MCP23018/MCP23S18
FIGURE 1-3:
VOLTAGE AND CODE EXAMPLE
Assume:
n = A2, A1, A0 in opcode
ratio = R2/(R1+R2)
V2 = voltage on ADDR pin
V2(min) = V2 - (VDD/8) x %tolerance
V2(max) = V2 + (VDD/8) x %tolerance
VDD= 1.8
R2=2n+1 R1=16-R2 R2/(R1+R2)
10% Tolerance (total)
V2(min) V2(max)
0.00 0.14
n
n
n
n
V2
0.113
0
1
2
3
4
5
6
7
1
3
5
7
9
11
13
15
15
13
11
9
7
5
0.0625
0.1875
0.3125
0.4375
0.5625
0.6875
0.8125
0.9375
0.32
0.54
0.77
0.99
1.22
1.44
1.67
0.36
0.59
0.81
1.04
1.26
1.49
1.80
0.338
0.563
0.788
1.013
1.238
1.463
1.688
3
1
VDD= 2.7
R2=2n+1 R1=16-R2 R2/(R1+R2)
10% Tolerance (total)
V2(min) V2(max)
0.00 0.19
V2
0.169
0.506
0.844
1.181
1.519
1.856
2.194
2.531
0
1
2
3
4
5
6
7
1
3
5
7
9
11
13
15
15
13
11
9
7
5
0.0625
0.1875
0.3125
0.4375
0.5625
0.6875
0.8125
0.9375
0.48
0.82
1.16
1.50
1.83
2.17
2.51
0.53
0.87
1.20
1.54
1.88
2.22
2.70
3
1
VDD= 3.3
10% Tolerance (total)
V2(min) V2(max)
0.00 0.23
R2=2n+1
R1=16-R2 R2/(R1+R2)
V2
0
1
2
3
4
5
6
7
1
3
5
7
9
11
13
15
15
13
11
9
7
5
0.0625
0.1875
0.3125
0.4375
0.5625
0.6875
0.8125
0.9375
0.206
0.619
1.031
1.444
1.856
2.269
2.681
3.094
0.60
1.01
1.42
1.83
2.25
2.66
3.07
0.64
1.05
1.47
1.88
2.29
2.70
3.30
3
1
VDD= 5.5
R2=2n+1 R1=16-R2 R2/(R1+R2)
10% Tolerance (total)
V2(min) V2(max)
0.00 0.37
V2
0
1
2
3
4
5
6
7
1
3
5
7
9
11
13
15
15
13
11
9
7
5
0.0625
0.1875
0.3125
0.4375
0.5625
0.6875
0.8125
0.9375
0.344
1.031
1.719
2.406
3.094
3.781
4.469
5.156
1.01
1.70
2.38
3.07
3.76
4.45
5.13
1.05
1.74
2.43
3.12
3.80
4.49
5.50
3
1
© 2008 Microchip Technology Inc.
DS22103A-page 11
MICROCHIP [ MICROCHIP ]
