Datasheet

V =
OUT
V Gain
REF
´ ´
INPUT_CODE
16384
´
OFFSETDAC_CODE
16384
V (Gain 1)- ´ -
REF
V =
OUT
V Gain
REF
´ ´
DAC_DATA_CODE
16384
´
OFFSETDAC_CODE
16384
V (Gain 1)- ´ -
REF
DAC_DATA_CODE =
INPUT_CODE (USER_GAIN+2
13
´ )
2
14
+USER_ZERO
DAC8218
www.ti.com SBAS460A –MAY 2009–REVISED DECEMBER 2009
ANALOG OUTPUTS (V
OUT
-0 to V
OUT
-7, with reference to the ground of REF-x)
When the correction engine is off (SCE = '0'):
(1)
SPACE
When the correction engine is on (SCE = '1'):
(2)
SPACE
Where:
Gain = the DAC gain defined by the GAIN bit in the Configuration Register.
INPUT_CODE = data written into the Input Data Register (SCE = '1') or DAC Data Register (SCE = '0').
OFFSETDAC_CODE = the data written into the Offset DAC Register.
USER_GAIN = the code of the Gain Register.
USER_ZERO = the code of the Zero Register.
For single-supply operation, the OFFSET-A pin must be connected to the AGND-A pin and the OFFSET-B pin
must be connected to the AGND-B pin through low-impedance connections (see the Layout section for details).
Offset DAC-A and Offset DAC-B are in a power-down state.
For dual-supply operation, the OFFSET-A and OFFSET-B default codes for a gain of 6 are 9830 with a ±3 LSB
variation, depending on the linearity of the Offset DACs. The default code for a gain of 4 is 10923 with a ±3 LSB
variation. The default codes of OFFSET-A and OFFSET-B are independently factory trimmed for both gains of 6
and 4.
The power-on default value of the Gain Register is 8192, and the default value of the Zero Register is '0'. The
DAC input registers are set to a default value of 0000h.
Note that the maximum output voltage must not be greater than (AV
DD
– 0.5V) and the minimum output voltage
must not be less than (AV
SS
+ 0.5V); otherwise, the output may be saturated.
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