CAT5112
32-Tap Digitally Programmable Potentiometer (DPP™)
with Buffered Wiper
FEATURES
32-position linear taper potentiometer
Non-volatile EEPROM wiper storage;
buffered wiper
Low power CMOS technology
Single supply operation: 2.5V-6.0V
Increment up/down serial interface
Resistance values: 10kΩ, 50kΩ and 100kΩ
Available in PDIP, SOIC, TSSOP and MSOP
packages
DESCRIPTION
The CAT5112 is a single digitally programmable
potentiometer (DPP™) designed as a electronic
replacement for mechanical potentiometers. Ideal for
automated adjustments on high volume production
lines, they are also well suited for applications where
equipment requiring periodic adjustment is either
difficult to access or located in a hazardous or remote
environment.
The CAT5112 contains a 32-tap series resistor array
connected between two terminals R
H
and R
L
. An
up/down counter and decoder that are controlled by
three input pins, determines which tap is connected to
the wiper, R
WB
. The CAT5112 wiper is buffered by an
op amp that operates rail to rail. The wiper setting,
stored in non-volatile memory, is not lost when the
device is powered down and is automatically recalled
when power is returned. The wiper can be adjusted to
test new system values without effecting the stored
setting.
Wiper-control
of
the
CAT5112
is
¯¯
¯
accomplished with three input control pins, CS, U/D,
¯¯¯
¯¯¯
and INC. The INC input increments the wiper in the
direction which is determined by the logic state of the
¯
¯¯
U/D input. The CS input is used to select the device
and also store the wiper position prior to power down.
The digitally programmable potentiometer can be
used as a buffered voltage divider. For applications
where the potentiometer is used as a 2-terminal
variable resistor, please refer to the CAT5114. The
buffered wiper of the CAT5112 is not compatible with
that application.
APPLICATIONS
Automated product calibration
Remote control adjustments
Offset, gain and zero control
Tamper-proof calibrations
Contrast, brightness and volume controls
Motor controls and feedback systems
Programmable analog functions
For Ordering Information details, see page 10.
FUNCTIONAL DIAGRAM
R
H
V
CC
R
H
U/D
INC
CS
Power On Recall
Control
and
Memory
+
R
WB
+
–
R
L
R
L
Electronic Potentiometer Implementation
R
WB
–
GND
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. MD-2002 Rev. M
CAT5112
PIN CONFIGURATION
PDIP 8-Lead (L)
SOIC 8 Lead (V)
MSOP 8 Lead (Z)
¯¯¯
INC
1
¯
U/D
2
R
H
3
GND
4
8
V
CC
¯¯
7
CS
6
R
L
5
R
WB
PIN DESCRIPTIONS
Name Function
TSSOP 8 Lead (Y)
¯¯
CS
1
V
CC
2
¯¯¯
INC
3
¯
U/D
4
8
R
L
7
R
WB
6
GND
5
R
H
¯¯¯
INC
¯
U/D
R
H
R
WB
R
L
¯¯
CS
V
CC
Increment Control
Up/Down Control
Potentiometer High Terminal
Buffered Wiper Terminal
Potentiometer Low Terminal
Chip Select
Supply Voltage
CAT
CAT
GND Ground
PIN DESCRIPTION
¯¯¯
INC:
Increment Control Input
¯¯¯
The INC input (on the falling edge) 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 CS is low, any
¯¯¯
high-to-low transition on INC will cause the wiper to
move one increment toward the R
H
terminal. When in
¯¯
a low state and CS is low, any high-to-low transition
¯¯¯
on INC 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
WB
:
Wiper Potentiometer Terminal (Buffered)
R
WB
is the buffered wiper terminal of the potentio–
meter. Its position on the resistor array is controlled by
¯¯¯
¯
¯¯
the control inputs, INC, U/D and CS.
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.
¯¯
CS:
Chip Select
The chip select input is used to activate the control
input of the CAT5112 and is active low. When in a
¯¯¯
¯
high state, activity on the INC and U/D inputs will not
affect or change the position of the wiper.
DEVICE OPERATION
The CAT5112 operates like a digitally controlled
potentiometer with R
H
and R
L
equivalent to the high
and low terminals and R
WB
equivalent to the mecha–
nical potentiometer's wiper. There are 32 available tap
positions including the resistor end points, R
H
and R
L
.
There are 31 resistor elements connected in series
between the R
H
and R
L
terminals. The wiper terminal
is connected to one of the 32 taps and controlled by
¯¯¯
¯
¯¯
three inputs, INC, U/D and CS. These inputs control a
five-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 CAT5112 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
five-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 CAT5112 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 CAT5112 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 non-
volatile memory.
Doc. No. MD-2002 Rev. M
2
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT5112
OPERATION MODES
¯¯¯
INC
High to Low
High to Low
High
Low
X
¯¯
CS
Low
Low
Low to High
Low to High
High
¯
U/D
High
Low
X
X
X
Operation
Wiper toward R
H
Wiper toward R
L
Store Wiper Position
No Store, Return to Standby
Standby
C
L
R
L
Potentiometer
Equivalent Circuit
C
H
R
WI
R
WB
C
W
R
H
ABSOLUTE MAXIMUM RATINGS
(1)
Parameters
Supply Voltage
V
CC
to GND
Inputs
¯¯
CS to GND
¯¯¯
INC to GND
¯
U/D to GND
R
H
to GND
R
L
to GND
R
WB
to GND
Symbol
V
ZAP(2)
I
LTH(2) (3)
T
DR
N
END
Ratings
-0.5 to +7V
-0.5 to V
CC
+0.5
-0.5 to V
CC
+0.5
-0.5 to V
CC
+0.5
-0.5 to V
CC
+0.5
-0.5 to V
CC
+0.5
-0.5 to V
CC
+0.5
Units
V
V
V
V
V
V
V
Parameters
Operating Ambient Temperature
Commercial (‘C’ or Blank suffix)
Industrial (‘I’ suffix)
Junction Temperature
Storage Temperature
Lead Soldering (10s max)
Ratings
0 to 70
-40 to +85
+150
-65 to 150
+300
Units
ºC
ºC
ºC
ºC
ºC
RELIABILITY CHARACTERISTICS
Parameter
ESD Susceptibility
Latch-Up
Data Retention
Endurance
Test Method
MIL-STD-883, Test Method 3015
JEDEC Standard 17
MIL-STD-883, Test Method 1008
MIL-STD-883, Test Method 1003
Min
2000
100
100
1,000,000
Typ
Max
Units
V
mA
Years
Stores
DC ELECTRICAL CHARACTERISTICS
V
CC
= +2.5V to +6V unless otherwise specified
Power Supply
Symbol
V
CC
I
CC1
I
CC2
I
SB1(3)
Parameter
Operating Voltage Range
Supply Current (Increment)
Supply Current (Write)
Supply Current (Standby)
V
CC
= 6V, f = 1MHz, I
W
= 0
V
CC
= 6V, f = 250kHz, I
W
= 0
Programming, V
CC
= 6V
V
CC
= 3V
¯¯
CS = V
CC
- 0.3V
¯ ¯¯¯
U/D, INC = V
CC
- 0.3V or GND
Conditions
Min
2.5
–
–
–
–
–
Typ
–
–
–
–
–
75
Max
6
200
100
1000
500
150
Units
V
µA
µA
µA
µA
µA
Notes:
(1) Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions outside of those listed in the operational sections of this
specification is not implied. Exposure to any absolute maximum rating for extended periods may affect device performance and reliability.
(2)
(3)
(4)
(5)
This parameter is tested initially and after a design or process change that affects the parameter.
Latch-up protection is provided for stresses up to 100mA on address and data pins from -1V to V
CC
+ 1V
I
W
= source or sink
These parameters are periodically sampled and are not 100% tested.
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
3
Doc. No. MD-2002 Rev. M
CAT5112
Logic Inputs
Symbol
I
IH
I
IL
V
IH1
V
IL1
V
IH2
V
IL2
Parameter
Input Leakage Current
Input Leakage Current
TTL High Level Input Voltage
TTL Low Level Input Voltage
CMOS High Level Input Voltage
CMOS Low Level Input Voltage
Conditions
V
IN
= V
CC
V
IN
= 0V
4.5V
≤
V
CC
≤
5.5V
2.5V
≤
V
CC
≤
6V
Min
–
–
2
0
V
CC
x 0.7
-0.3
Typ
–
–
–
–
–
–
Max
10
-10
V
CC
0.8
V
CC
+ 0.3
V
CC
x 0.2
Units
µA
µA
V
V
V
V
Potentiometer Characteristics
Symbol
R
POT
Parameter
Potentiometer Resistance
Pot. Resistance Tolerance
V
RH
V
RL
INL
DNL
R
OUT
I
OUT
TC
RPOT
TC
RATIO
C
RH
/C
RL
/C
RW
fc
V
WB(SWING)
Voltage on R
H
pin
Voltage on R
L
pin
Resolution
Integral Linearity Error
Differential Linearity Error
Buffer Output Resistance
Buffer Output Current
TC of Pot Resistance
Ratiometric TC
Potentiometer Capacitances
Frequency Response
Output Voltage Range
Passive Attenuator, 10kΩ
I
OUT
≤
100µA, V
CC
= 5V
0.01V
CC
I
W
≤
2µA
I
W
≤
2µA
0.05V
CC
≤
V
WB
≤
0.95V
CC
,
V
CC
= 5V
0.05V
CC
≤
V
WB
≤
0.95V
CC
,
V
CC
= 5V
300
20
8/8/25
1.7
0.99V
CC
0
0
1
0.5
0.25
1
0.5
1
3
Conditions
-10 Device
-50 Device
-00 Device
Min
Typ
10
50
100
±20
V
CC
V
CC
%
V
V
%
LSB
LSB
Ω
mA
ppm/ºC
ppm/ºC
pF
MHz
kΩ
Max
Units
Doc. No. MD-2002 Rev. M
4
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT5112
AC CONDITIONS OF TEST
V
CC
Range
Input Pulse Levels
Input Rise and Fall Times
Input Reference Levels
2.5V
≤
V
CC
≤
6V
0.2V
CC
to 0.7V
CC
10ns
0.5V
CC
AC OPERATING CHARACTERISTICS
V
CC
= +2.5V to +6.0V, V
H
= V
CC
, V
L
= 0V, unless otherwise specified
Symbol
t
CI
t
DI
t
ID
t
IL
t
IH
t
IC
t
CPH
t
CPH
t
IW
t
CYC
t
R
, t
F(2)
t
PU(2)
t
WR
Parameter
¯¯
¯¯¯
CS to INC Setup
¯ ¯¯¯
U/D to INC Setup
¯ ¯¯¯
U/D to INC Hold
¯¯¯
INC LOW Period
¯¯¯
INC HIGH Period
¯¯¯
¯¯
INC Inactive to CS Inactive
¯¯
CS Deselect Time (NO STORE)
¯¯
CS Deselect Time (STORE)
¯¯¯
INC to V
OUT
Change
¯¯¯
INC Cycle Time
¯¯¯
INC Input Rise and Fall Time
Power-up to Wiper Stable
Store Cycle
Min
100
50
100
250
250
1
100
10
–
1
–
–
–
Typ
(1)
–
–
–
–
–
–
–
–
1
–
–
–
5
Max
–
–
–
–
–
–
–
–
5
–
500
1
10
Units
ns
ns
ns
ns
ns
µs
ns
ms
µs
µs
µs
ms
ms
A.C. TIMING
CS
(store)
t
CPH
90%
10%
t
DI
U /D
t
ID
t
F
t
R
90%
t
CI
INC
t
IL
t
CYC
t
IH
t
IC
t
IW
R
WB
MI
(3)
Notes:
(1)
(2)
(3)
Typical values are for T
A
= 25ºC and nominal supply voltage.
This parameter is periodically sampled and not 100% tested.
MI in the A.C. Timing diagram refers to the minimum incremental change in the W output due to a change in the wiper position.
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
5
Doc. No. MD-2002 Rev. M
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