11

LTC1654

1654fb

Rail-to-Rail Output Considerations

Rail-to-rail DACs take full advantage of the supply range

available to them, but cannot produce output voltages

If REFLO is tied to GND, the output for the lowest codes

may limit at 0V, as shown in Figure 2b. Similarly, limiting

shown in Figure 2c.

The offset, gain error and linearity of the LTC1654 are

defined and tested in output ranges that avoid limiting.

the code which gives a nominal output of 32mV above

ground; see Table 2.

Figure 2. Effects of Rail-to-Rail Operation On a DAC Transfer Curve: (a) Overall Transfer Function, (b) Effect of Negative

1654 F02

INPUT CODE

(b)

OUTPUT

VOLTAGE

NEGATIVE

OFFSET

0V

8192

0

16383

INPUT CODE

OUTPUT

VOLTAGE

(a)

(c)

INPUT CODE

OUTPUT

VOLTAGE

POSITIVE

FSE

APPLICATIO S I FOR ATIO

4.096 2.048

1

128

256

1/2

256

512