DAC8718 Datasheet, PDF (36/60 Pages) Texas Instruments – Octal, 16-Bit, Low-Power, High-Voltage Output, Serial Input DIGITAL-TO-ANALOG CONVERTER

DAC8718
SBAS467A – MAY 2009 – REVISED DECEMBER 2009
www.ti.com
USER-CALIBRATION FOR ZERO-CODE ERROR AND GAIN ERROR
The DAC8718 implements a digital user-calibration function that allows for trimming gain and zero errors on the
entire signal chain. This function can eliminate the need for external adjustment circuits. Each DAC channel has
a Zero Register and Gain Register. Using the correction engine, the data from the Input Data Register are
operated on by a digital adder and multiplier controlled by the contents of the Zero and Gain registers,
respectively. The calibrated DAC data are then stored in the DAC Data Register where they are finally
transferred into the DAC latch and set the DAC output. Each time the data are written to the Input Data Register
(or to the Gain or Zero registers), the data in the Input Data Register are corrected, and the results automatically
transferred to the DAC Data Register.
The range of the gain adjustment coefficient is 0.5 to 1.5. The range of the zero adjustment is –32768 LSB to
+32767 LSB, or ±50% of full scale.
There is only one correction engine in the DAC8718, which is shared among all channels.
If the user-calibration function is not needed, the correction engine can be turned off. Setting the SCE bit in the
Configuration Register to '0' turns off the correction engine. Setting SCE to '1' enables the correction engine.
When SCE = '0', the data are directly transferred to the DAC Data Register. In this case, writing to the Gain
Register or Zero Register updates the Gain and Zero registers but does not start a math engine calculation.
Reading these registers returns the written values.
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