56F8335 datasheet(148/160 Pages) FREESCALE

148 / 160 page

56F8335 Technical Data, Rev. 5

148

Freescale Semiconductor

Preliminary

Figure 10-21 ADC Absolute Error Over Processing and Temperature Extremes Before

and After Calibration for VDCin = 0.60V and 2.70V

Note: The absolute error data shown in the graphs above reflects the effects of both gain error and offset

error. The data was taken on 15 parts: three each from four processing corner lots as well as three from one

nominally processed lot, each at three temperatures: -40°C, 27°C, and 150°C (giving the 45 data points

shown above), for two input DC voltages: 0.60V and 2.70V. The data indicates that for the given

population of parts, calibration significantly reduced (by as much as 39%) the collective variation (spread)

of the absolute error of the population. It also significantly reduced (by as much as 80%) the mean

(average) of the absolute error and thereby brought it significantly closer to the ideal value of zero.

Although not guaranteed, it is believed that calibration will produce results similar to those shown above

for any population of parts including those which represent processing and temperature extremes.

10.16 Equivalent Circuit for ADC Inputs

Figure 10-22 illustrates the ADC input circuit during sample and hold. S1 and S2 are always open/closed

56F8335 Datasheet(PDF) 148 Page - Freescale Semiconductor, Inc