7477 datasheet(220/361 Pages) RENESAS

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7470/7471/7477/7478 GROUP USER’S MANUAL

HARDWARE

1.21 Electrical characteristics

1-213

1.21.5 A-D conversion standard characteristic

(1) Relative precision (7470/7471 group)

Figure 1.21.17 to Figure 1.21.18 show the A-D conversion standard characteristics on the relative

precision of the 7470/7471 group.

In the graph, the lower line indicates a deviation from the ideal value at the point where the output

code changes, namely, relative precision error (ERROR). For example, in Figure 1.21.17, the change

of “3F16 to 4016” of the output code occurs ideally at the point of IN0 = 757.32 mV. However, since

the relative precision error is -3.567 mV, “757.32 - 3.567 = 753.753 mV” represents a measuring

change point.

In the graph, the upper line indicates an input voltage width (1 LSB WIDTH) in which the output code

is the same. For example, in Figure 1.21.17, since the measured value of input voltage width, when

the output code is “3F16”, is 10.701 mV, the differential nonlinear error on the relative precision

Fig. 1.21.17 A-D conversion standard characteristics, relative precision error (1)

represents “10.701 -11.89 = -1.189 mV (-0.1 LSB)”.

7477 Datasheet(PDF) 220 Page - Renesas Technology Corp