User`s manual

ManualsBrandsMC ManualsComputer equipmentPCI-DAS1602

4.2 ANALOG OUTPUT CALIBRATION

The analog output circuits are calibrated for both gain and offset. Coarse and Fine offset adjustments are

made in the output buffer section. The tuning range of these adjustments allows for maximum DAC and

output buffer offsets. Coarse and Fine gain calibration is performed via adjustments to the DAC

reference.

Note that there are no references associated with the DAC calibration - a fully calibrated ADC set to the

respective DAC range is used as the measurement system. Sub-ranging of the ADC is used to ensure

highly accurate offset adjustments.

The calibration scheme for the Analog Out section is shown in Figure 4-2 below. This circuit is

duplicated for both DAC0 and DAC1.

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Analog-Out

DAC

Ref

Trim Dac

(Coarse)

Trim Dac

(Fine)

Gain Adj

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Gain Adj

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Gain Adj

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Trim Dac

(Coarse)

Trim Dac

(Fine)

Offset Adj

Analog Out

Figure 4-2. Analog Output Calibration Scheme