Texas Instruments ADS1224EVM, Руководство пользователя

Страница: 22 / 34

Jumpers
2-8
2.2.2 J4 Pins 5−10: Digital Power Supply Select
One of pin pairs 5−6, 7−8 or 9−10 must be shorted to select the digital supply
level on for the ADS1224. This selection determines the level at which the
ADS1224 digital lines will operate, so it is very important to set this correctly.
It is possible to measure the overall digital current of the board using these
jumpers.
Connect only one of pin pairs 5−6, 7−8 or 9−10.
Shorting more than one of these jumpers can potentially damage
your motherboard, or even damage the ADS1224EVM itself.
The ADS1224 inputs are not 5V tolerant, nor are they TTL-compatible.
Although protection resistance is included in each digital line, it may be neces-
sary to provide level translation if the ADS1224 digital supply must be powered
from a different voltage than the external logic.
Note that the digital and analog supplies for the ADS1224 are independent,
so level translation should rarely be needed.
2.2.3 J4 Pins 11−12: Analog-Digital Ground Shorting Jumper
Shorting this jumper connects AGND from J3 to DGND.