Method for calculating compliance voltage based on which MAX5113 DAC channel(s) is used and the customer's maximum setting
- FS = full scale of selected DAC channel. For example: 10mA, 90mA, 180mA, 360mA
- MS = maximum setting. This is the maximum current that the customer will use. Example: 100mA maximum.
Compliance voltage = VCC – (0.6V*MS/FS + 0.2V*(MS/FS)^0.5)
Example 1:
- FS = 300mA output channel
- MS = 150mA maximum output used by customer
Compliance voltage =VCC –( 0.6V *150mA/300mA + 0.2V*(150mA/300mA)^0.5)= 0.3V + 0.14V= 0.44V => VCC – 0.44V.
Example 2:
- FS = 20mA and 90mA channels connected together = 110mA
- MS = 100mA
Compliance voltage = VCC –( 0.6V *100mA/110mA + 0.2V*(100mA/110mA)^0.5) => VCC – 0.736V.
The formula is for room temperature, aging inclusive.
The 0.6V coefficient has minimal temperature coefficient, <5% change across temperature.
The 0.2V coefficient will change with temperature, but we do not have characterization data on this to provide a good estimated value.