CAT5116 Datasheet, PDF (6/8 Pages) Catalyst Semiconductor – Log-Taper, 100-Tap Digitally Programmable Potentiometer

CAT5116
AC Timing
CS
t_CI
INC
U/D
t_CYC
t_IL
t_IH
t_IC
tDI tID
(store)
t_CPH
90%
90%
10%
t_F
t_R
t_IW
MI ⁽³⁾
RW
(1) Typical values are for T_A=25˚C and nominal supply voltage.
(2) This parameter is periodically sampled and not 100% tested.
(3) MI in the AC Timing diagram refers to the minimum incremental change in the W output due to a change in the wiper position.
DEVICE OPERATION
The CAT5116 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 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 is 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 nonvolatile memory using the INC and
CS inputs.
With CS 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 CS
transitions HIGH while the INC 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 INC set low, the CAT5116 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. 2118, Rev. J
6
OPERATING MODES
INC
High to Low
High to Low
High
Low
X
CS
U/D
Low
High
Low
Low
Low to High X
Low to High X
High
X
Operation
Wiper Toward H
Wiper Toward L
Store Wiper Position
No Store, Return to Standby
Standby
X: High or Low
R_H
C_H
R_wi
R_W
C_W
C_L
R_L
Potentiometer
Equivalent Circuit