DAC7562T Datasheet, PDF (33/60 Pages) Texas Instruments – Internal Reference

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DAC7562T, DAC7563T, DAC8162T
DAC8163T, DAC8562T, DAC8563T
SLASE61A – SEPTEMBER 2015 – REVISED OCTOBER 2015
8.4.2 Gain Function
The gain register controls the GAIN setting in the DAC transfer function:
V_{O UT}
=
æ
ç
è
D_IN
2ⁿ
ö
÷
ø
´
V_REF
´ Gain
(2)
The DAC756xT, DAC816xT, and DAC856xT devices have a gain register for each channel. The gain for each
channel, in Equation 2, is either 1 or 2. This gain is automatically set to 2 when using the internal reference, and
is automatically set to 1 when the internal reference is disabled (default). However, each channel can have either
gain by setting the registers appropriately. The gain registers are accessible by setting the serial interface
command bits to 000, address bits to 010, and using DB1 for DAC-B and DB0 for DAC-A. See Table 7 and
Table 17 for the full command structure. The gain registers are automatically reset to provide either gain of 1 or 2
when the internal reference is powered off or on, respectively. After the reference is powered off or on, the gain
register is again accessible to change the gain.
DB1, DB0
DB0
DB1
Table 7. DAC-n Selection for Gain Register Command
Value
0
1
0
1
Gain
DAC-A uses gain = 2 (default with internal reference)
DAC-A uses gain = 1 (default with external reference)
DAC-B uses gain = 2 (default with internal reference)
DAC-B uses gain = 1 (default with external reference)
8.4.3 Software Reset Function
The DAC756xT, DAC816xT, and DAC856xT devices contain a software reset feature. The software reset
function is accessed by setting the serial interface command bits to 101. The software reset command contains
two reset modes which are software-programmable by setting bit DB0 in the shift register. Table 8 and Table 17
show the available software reset commands.
Table 8. Software Reset
DB0
0
1
Registers Reset to Default Values
DAC registers
Input registers
DAC registers
Input registers
LDAC registers
Power-down registers
Internal reference register
Gain registers
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