
is useful when using low cost, low power references.
For improved drift performance, connect a precision reference to REF (0.5 V to VDD).
For any reference method, this pin needs decoupling with an external 10 μF capacitor
connected as close to REF as possible. See the Reference Decoupling section.
Internal Reference Output/Reference Buffer Input. See the Voltage Reference
Output/Input section.
When using the internal reference, the internal unbuffered reference voltage is present
and needs decoupling with a 0.1 μF capacitor.
When using the internal reference buffer, apply a source between 0.5 V and (VDD − 0.5 V)
that is buffered to the REF pin, as described in the REF pin description.
Power Supply Ground.
AD7682: no connection.
AD7689: Analog Input Channel 4.
AD7682: Analog Input Channel 2.
AD7689: Analog Input Channel 5.
AD7682: no connection.
AD7689: Analog Input Channel 6.
AD7682: Analog Input Channel 3.
AD7689: Analog Input Channel 7.
Common Channel Input. All input channels, IN[7:0], can be referenced to a common-
mode point of 0 V or VREF/2 V.
Conversion Input. On the rising edge, CNV initiates the conversion. During conversion, if
CNV is held low, the busy indictor is enabled.
Data Input. This input is used for writing to the 14-bit configuration register. The
configuration register can be written to during and after conversion.
Serial Data Clock Input. This input is used to clock out the data on SDO and clock in data
on DIN in an MSB first fashion.
Rev. D | Page 10 of 32