CAT5132GZ-100TE13 CATALYST [Catalyst Semiconductor], CAT5132GZ-100TE13 Datasheet - Page 11

• Manufacturer Part Number: CAT5132GZ-100TE13
• Description: 15 Volt Digitally Programmable Potentiometer (DPP) with 128 Taps and 2-wire Interface
• Manufacturer: CATALYST [Catalyst Semiconductor]

© 2005 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
POTENTIOMETER OPERATION
Power-On
The CAT5132 is a 128-position, digital controlled
potentiometer. At power-up the device turns on at the
mid-point wiper location (64) until the wiper register can
be loaded with the nonvolatile memory location previously
stored in the device. After the nonvolatile memory data
is loaded into the wiper register the wiper location will
change to the previously stored wiper position.
The end-to-end nominal resistance of the potentiometer
has 128 contact points linearly distributed across the
total resistor. Each of these contact points is addressed
by the 7 bit wiper register which is decoded to select one
of these 128 contact points.
Each contact point generates a linear resistive value
between the 0 position and the 127 position. These
values can be determined by dividing the end-to-end
value of the potentiometer by 127. In the case of the
10k
each wiper position. However in addition to the ~79 for
each resistive segment of the potentiometer, a wiper
resistance offset must be considered. Table 8 shows the
effect of this value and how it would appear on the wiper
terminal.
potentiometer~79
is the resistance between
11
This offset will appear in each of the CAT5132 end-to-
end resistance values in the same way as the 10k
example. However resistance between each wiper
position for the 50k version will be ~395 and for the
100k version will be ~790 .
Table 8. Potentiometer Resistance and Wiper
Resistance Offset Effects
P
P
o
o
1
1
1
s
s
0
6
0
6
0
2
2
2
t i
t i
0
3
0
4
1
7
6
7
o i
o i
n
n
T
T
y
y
1
1
p
p
5
0
0
5
c i
c i
0 ,
0 ,
0 ,
0 ,
1
1
l a
l a
7
4
4
7
7
4
4
7
0
9
7
0
0
7
9
0
R
R
W
W
1
1
r o
r o
r o
r o
r o
r o
r o
r o
o t
o t
0
0
k
k
R
R
H
L
D
D
R
R
P
P
e
e
s
P
s
P
1
1
s i
s i
4
0
0
4
Doc No. 25092, Rev. 00
a t
a t
9 ,
0 ,
0 ,
9 ,
CAT5132
n
n
7
7
0
0
7
7
c
0
9
7
0
c
0
7
9
0
e
e
f
f
+
+
+
+
+
+
+
+
r o
r o
7
7
7
7
7
7
7
7
0
0
0
0
0
0
0
0