User`s guide

Elan Digital Systems Ltd. 9 AD125 USER’S GUIDE
inside the AD125 at a “star-point”. All digital front-end circuits
use a separate ground trace to the front-end analogue circuits to
reduce such switching noise problems on the card itself. The
AGND/GND link occurs at the PCMCIA 68-way connector.
6. If using the inputs in differential mode, do not forget to keep the
common mode signal within the common mode range of the
AD125s inputs. The “best” you can achieve is to ensure that the -
side is very close to the card’s AGND level. This will give you
the maximum amount of “headroom” for the + signal. You can
arrange this (without making a direct connection) using an
external resistor of say 10K to “pull” the - side close to AGND.
2.4 D to A Converters
The two D to A converters on the MF series of cards can be set
individually to output a 12-bit resolution voltage. Each DAC drives
off card through a 10O series resistor and has a nominal range of 0 to
2.5V. Additionally, the output of each DAC is amplified and offset
so that a secondary nominal range of -10V to +10V is available.
These two amplifiers also drive off card through 10O series resistors.
This means that there is a total of four output pins for the two DACs.