EVAL-AD7719-EB Datasheet, PDF (2/21 Pages) Analog Devices – Evaluation Board for the AD7719, 16&24-Bit, Dual Sigma Delta ADC

EVAL-AD7719-EB
LINK AND SWITCH OPTIONS
There are fourteen link options which must be set for the required operating setup before using the evaluation
board. The functions of these link options are outlined below.
Link No. Function
LK1-LK6 These links are in series with the AIN1 through AIN6 analog inputs respectively.
With these links in place, the analog inputs on the relevant SKT input is connected directly to the
respective AIN input on the part. For example, with LK1 in place, the analog input applied to SKT1
is connected directly to AIN1 of the AD7719.
LK7&8
This option selects the master clock source for the AD7719. The master clock is generated by the
on-board crystal or from an external source via SKT7. This is a double link and both links must
be moved together for the correct operation of the evaluation board.
With both links in position "A", the external clock option is selected and an external clock applied
to SKT7 is routed to the XTAL1 pin of the AD7719.
With both links in position "B", the on-board crystal is selected to provide the master clock to the
AD7719.
LK9
This link is used to select the reference source for the REFIN(-) input of the AD7719.
With this link in position "A", REFIN1(-) is connected directly to AGND.
With this link in position "B", the voltage generated across R10 (IOUT1*R10) is selected as the on-
board reference for REFIN(+). LK10 should also be connected for this set-up to connect R10 and
REFIN(-) to AGND. LK11 & LK12 should also be connected for this set-up to connect IOUT1 to
R10.
With this link in position "C", the REFIN(-) pin is connected to SKT14. An external voltage applied
to SKT14 can now be used as the REFIN(-) for the AD7719.
LK10
This link is used to select the reference source for the REFIN(+) input of the AD7719.
With this link in position "A", REFIN1(+) is connected to the output of the on-board reference
(AD780 - U6).
With this link in position "B", the REFIN1(+) pin is connected to SKT15. An external voltage
applied to SKT15 can now be used as the REFIN(+) for the AD7719.
With this link in position "C", the REFIN(+) pin is connected to AVDD.
This link should be disconnected if using the voltage generated across R10, due to IOUT1.
LK11
This link is used for selecting IOUT1*R10 as a reference voltage.
LK12
This link is used for selecting IOUT1*R10 as a reference voltage.
LK13
This link is used for selecting IOUT1*R10 as a reference voltage.
LK14
This link selects the reference source for the REFIN2 input of the AD7719.
With this link in positon "A", REFIN2 is connected to the output of the on-board reference (AD780
- U2).
With this link in position "B", the REFIN2 pin is connected to SKT16. An external voltage applied
to SKT16 can now be used as the REFIN2 for the AD7719.
SET-UP CONDITIONS
Care should be taken before applying power and signals to the evaluation board to ensure that all link positions
are as per the required operating mode. Table 1 shows the position in which all the links are set when the
evaluation board is sent out.
Table 1: Initial Link and Switch Positions
Link No. Position
LK1-LK6 IN
AD7719.
LK7&LK8 B+B
AD7719.
LK9
A
Function
Connects analog inputs from SKT1-SKT6 to the input pins AIN1-AIN6 of the
Both links in position B to select the on-board crystal as the master clock for the
This connects the REFIN1(-) input of the AD7719 to AGND.
-2-
Rev. B