LTC1448CS8 datasheet(7/12 Pages) LINER

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LTC1448

APPLICATIONS INFORMATION

1448 F01

INPUT CODE

(b)

OUTPUT

VOLTAGE

NEGATIVE

OFFSET

2048

4095

INPUT CODE

OUTPUT

VOLTAGE

(a)

VREF = VCC

(c)

INPUT CODE

OUTPUT

VOLTAGE

POSITIVE

FSE

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. If VREF = VCC 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.

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

LTC1448CS8 Datasheet(PDF) 7 Page - Linear Technology