Intel 8XC196MH, 8XC196MD, 8XC196MC manual Ideal A/D Conversion Characteristic

ANALOG-TO-DIGITAL (A/D) CONVERTER

Ø OUTPUT CODE, Q

7

6

5

4

3

2

1

0

FINAL CODE TRANSITION OCCURS

WHEN THE APPLIED VOLTAGE IS

EQUAL TO (Vref – 1.5 (LSB)).

ACTUAL CHARACTERISTIC OF

AN IDEAL A/D CONVERTER

THE VOLTAGE CHANGE

BETWEEN THE ADJACENT CODE

TRANSITIONS (THE “CODE

WIDTH”) IS = 1 LSB.

		FIRST CODE TRANSITION OCCURS
		WHEN THE APPLIED VOLTAGE IS
		EQUAL TO 1/2 LSB.
1/2	1	2	3	4	5	6	6 1/2	7	8
			INPUT VOLTAGE (LSBs)

A0083-01

Figure 12-9. Ideal A/D Conversion Characteristic

Note that the ideal characteristic possesses unique qualities:

•its first code transition occurs when the input voltage is 0.5 LSB;

•its full-scale code transition occurs when the input voltage equals the full-scale reference voltage minus 1.5 LSB (VREF – 1.5LSB); and

•its code widths are all exactly one LSB.

These qualities result in a digitization without zero-offset, full-scale, or linearity errors; in other words, a perfect conversion.

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