CAT5114
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
R
W
R
L
¯¯
CS
V
CC
Increment Control
Up/Down Control
Potentiometer High Terminal
Buffered Wiper Terminal
Potentiometer Low Terminal
Chip Select
Supply Voltage
CAT
GND Ground
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, VP2)
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 CAT5114 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
CAT5114 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 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 RL 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
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 CAT5114 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
CAT5114 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 CAT5114 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.
2
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
Doc. No. MD-2007 Rev. O
CATALYST [ CATALYST SEMICONDUCTOR ]
