LTC1655LIN8 datasheet(10/16 Pages) LINER

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LTC1655/LTC1655L

APPLICATIONS INFORMATION

Rail-to-Rail Output Considerations

In any rail-to-rail DAC, the output swing is limited to

voltages within the supply range.

If the DAC offset is negative, the output for the lowest

codes limits at 0V as shown in Figure 1b.

Similarly, limiting can occur near full-scale when the REF

pin is tied to VCC/2. If VREF = VCC/2 and the DAC full-scale

error (FSE) is positive, the output for the highest codes

limits at VCC as shown in Figure 1c. No full-scale limiting

can occur if VREF is less than (VCC – FSE)/2.

Offset and linearity are defined and tested over the region

of the DAC transfer function where no output limiting can

occur.

Figure 1. Effects of Rail-to-Rail Operation On a DAC Transfer Curve. (a) Overall Transfer Function (b) Effect of Negative

Offset for Codes Near Zero Scale (c) Effect of Positive Full-Scale Error for Input Codes Near Full Scale When VREF = VCC/2

1655/55L F01

INPUT CODE

OUTPUT

VOLTAGE

NEGATIVE

OFFSET

32768

65535

INPUT CODE

OUTPUT

VOLTAGE

VREF = VCC/2

VCC

VREF = VCC /2

INPUT CODE

OUTPUT

VOLTAGE

POSITIVE

FSE

(1b)

(1a)

(1c)

LTC1655LIN8 데이터시트(PDF) 10 Page - Linear Technology