MCP40D17 Microchip Technology Inc., MCP40D17 Datasheet - Page 42

• Manufacturer Part Number: MCP40D17
• Description: 7-bit Single I 2 C? With Command Code Digital Pot With Volatile Memory In Sc70
• Manufacturer: Microchip Technology Inc.

MCP40D17/18/19
Step resistance (R
setting to the next. This value will be dependent on the
R
the calculation for the step resistance while
shows the typical step resistances for each device.
EQUATION 6-1:
Equation 6-2
determine the resistance between the wiper and
terminal B.
EQUATION 6-2:
The digital potentiometer is available in four nominal
resistances (R
defined as the resistance between terminal A and
terminal B. The four nominal resistances are 5 kΩ,
10 kΩ, 50 kΩ, and 100 kΩ.
The total resistance of the device has minimal variation
due to operating voltage (see
Figure
TABLE 6-2:
DS22152B-page 42
MCP40D17/18/19-
502
MCP40D17/18/19-
103
MCP40D17/18/19-
503
MCP40D17/18/19-
104
AB
Part Number
value that has been selected.
2-47, or
illustrates the calculation used to
AB
Figure
N = 0 to 127 (decimal)
R
) where the nominal resistance is
STEP RESISTANCES
R
WB
S
S
) is the resistance from one tap
Case
Minimum
Typical
Maximum
Minimum
Typical
Maximum
Minimum
Typical
Maximum
Minimum
Typical
Maximum
=
2-65).
R
R
=
S
WB
R
---------
127
R
------------- -
AB
CALCULATION
127
AB
CALCULATION
N
Resistance (Ω)
Figure
+
R
4000
5000
6000
8000
10000
12000
40000
50000
60000
80000
100000
120000
Equation 6-1
(R
W
Total
2-11,
AB
)
Figure
Step (R
314.961
393.701
472.441
629.921
787.402
944.882
Table 6-2
31.496
39.370
47.244
62.992
78.740
94.488
shows
2-29,
S
)
A POR/BOR event will load the Volatile Wiper register
value with the default value.
default values offered.
TABLE 6-3:
Resistance
-502
-103
-503
-104
Note 1:
Code
Custom POR/BOR Wiper Setting options
are available, contact the local Microchip
Sales Office for additional information.
Custom options have minimum volume
requirements.
R
100.0 kΩ
10.0 kΩ
50.0 kΩ
Typical
AB
5.0 kΩ
DEFAULT FACTORY
SETTINGS SELECTION
Value
© 2009 Microchip Technology Inc.
Mid-scale
Mid-scale
Mid-scale
Mid-scale
Default POR Wiper
Setting
Table 6-3
shows the
Code
3Fh
3Fh
3Fh
3Fh
(1)