Datasheet MCP47FXBX4/8 (Microchip) - 118

MCP47FXBX4/8
C.11 Integral Nonlinearity (INL) The Integral Nonlinearity (INL) error is the maximum
deviation of an actual transfer function from an ideal
transfer function (straight line) passing through the
defined end points of the DAC transfer function (after
Offset and Gain errors have been removed).
For the MCP47FXBX4/8, INL is calculated using the
defined end points, DAC code 100 and code 4000. INL
can be expressed as a percentage of FSR or in LSb.
INL is also called Relative Accuracy. Equation C-6
shows how to calculate the INL error in LSb and
Figure C-4 shows an example of INL accuracy.
Positive INL means VOUT voltage higher than the ideal
one. Negative INL means VOUT voltage lower than the
ideal one. EQUATION C-6: INL ERROR  VOUT – VCalc_Ideal 
EINL = ---------------V LSb(Measured)
Where:
INL is expressed in LSb.
VCalc_Ideal = Code × VLSb(Measured) + VOS
VOUT(Code = n) = The measured DAC output
voltage with a given DAC
register code
VLSb(Measured) = For Measured:
(VOUT(4000) – VOUT(100)/3900
VOS = Measured offset voltage C.12 Differential Nonlinearity (DNL) The Differential Nonlinearity (DNL) error (see
Figure C-5) is the measure of step-size between codes
in an actual transfer function. The ideal step-size
between codes is 1 LSb. A DNL error of zero would
imply that every code is exactly 1 LSb wide. If the DNL
error is less than 1 LSb, the DAC guarantees monotonic
output and no missing codes. Equation C-7 shows how
to calculate the DNL error between any two adjacent
codes in LSb. EQUATION C-7:  V OUT(code = n+1) – V OUT(code = n) 
EDNL = -------------------------– 1
VLSb(Measured)
Where:
DNL is expressed in LSb.
VOUT(code = n) = The measured DAC output
voltage with a given DAC
register code.
VLSb(Measured) = For Measured:
(VOUT(4000) – VOUT(100)/3900 7 DNL = 0.5 LSb 6
5
DNL = 2 LSb Analog 4
Output
(LSb) 3
7 INL = < -1 LSb DNL ERROR 2 6
INL = -1 LSb 5
Analog 4
Output
(LSb) 3 1
0
000 001 010 011 100 101 110 111 DAC Input Code INL = 0.5 LSb Ideal Transfer Function 2 Actual Transfer Function 1 FIGURE C-5: DNL ACCURACY. 0
000 001 010 011 100 101 110 111
DAC Input Code Ideal Transfer Function
Actual Transfer Function FIGURE C-4: DS20006368A-page 118 INL ACCURACY.  2020 Microchip Technology Inc.