CAT5115
PIN CONFIGURATION
PDIP 8-Lead (L), SOIC 8-Lead (V),
MSOP 8-Lead (Z)
¯¯¯
INC
¯
U/D
R
H
GND
1
2
3
4
8
V
CC
¯¯
CS
R
L
R
WB
7
6
5
PIN DESCRIPTIONS
Name Function
¯¯¯
INC
¯
U/D
R
H
GND
R
W
R
L
¯¯
CS
V
CC
Increment Control
Up/Down Control
Potentiometer High Terminal
Ground
Buffered Wiper Terminal
Potentiometer Low Terminal
Chip Select
Supply Voltage
CAT
TSSOP 8-Lead (Y)
¯¯
CS
V
CC
¯¯¯
INC
¯
U/D
1
2
3
4
8
R
L
R
WB
GND
R
H
7
6
5
TDFN 8-Pad
(ZD7)
Top View
¯¯¯
INC
1
¯
U/D
2
R
H
3
GND
4
8
V
CC
¯¯
7
CS
6
R
L
5
R
WB
CAT
PIN FUNCTION
¯¯¯
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 CAT5115 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 CAT5115 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
mechanical potentiometer's wiper. There are 32
available tap positions including the resistor end
points, R
H
and R
L
. There are 31 resistor elements
connected in series between the R
H
and R
L
terminals.
The wiper terminal is connected to one of the 32 taps
¯¯¯
¯
¯¯
and controlled by three inputs, INC, U/D and CS.
These inputs control a five-bit up/down counter whose
output is decoded to select the wiper position.
¯¯
With CS set LOW the CAT5115 is selected and will
¯
¯¯¯
respond to the U/D and INC inputs. HIGH to LOW
¯¯¯
transitions on INC will increment or decrement the
¯
wiper (depending on the state of the U/D input and
five-bit counter). The wiper, when at either fixed
terminal, acts like its mechanical equivalent and does
not move beyond the last position. When the
CAT5115 is powered-down, the wiper position is
reset. When power is restored, the counter is set to
the mid point, tap 15.
Doc. No. MD-2117 Rev. G
2
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CATALYST [ CATALYST SEMICONDUCTOR ]
