
LTC2755
16
2755f
System Offset Adjustment
Many systems require compensation for overall system
offset. The RVOSX offset adjustment pins are provided for
this purpose. For noise immunity and ease of adjustment,
the control voltage is attenuated to the DAC output:
VOS = –0.01 V(RVOSX) [0V to 5V, ±2.5V spans]
VOS = –0.02 V(RVOSX) [0V to 10V, ±5V, –2.5V to 7.5V
spans]
VOS = –0.04 V(RVOSX) [±10V span]
The nominal input range of this pin is ±5V; other reference
voltages of up to ±15V may be used if needed. The RVOSX
pins have an input impedance of 1MΩ. To preserve the
settling performance of the LTC2755, drive this pin with a
Thevenin-equivalent impedance of 10k or less. Short any
unused RVOSX system offset adjustment pins to GND.
Table 2. Span Codes
S2
S1
S0
SPAN
0
Unipolar 0V to 5V
0
1
Unipolar 0V to 10V
0
1
0
Bipolar –5V to 5V
0
1
Bipolar –10V to 10V
1
0
Bipolar –2.5V to 2.5V
1
0
1
Bipolar –2.5V to 7.5V
Codes not shown are reserved and should not be used.
Table 3. Address Codes
A2
A1
A0
DAC CHANNEL
0
DAC A
0
1
DAC B
0
1
0
DAC C
0
1
DAC D
1
ALL DACs*
Codes not shown are reserved and should not be used.
*If readback is taken using the ALL DACs address, the LTC2755 defaults
to DAC A.
OPERATION