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CAT5115_07 Datasheet, PDF (2/14 Pages) Catalyst Semiconductor – 32-Tap Digitally Programmable Potentiometer (DPP™)
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CAT5115
PIN CONFIGURATION
PDIP 8-Lead (L), SOIC 8-Lead (V),
MSOP 8-Lead (Z)
I¯N¯C¯ 1
8 VCC
U/D¯
2
7
CAT
C¯¯S
RH 3
6 RL
GND 4
5 RWB
TSSOP 8-Lead (Y)
C¯¯S 1
8 RL
VCC 2
7 RWB
CAT
I¯N¯C¯ 3
6 GND
U/D¯ 4
5 RH
TDFN 8-Pad
(ZD7) Top View
I¯N¯C¯ 1
U/D¯ 2
RH 3
GND 4
8 VCC
7 C¯¯S
6 RL
5 RWB
PIN FUNCTION
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 RH 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 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, I¯N¯C¯, U/D¯ and C¯¯S. 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 DESCRIPTIONS
Name Function
I¯N¯C¯ Increment Control
U/D¯ Up/Down Control
RH Potentiometer High Terminal
GND Ground
RW Buffered Wiper Terminal
RL Potentiometer Low Terminal
C¯¯S Chip Select
VCC Supply Voltage
C¯¯S: 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 I¯N¯C¯ 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, I¯N¯C¯, U/D¯ and C¯¯S.
These inputs control a five-bit up/down counter whose
output is decoded to select the wiper position.
With C¯¯S set LOW the CAT5115 is selected and will
respond to the U/D¯ and I¯N¯C¯ inputs. HIGH to LOW
transitions on I¯N¯C¯ 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
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