CAT5126
One‐time Digital 32‐tap
Potentiometer (POT)
Description
The CAT5126 is a digital POT. The wiper position is controlled with
a simple 2-wire digital interface. This digital potentiometer is unique
in that it has an optional one-time programmable feature that either
sets the wiper’s position upon power-on to a user-defined value, or the
wiper can be set and the interface also disabled to prevent further
adjustment.
The CAT5126 has an end-to-end resistance of 10 kW, 50 kW, and
100 kW. All CAT5126 devices have 32-wiper positions and operate
from a single 2.5 V to 5.5 V supply.
The CAT5126 is available in TDFN 8-pad and MSOP 8-lead
packages. Each device is guaranteed over the industrial temperature
range of
−40C
to +85C.
Features
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MSOP−8
Z SUFFIX
CASE 846AD
TDFN−8
VP2 SUFFIX
CASE 511AK
PIN CONFIGURATIONS
1
R
W
CS
V
DD
GND
MSOP (Z)
R
W
CS
V
DD
GND
1
R
H
R
L
U/D
V
PP
R
H
R
L
U/D
V
PP
Wiper Position Stored after One-time Non-volatile Programming
User-defined Power-On Wiper Position
32-tap Positions
Wiper Position Programmed through Simple 2-wire Serial Interface
Low 0.35
mA
(typ) Static Supply Current
2.5 V to 5.5 V Single-supply Operation
10 kW, 50 kW, and 100 kW End-to-End Resistances
50 ppm/C End-to-End Temperature Coefficient and 5 ppm/C
Ratiometric Temperature Coefficient
TDFN 8-pad (2
3 mm) and MSOP 8-lead Packages
These Devices are Pb-Free, Halogen Free/BFR Free and are RoHS
Compliant
Applications
TDFN (VP2)
(Top Views)
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 9 of this data sheet.
Mechanical Potentiometer Replacement
Products using One-time Factory Calibration
Contrast, Brightness, Volume Controls
Programmable Analog Functions
Semiconductor Components Industries, LLC, 2013
June, 2013
−
Rev. 4
1
Publication Order Number:
CAT5126/D
CAT5126
R
H
V
DD
GND
3
R
31
8
4
2
UP/DOWN
COUNTER
6
32−POSITION
DECODER
ONE−TIME
PROGRAM
BLOCK
CS
U/D
R
30
R
W
1
R
W
V
PP
5
R
2
R
1
R
L
7
Figure 1. Functional Diagram
Table 1. PIN DESCRIPTION
Pin
1
2
3
4
5
6
7
8
Name
R
W
CS
V
DD
GND
V
PP
U/D
R
L
R
H
Wiper Connection
Chip-Select Input. A high-to-low CS transition determines the mode: increment if U/D is high, or decrement if
U/D is low. CS is also used for one-time programming (see the One-Time Programming section).
Power−Supply Voltage
Ground
Programming Voltage for One-Time Programming. Connect V
PP
to 10 V supply when one-time programming
the device. For normal operation, connect to ground or let float.
Up/Down Control Input. With CS low, a low-to-high transition increments or decrements the wiper position.
Low Terminal of Resistor
High Terminal of Resistor
Function
Table 2. ABSOLUTE MAXIMUM RATINGS
Parameters
V
DD
to GND
V
PP
to GND
All other pins to GND
Maximum Continuous Current into H, L, and W
Continuous Power Dissipation (T
A
= +70C)
MSOP 8-lead (derate 4.5 mW/C above +70C)
TDFN 8-pad (derate 24.4 mW/C above +70C)
Operating Temperature Range
Junction Temperature
Storage Temperature Range
Lead Temperature (soldering, 10 s)
Ratings
−0.5
to +7.0
−0.5
to +12.0
−0.5
to V
DD
+0.5
1.5
362
1951
−40
to +85
+150
−65
to +150
+300
Units
V
V
V
mA
mW
C
C
C
C
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
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CAT5126
Table 3. ELECTRICAL CHARACTERISTICS
(V
DD
= 2.5 V to 5.5 V, V
PP
= GND, R
H
= V
DD
, R
L
= GND, T
A
=
−40C
to +85C,
unless otherwise noted. Typical values are at V
DD
= 5.0 V, T
A
= +25C, unless otherwise noted.) (Note 1)
Symbol
DC PERFORMANCE
RES
R
POT
Resolution
End−to−End Resistance
−10
Device
−50
Device
−00
Device
TC
RPOT
TC
RATIO
INL
DNL
R
W
TC of Pot Resistance
Ratiometric Resistance TC
Integral Nonlinearity
Differential Nonlinearity
Wiper Resistance
Potentiometer configuration, no load
Potentiometer configuration, no load
V
DD
= 5 V
V
DD
= 2.5 V
DIGITAL INPUTS (CS, U/D)
V
IH
V
IL
I
IN
C
IN
V
DD
I
DD
I
DDW
V
PP
I
PP
t
CU
t
CI
t
IC
t
IL
t
IH
t
IW
t
PC
t
CP
t
CL
t
CH
t
PH
f
U/DMAX
1.
2.
3.
4.
Input High Voltage
Input Low Voltage
Input Leakage Current
Input Capacitance
0.1
5
0.7 x V
DD
0.3 x V
DD
1
V
V
mA
pF
8
40
80
3.2
10
50
100
50
5
0.5
0.25
70
150
12
60
120
300
20
1
0.5
100
200
ppm/C
ppm/C
LSB
LSB
W
%
kW
Parameter
Conditions
Min
Typ
Max
Units
POWER SUPPLY
Supply Voltage
Stand by Current
Programming Current
Programming Voltage
V
DD
= 5 V
V
DD
= 2.5 V
V
PP
Input Current
U/D Mode to CS Setup
CS Hold to U/D Mode
U/D Step Hold to CS
U/D Step Low Time
U/D Step High Time
Wiper Switching Time
V
PP
Rising Edge to CS
Falling Edge
CS Falling Edge to V
PP
Falling Edge
CS Step Low Time
CS Step High Time
V
PP
Falling Edge to CS
Rising Edge
U/D Frequency
V
PP
= 10 V
Figures 6, 7
Figures 6, 7
Figures 6, 7
Figures 6, 7
Figures 6, 7
C
L
= 0 pF, Figures 6, 7
Figure 8
Figure 8
Figure 8
Figure 8
Figure 8
1
5
5
5
1
5
50
50
0
100
100
100
TIMING CHARACTERISTICS
(Note 3)
ns
ns
ns
ns
ns
ns
ms
ms
ms
ms
ms
MHz
(Note 2)
2.5
0.35
0.25
8.5
6.0
5.5
1
1
10
10
5
mA
V
mA
mA
V
All devices are production tested at T
A
= +25C and are guaranteed by design for T
A
=
−40C
to +85C.
Digital inputs CS and U/D are connected to GND or V
DD
.
Digital timing is guaranteed by design, not production tested.
Power-up time is the period of time from when the power supply is applied until the serial interface is ready for writing.
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CAT5126
Table 3. ELECTRICAL CHARACTERISTICS
(V
DD
= 2.5 V to 5.5 V, V
PP
= GND, R
H
= V
DD
, R
L
= GND, T
A
=
−40C
to +85C,
unless otherwise noted. Typical values are at V
DD
= 5.0 V, T
A
= +25C, unless otherwise noted.) (Note 1) (continued)
Symbol
Parameter
Conditions
Min
Typ
Max
Units
TIMING CHARACTERISTICS
(Note 3)
t
UP
t
SETTLE
Power-up Time
Output Settling Time
(Note 4)
100 kW variable resistor
configuration, C
L
= 10 pF
100 kW potentiometer configuration,
C
L
= 10 pF
1.
2.
3.
4.
1
0.25
1
ms
ms
All devices are production tested at T
A
= +25C and are guaranteed by design for T
A
=
−40C
to +85C.
Digital inputs CS and U/D are connected to GND or V
DD
.
Digital timing is guaranteed by design, not production tested.
Power-up time is the period of time from when the power supply is applied until the serial interface is ready for writing.
TYPICAL OPERATING CHARACTERISTICS
(V
DD
= 2.5 V to 5.5 V, V
PP
= GND, V
H
= V
DD
, V
L
= GND, T
A
= +25C)
10
9
8
7
6
5
Invalid
Programming
Valid
Programming
I
CC
(mA)
2.5
3.5
V
DD
(V)
4.5
5.5
300
250
V
PP
(V)
200
150
100
2.5
3.5
V
DD
(V)
4.5
5.5
Figure 2. V
PP
vs. V
DD
120
V
DD
= 2.5 V
100
80
R
W
(W)
60
40
20
0
V
DD
= 5.0 V
V
W
(V)
5
4
3
2
6
Figure 3. I
DD
Programming vs. V
DD
V
DD
= 5.0 V
V
DD
= 2.5 V
1
0
0
10
TAP POSITION
20
30
0
10
TAP
20
30
Figure 4. Wiper Resistance vs.
Tap Position @ 255C
Figure 5. Wiper Voltage vs. Tap Position
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CAT5126
Detailed Description
The CAT5126 devices are 10 kW/50 kW/100 kW
(end-to-end resistance) digitally controlled potentiometers.
They have 32-tap positions that are accessible to the wiper
along the resistor array between R
H
and R
L
.
The wiper (R
W
) position is adjusted sequentially through
the tap positions using a simple I
2
C interface. These digital
potentiometers have an optional one-time programmable
feature that sets the POR position of the wiper. The I
2
C
interface can then be disabled, permanently preventing
unwanted adjustment.
Digital Interface Operation
The value of the counter is then stored and the wiper
position is maintained till the device is Powered down.
The wiper performs a make-before-break transition,
ensuring that there is never an open circuit during a
transition from one resistor tap to another. When the wiper
is at either end (max/min) of the resistor array, additional
transitions in the direction of the endpoint do not change the
counter value (the counter does not wrap around).
One−Time Programming
The CAT5126 devices have two modes of operation when
the serial interface is active: increment mode and decrement
mode. The serial interface is only active when CS is low.
The CS and U/D inputs control the position of the wiper
along the resistor array. When CS transitions from high to
low, the part goes into increment mode if U/D is high
(Figure 6), and into decrement mode if U/D is low
(Figure 7). Once the mode is set, the device remains in that
mode until CS goes high. A low-to-high transition at the U/D
increments or decrements the wiper position depending on
the current mode.
V
DD
CS
The factory-set default position of the wiper on power-up
is tap 16. However, the power-up position can be changed
once using the one-time programming feature. After the
wiper is moved to the desired position, the programming
sequence is initiated by setting U/D high, applying 10 V to
V
PP
, and then taking CS low. Five pulses on CS (consisting
of CS starting from low and going high for t
CH
and then low
for t
CL
) program the device (Figure 8). The programming
voltage should then be taken to zero. After the device is
programmed, V
PP
can be set to zero or be allowed to float.
The wiper position is still adjustable, but always returns to
this programmed position on power−up.
t
UP
t
CU
t
CI
t
IL
t
IH
t
IC
U/D
t
IW
V
W
Figure 6. Increment Mode Serial Interface Timing Diagram
V
DD
CS
t
UP
U/D
t
CU
t
CI
t
IH
t
IW
t
IL
t
IC
V
W
Figure 7. Decrement Mode Serial Interface Timing Diagram
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