CAT5116_07 Datasheet, PDF (2/12 Pages) Catalyst Semiconductor – Log-Taper, 100-Tap Digitally Programmable Potentiometer (DPP™)

CAT5116
PIN CONFIGURATION
PDIP 8-Lead (L)
SOIC 8 Lead (V)
MSOP 8 Lead (Z)
I¯N¯C¯ 1
8 V_CC
U/D¯
2
7
CAT
C¯¯S
R_H 3
6 R_L
GND 4
5 R_WB
TSSOP 8 Lead (Y)
C¯¯S 1
8 R_L
V_CC 2
7 R_W
CAT
I¯N¯C¯ 3
6 GND
U/D¯ 4
5 R_H
PIN DESCRIPTION
I¯N¯C¯: Increment Control Input
The I¯N¯C¯ 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 C¯¯S is low, any
high-to-low transition on I¯N¯C¯ will cause the wiper to
move one increment toward the R_H terminal. When in
a low state and C¯¯S is low, any high-to-low transition
on I¯N¯C¯ 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, I¯N¯C¯, U/D¯ and C¯¯S. 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.
PIN DESCRIPTIONS
Name Function
I¯N¯C¯ Increment Control
U/D¯ Up/Down Control
R_H Potentiometer High Terminal
GND Ground
R_W Buffered Wiper Terminal
R_L Potentiometer Low Terminal
C¯¯S Chip Select
V_CC Supply Voltage
C¯¯S: Chip Select
The chip select input is used to activate the control
input of the CAT5116 and is active low. When in a
high state, activity on the I¯N¯C¯ and U/D¯ inputs will not
affect or change the position of the wiper.
DEVICE OPERATION
The CAT5116 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 100 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 R_L terminals. The wiper terminal
is connected to one of the 100 taps and controlled by
three inputs, I¯N¯C¯, U/D¯ and C¯¯S. 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 nonvolatile memory using
the I¯N¯C¯ and C¯¯S inputs.
With C¯¯S set LOW the CAT5116 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 C¯¯S transitions
HIGH while the I¯N¯C¯ input is also HIGH. When the
CAT5116 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 I¯N¯C¯ set low, the CAT5116 may be deselected
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. MD-2118 Rev. K
2
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice