CAT5114 Datasheet, PDF (2/6 Pages) Catalyst Semiconductor – 32-Tap Digitally Programmable Potentiometer (DPP)

CAT5114
Advance Information
PIN CONFIGURATION
DIP/SOIC Package
INC
U/D
R_H
GND
V_CC
CS
R_L
R_W
TSSOP Package
CS
V_CC
INC
U/D
R_L
R_W
GND
R_H
MSOP Package
INC
V_CC
U/D
CS
R_H
RL
GND
R_W
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.
R_H: 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
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.
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.
CS: Chip Select
The chip select input is used to activate the control input
PIN FUNCTIONS
Pin Name
Function
INC
Increment Control
U/D
Up/Down Control
R_H
Potentiometer High Terminal
GND
Ground
R_W
Potentiometer Wiper Terminal
R_L
Potentiometer Low Terminal
CS
Chip Select
V_CC
Supply Voltage
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 mechanical
potentiometer's wiper. There are 32 available tap posi-
tions 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. The selected wiper position can be
stored in nonvolatile 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 five-
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 nonvolatile memory.
Doc. No. 25091-00 Rev. 3/01
M-1
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