CAT5127, CAT5129
32tap Digital
Potentiometers (POTs)
Description
The CAT5127/CAT5129 are single digital POTs designed as an
electronic replacement for mechanical potentiometers and trim pots. CAT5127, CAT5129
CAT5127 CAT5129
V
V
CC CC
R
P
R
H
(U/D)
R
H
(U/D)
Control
and
(INC)
Control
Memory
and
(INC)
Memory
(CS)
POR
(CS)
R
L
POR
GND GND
Figure 1. Functional Diagrams
Table 1. PIN DESCRIPTIONS
CAT5127 CAT5129
Name Function MSOP/TDFN SOT23
INC Increment Control 1 4
U/D Up/Down Control 2 3
R Potentiometer High Terminal 3 5
H
GND Ground 4 2
NC No Connect 5
R Potentiometer Low Terminal 6
L
CS Chip Select 7 1
V Supply Voltage 8 6
CC
DEVICE DESCRIPTION
INC: Increment Control Input R : Low End Potentiometer Terminal (CAT5127 only)
L
The INC input moves the wiper in the up or down R is the low end terminal of the potentiometer. It is not
L
direction determined by the condition of the U/D input. required that this terminal be connected to a potential less
than the R terminal. Voltage applied to the R terminal
H L
U/D: Up/Down Control Input
cannot exceed the supply voltage, V or go below ground,
CC
The U/D input controls the direction of the wiper
GND. R and R are electrically interchangeable.
L H
movement. When in a high state and CS is low, any
high-to-low transition on INC will cause the wiper to move CS: Chip Select
one increment toward the R terminal. When in a low state The chip select input is used to activate the control input
H
and CS is low, any high-to-low transition on INC will cause of the device and is active low. When in a high state, activity
the wiper to move one increment towards the R terminal. on the INC and U/D inputs will not affect or change the
L
position of the wiper. CAT5127 has an internal pull-up
R : High End Potentiometer Terminal
H
resistor on the CS input pin.
R is the high end terminal of the potentiometer. It is not
H
required that this terminal be connected to a potential greater V : Supply Input for the device.
CC
than the R terminal. Voltage applied to the R terminal
L H
cannot exceed the supply voltage, V or go below ground,
CC
GND.