The voltage output of the DAC53204 is turned into
a current through the series resistor R3. R3 is calculated
by:
Avoid DAC codes near zero- and full-scale when
determining the DAC output voltage range to avoid the zero- and full-scale
errors at these codes. This design uses the internal 1.21 V reference with a
gain of ×1.5 giving a full-scale voltage of 1.82 V. The DAC53204 has a max
zero-code error of 15mV, so a 20-mV minimum output is a safe choice. The maximum
output becomes:
With this DAC range, R3 becomes:
The DAC codes for
VDAC,MAX and VDAC,MIN are stored in the
DAC-MARGIN-HIGH and DAC-MARGIN-LOW registers. The codes programmed to these
registers, in decimal, is calculated using:
The equations become:
This is rounded to 677d and 11d to give a VDAC,MAX of 1.2 V and
a VDAC,MIN of 19.5mV.