ADM9240
The input ranges of the analog inputs are shown in more detail
in Table I.
The +V
CCP1
and +V
CCP2
inputs are used to measure processor
core voltages, and have an input range from 0 V to 3.6 V. If
only a single processor core voltage is being monitored, the
V
CCP2
input may be used to monitor the –12 V supply. This is
achieved by using a resistive divider network referenced to a
known positive dc voltage. This is illustrated in Figure 4.
INPUT CIRCUITS
42.7k
+V
CCP2
97.3k
122.2k
+12V
22.7k
91.6k
+5V
55.2k
61.1k
+3.3V
80.9k
36.7k
+2.5V
111.2k
42.7k
97.3k
50pF
25pF
25pF
25pF
MUX
35pF
50pF
The internal structure for the analog inputs is shown in Figure
3. Each input circuit consists of an input protection diode, an
attenuator, plus a capacitor to form a first order low-pass filter
which gives the input immunity to high frequency noise.
+V
CCP1
Figure 3. Internal Structure of Analog Inputs
Table I. A/D Output Code vs. V
IN
+12 V
IN
<0.062
0.062–0.125
0.125–0.187
0.188–0.250
0.250–0.313
0.313–0.375
0.375–0.438
0.438–0.500
0.500–0.563
+5 V
IN
<0.026
0.026–0.052
0.052–0.078
0.078–0.104
0.104–0.130
0.130–0.156
0.156–0.182
0.182–0.208
0.208–0.234
Input Voltage
+3.3 V
IN
+2.5 V
IN
<0.0172
0.017–0.034
0.034–0.052
0.052–0.069
0.069–0.086
0.086–0.103
0.103–0.120
0.120–0.138
0.138–0.155
<0.013
0.013–0.026
0.026–0.039
0.039–0.052
0.052–0.065
0.065–0.078
0.078–0.091
0.091–0.104
0.104–0.117
l
l
l
0.833–0.846
l
l
l
1.667–1.680
l
l
l
2.500–2.513
l
l
l
3.190–3.203
3.203–3.216
3.216–3.229
3.229–3.242
3.242–3.255
3.255–3.268
3.268–3.281
3.281–3.294
3.294–3.307
3.307–3.320
>3.320
–9–
+V
CCP1
<0.014
0.014–0.028
0.028–0.042
0.042–0.056
0.056–0.070
0.070–0.084
0.084–0.098
0.098–0.112
0.112–0.126
+V
CCP2
<0.014
0.014–0.028
0.028–0.042
0.042–0.056
0.056–0.070
0.070–0.084
0.084–0.098
0.098–0.112
0.112–0.126
A/D Output
Decimal
Binary
0
1
2
3
4
5
6
7
8
00000000
00000001
00000010
00000011
00000100
00000101
00000110
00000111
00001000
4.000–4.063
1.666–1.692
1.100–1.117
0.900–0.914
0.900–0.914
64 (1/4 Scale)
01000000
8.000–8.063
3.330–3.560
2.200–2.217
1.800–1.814
1.800–1.814
128 (1/2 Scale) 10000000
12.000–12.063
5.000–5.026
3.300–3.317
2.700–2.714
2.700–2.714
192 (3/4 Scale) 11000000
15.313–15.375
15.375–15.438
15.438–15.500
15.500–15.563
15.563–15.625
15.625–15.688
15.688–15.750
15.750–15.813
15.813–15.875
15.875–15.938
>15.938
REV. 0
6.380–6.406
6.406–6.432
6.432–6.458
6.458–6.484
6.484–6.510
6.510–6.536
6.536–6.562
6.562–6.588
6.588–6.615
6.615–6.640
>6.640
4.210–4.230
4.230–4.245
4.245–4.263
4.263–4.280
4.280–4.300
4.300–4.314
4.314–4.331
4.331–4.348
4.348–4.366
4.366–4.383
>4.383
3.445–3.459
3.459–3.473
3.473–3.487
3.487–3.501
3.501–3.515
3.515–3.529
3.529–3.543
3.543–3.558
3.558–3.572
3.572–3.586
>3.586
3.445–3.459
3.459–3.473
3.473–3.487
3.487–3.501
3.501–3.515
3.515–3.529
3.529–3.543
3.543–3.558
3.558–3.572
3.572–3.586
>3.586
245
246
247
248
249
250
251
252
253
254
255
11110101
11110110
11110111
11111000
11111001
11111010
11111011
11111100
11111101
11111110
11111111
AD [ ANALOG DEVICES ]
