DAC712
www.ti.com ................................................................................................................................................. SBAS023A–SEPTEMBER 2000–REVISED JULY 2009
LOAD CONNECTIONS
In some applications it is impractical to return the load
to the ACOM pin of the D/A converter. Sensing the
output voltage at the SYSTEM GROUND point is
reasonable, because there is no change in the
DAC712 ACOM current, provided that R3 is a
low-resistance ground plane or conductor. In this
case, DCOM may be connected to SYSTEM
GROUND as well.
Because the reference point for VOUT and VREF OUT is
the ACOM pin, it is important to connect the D/A
converter load directly to the ACOM pin; see
Figure 12.
Lead and contact resistances are represented by R1
through R3. As long as the load resistance RL is
constant, R1 simply introduces a gain error and can
be removed by gain adjustment of the D/A converter
or system-wide gain calibration. R2 is part of RL if the
output voltage is sensed at ACOM.
DAC712
10kW
10kW
VREF
R1
VOUT
Bus
Interface
Sense
Output
RL
DCOM
ACOM
R2
Alternate Ground
Sense Connection
R3
To +VCC
0.01mF(1)
0.01mF
Analog
Power
Supply
System Ground
To -VCC
(1) Locate close to the DAC712 package.
Figure 12. System Ground Considerations for High-Resolution D/A Converters
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