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19.2 D/A CONVERTER CONFIGURATION
The D/A converter used in the A/D converter of the PD17062 is a resistor string D/A converter consisting
of 16 resistors connected in series between the V
point is selected. The configuration of the D/A converter is shown in Fig. 19-2.
0
ADCR
4
With the configuration shown above, the D/A converter outputs a ground level when the ADCR is set with
value 0000B. It also outputs 1/32 V
the reference voltage V
REF
2n – 1
V
= V
REF
DD
32
234
and GND pins in which a voltage at each resistor connection
DD
Fig. 19-2 D/A Converter Configuration
1/2R
R
R
1
2
Selector
when the ADCR is set with 0001B. The following expression represents
DD
that the D/A converter outputs when the ADCR is set with value n (decimal).
(where 15
n
1)
Table 19-1 D/A Converter Reference Voltage
Set data (ADCR)
Hexadecimal
Binary
0
0000
1
0001
2
0010
3
0011
4
0100
5
0101
6
0110
7
0111
8
1000
9
1001
A
1010
B
1011
C
1100
D
1101
E
1110
F
1111
R
R
R
3/2R
13
14
15
Reference voltage (V
)
REF
V
V
= 5 V
DD
DD
0
0 [V]
1/32
0.15625
3/32
0.46875
5/32
0.78125
7/32
1.09375
9/32
1.40625
11/32
1.71875
13/32
2.03125
15/32
2.34375
17/32
2.65625
19/32
2.96875
21/32
3.28125
23/32
3.59375
25/32
3.90625
27/32
4.21875
29/32
4.53125
PD17062
V
DD
D/A output
(reference voltage)
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