MAX5122 Maxim, MAX5122 Datasheet - Page 15

• Manufacturer Part Number: MAX5122
• Description: +5V/+3V / 12-Bit / Serial / Force/Sense DACs with 10ppm/C Internal Reference
• Manufacturer: Maxim

Integral nonlinearity (Figure 8a) is the deviation of the
values on an actual transfer function from a straight
line. This straight line can be either a best-straight-line
fit (closest approximation to the actual transfer curve)
or a line drawn between the endpoints of the transfer
function, once offset and gain errors have been nulli-
fied. For a DAC, the deviations are measured at every
single step.
Differential nonlinearity (Figure 8b) is the difference
between an actual step height and the ideal value of
Figure 8a. Integral Nonlinearity
Figure 8b. Differential Nonlinearity
__________Applications Information
7
6
5
4
3
2
1
0
6
5
4
3
2
1
0
000
000
+5V/+3V, 12-Bit, Serial, Force/Sense DACs
001
001
______________________________________________________________________________________
010
DIGITAL INPUT CODE
DIGITAL INPUT CODE
AT STEP
001 (1/4 LSB )
010
Differential Nonlinearity (DNL)
011
1 LSB
011
Integral Nonlinearity (INL)
100
DIFFERENTIAL
LINEARITY ERROR (+1/4 LSB)
AT STEP
O11 (1/2 LSB )
DIFFERENTIAL LINEARITY
ERROR (-1/4 LSB)
100
101
with 10ppm/°C Internal Reference
110
101
1 LSB
Definitions
111
1LSB. If the magnitude of the DNL is less than or equal
to 1LSB, the DAC guarantees no missing codes and is
monotonic.
The offset error (Figure 8c) is the difference between
the ideal and the actual offset point. For a DAC, the off-
set point is the step value when the digital input is zero.
This error affects all codes by the same amount and
can usually be compensated for by trimming.
Gain error (Figure 8d) is the difference between the
ideal and the actual full-scale output voltage on the
transfer curve, after nullifying the offset error. This error
alters the slope of the transfer function and corre-
sponds to the same percentage error in each step.
Figure 8c. Offset Error
Figure 8d. Gain Error
OFFSET POINT
ACTUAL
3
2
1
0
7
6
5
4
0
000
000
IDEAL DIAGRAM
100
IDEAL OFFSET
POINT
GAIN ERROR
DIAGRAM
(-1 1/4 LSB)
ACTUAL
001
IDEAL FULL-SCALE OUTPUT
DIGITAL INPUT CODE
DIGITAL INPUT CODE
101
OFFSET ERROR
(+1 1/4 LSB)
010
110
IDEAL DIAGRAM
FULL-SCALE
OUTPUT
ACTUAL
011
111
Offset Error
Gain Error
15