mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 675

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

actual transfer function. Therefore, the quantization error will be ± 1/2 LSB in 8-bit, 10-
bit, or 12-bit modes. As a consequence, however, the code width of the first (0x000)
conversion is only 1/2 LSB and the code width of the last (0xFF or 0x3FF) is 1.5 LSB.
29.6.2.5 Linearity errors
The ADC may also exhibit non-linearity of several forms. Every effort has been made to
reduce these errors, but the system designers should be aware of them because they affect
overall accuracy. These errors are:
29.6.2.6 Code jitter, non-monotonicity, and missing codes
Analog-to-digital converters are susceptible to three special forms of error. These are
code jitter, non-monotonicity, and missing codes.
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 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.
Freescale Semiconductor, Inc.
• Zero-scale error (E
• Full-scale error (E
• Differential non-linearity (DNL): This error is defined as the worst-case difference
• Integral non-linearity (INL): This error is defined as the highest-value the (absolute
• Total unadjusted error (TUE): This error is defined as the difference between the
difference between the actual code width of the first conversion and the ideal code
width (1/2 LSB in 8-bit, 10-bit, or 12-bit modes). If the first conversion is 0x001, the
difference between the actual 0x001 code width and its ideal (1 LSB) is used.
width of the last conversion and the ideal code width (1.5 LSB in 8-bit, 10-bit, or 12-
bit modes). If the last conversion is 0x3FE, the difference between the actual 0x3FE
code width and its ideal (1 LSB) is used.
between the actual code width and the ideal code width for all conversions.
value of the) running sum of 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.
actual transfer function and the ideal straight-line transfer function and includes all
forms of error.
FS
ZS
): This error is defined as the difference between the actual code
MCF51JF128 Reference Manual, Rev. 2, 03/2011
) (sometimes called offset): This error is defined as the
Preliminary
Chapter 29 Analog-to-Digital Converter (ADC)
675