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CAT5115 Datasheet, PDF (2/9 Pages) Catalyst Semiconductor – 32-Tap Digitally Programmable Potentiometer
CAT5115
PIN CONFIGURATION
DIP Package (P, L)
INC 1
U/D 2
RH 3
GND 4
8 VCC
7 CS
6 RL
5 RW
TSSOP Package (U, Y)
CS 1
VCC 2
INC 3
U/D 4
8 RL
7 RW
6 GND
5 RH
SOIC Package (S, V)
INC 1
U/D 2
RH 3
GND 4
8 VCC
7 CS
6 RL
5 RW
MSOP Package (R, Z)
INC 1
U/D 2
RH 3
GND 4
8 VCC
7 CS
6 RL
5 RW
PIN DESCRIPTIONS
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 RH 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
RL terminal.
RH: High End Potentiometer Terminal
RH is the high end terminal of the potentiometer. It is not
required that this terminal be connected to a potential
greater than the RL terminal. Voltage applied to the RH
terminal cannot exceed the supply voltage, VCC or go
below ground, GND.
RW: Wiper Potentiometer Terminal
RW 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 RW terminal cannot
exceed the supply voltage, VCC or go below ground, GND.
RL: Low End Potentiometer Terminal
RL is the low end terminal of the potentiometer. It is not
required that this terminal be connected to a potential
less than the RH terminal. Voltage applied to the RL
terminal cannot exceed the supply voltage, VCC or go
below ground, GND. RL and RH are electrically
interchangeable.
PIN FUNCTIONS
Pin Name
Function
INC
Increment Control
U/D
Up/Down Control
RH
Potentiometer High Terminal
GND
Ground
RW
Potentiometer Wiper Terminal
RL
Potentiometer Low Terminal
CS
Chip Select
VCC
Supply Voltage
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 RH and RL equivalent to the high
and low terminals and RW equivalent to the mechanical
potentiometer's wiper. There are 32 available tap
positions including the resistor end points, RH and RL.
There are 31 resistor elements connected in series
between the RH 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 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 wil 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. 2117, Rev. E
2