CAT5113
Doc. No. MD-2009 Rev. Y 2 © 2009 SCILLC. All rights reserved.
Characteristics subject to change without notice
PIN CONFIGURATION
PDIP 8-Lead (L)
SOIC 8 Lead (V)
MSOP 8 Lead (Z)
INC
¯¯¯
1
8
V
CC
U/D
¯
2
7
CS
¯¯
R
H
3
6
R
L
GND
4
5
R
WB
CAT
TSSOP 8 Lead (Y)
CS
¯¯
1
8
R
L
V
CC
2
7
R
WB
INC
¯¯¯
3
6
GND
U/D
¯
4
5
R
H
CAT
PIN DESCRIPTIONS
Name Function
INC
¯¯¯
Increment Control
U/D
¯
Up/Down Control
R
H
Potentiometer High Terminal
GND Ground
R
W
Wiper Terminal
R
L
Potentiometer Low Terminal
CS
¯¯
Chip Select
V
CC
Supply Voltage
PIN DESCRIPTION
INC
¯¯¯
: Increment Control Input
The INC
¯¯¯
input moves the wiper in the up or down
direction determined by the condition of the U/D
¯
input.
U/D
¯
: Up/Down Control Input
The U/D
¯
input controls the direction of the wiper
movement. When in a high state and CS
¯¯
is low, any
high-to-low transition on INC
¯¯¯
will cause the wiper to
move one increment toward the R
H
terminal. When in
a low state and CS
¯¯
is low, any high-to-low transition
on INC
¯¯¯
will cause the wiper to move one increment
towards the R
L
terminal.
R
H
: High End Potentiometer Terminal
R
H
is the high end terminal of the potentiometer. It is
not required that this terminal be connected to a
potential greater than the R
L
terminal. Voltage applied
to the R
H
terminal cannot exceed the supply voltage,
V
CC
or go below ground, GND.
R
W
: Wiper Potentiometer Terminal
R
W
is the wiper terminal of the potentiometer. Its
position on the resistor array is controlled by the
control inputs, INC
¯¯¯
, U/D
¯
and CS
¯¯
. Voltage applied to
the R
W
terminal cannot exceed the supply voltage,
V
CC
or go below ground, GND.
R
L
: Low End Potentiometer Terminal
R
L
is the low end terminal of the potentiometer. It is
not required that this terminal be connected to a
potential less than the R
H
terminal. Voltage applied to
the R
L
terminal cannot exceed the supply voltage, V
CC
or go below ground, GND. R
L
and R
H
are electrically
interchangeable.
CS
¯¯
: Chip Select
The chip select input is used to activate the control
input of the CAT5113 and is active low. When in a
high state, activity on the INC
¯¯¯
and U/D
¯
inputs will not
affect or change the position of the wiper.
DEVICE OPERATION
The CAT5113 operates like a digitally controlled
potentiometer with R
H
and R
L
equivalent to the high
and low terminals and R
W
equivalent to the mecha–
nical potentiometer's wiper. There are 100 available
tap positions including the resistor end points, R
H
and
R
L
. There are 99 resistor elements connected in
series between the R
H
and RL terminals. The wiper
terminal is connected to one of the 100 taps and
controlled by three inputs, INC
¯¯¯
, U/D
¯
and CS
¯¯
. These
inputs control a seven-bit up/down counter whose
output is decoded to select the wiper position. The
selected wiper position can be stored in non-volatile
memory using the INC
¯¯¯
and CS
¯¯
inputs.
With CS
¯¯
set LOW the CAT5113 is selected and will
respond to the U/D
¯
and INC
¯¯¯
inputs. HIGH to LOW
transitions on INC
¯¯¯
wil increment or decrement the
wiper (depending on the state of the U/D
¯
input and
seven-bit counter). The wiper, when at either fixed
terminal, acts like its mechanical equivalent and does
not move beyond the last position. The value of the
counter is stored in nonvolatile memory whenever CS
¯¯
transitions HIGH while the INC
¯¯¯
input is also HIGH.
When the CAT5113 is powered-down, the last stored
wiper counter position is maintained in the nonvolatile
memory. When power is restored, the contents of the
memory are recalled and the counter is set to the
value stored.
With INC
¯¯¯
set low, the CAT5113 may be de-selected
and powered down without storing the current wiper
position in nonvolatile memory. This allows the system
to always power up to a preset value stored in non
-
volatile memory.
