MC9RS08KA8RM Datasheet, PDF (117/190 Pages) Freescale Semiconductor, Inc – MC9RS08KA8 Features

Analog-to-Digital Converter (RS08ADC10V1)
• Differential non-linearity (DNL) — The worst-case difference between the actual code width and
the ideal code width for all conversions.
• Integral non-linearity (INL) — The highest-value (the absolute value) of the running sum DNL
achieves. More simply, this is the worst-case difference of the actual transition voltage to a given
code and its corresponding ideal transition voltage, for all codes.
• Total unadjusted error (TUE) — The difference between the actual transfer function and the ideal
straight-line transfer function, and therefore includes all forms of error.
10.6.2.6 Code Jitter, Non-Monotonicity and Missing Codes
Analog-to-digital converters are susceptible to three special forms of error;
Code jitter— is when, at certain points, a given input voltage converts to one of two values when sampled
repeatedly. Ideally, when the input voltage is infinitesimally smaller than the
transition voltage, the converter yields the lower code (and vice-versa). However,
even very small amounts of system noise can cause the converter to be
indeterminate (between two codes) for a range of input voltages around the
transition voltage. This range is normally around ±1/2 LSB and increases with
noise. Repeatedly sampling the input and averaging the result. Additionally the
techniques discussed in Section 10.6.2.3 reduce this error.
Non-monotonicity —is defined as when, except for code jitter, the converter converts to a lower code for
a higher input voltage.
Missing codes —are values never converted for any input value.
In 8-bit or 10-bit mode, the ADC is monotonic and has no missing codes.
MC9RS08KA8 Series Reference Manual, Rev. 3
Freescale Semiconductor
117