CAT5112
32-Tap Digitally Programmable Potentiometer (DPP™)
with Buffered Wiper
FEATURES
s
32-position linear taper potentiometer
s
Non-volatile NVRAM wiper storage;
H
GEN
FR
ALO
EE
LE
A
D
F
R
E
E
TM
APPLICATIONS
s
Automated product calibration
s
Remote control adjustments
s
Offset, gain and zero control
s
Tamper-proof calibrations
s
Contrast, brightness and volume controls
s
Motor controls and feedback systems
s
Programmable analog functions
buffered wiper
s
Low power CMOS technology
s
Single supply operation: 2.5V-6.0V
s
Increment up/down serial interface
s
Resistance values: 10kΩ, 50kΩ and 100kΩ
Ω,
Ω
Ω
s
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 and trim
pots. 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 NVRAM memory, is not lost when the de-
vice is powered down and is automatically recalled when
power is returned. The wiper can be adjusted to test new
FUNCTIONAL DIAGRAM
V
CC
RH
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 appli-
cation. DPPs bring variability and programmability to a
broad range of applications and are used primarily to
control, regulate or adjust a characteristic or parameter
of an analog circuit.
R
H
U/D
INC
CS
Power On Recall
+
–
>
Control
and
Memory
+
–
RWB
R
WB
R
L
RL
V
SS
Electronic Potentiometer
Implementation
© 2004 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
Doc. No. 2002, Rev. L
1
CAT5112
PIN CONFIGURATION
PDIP Package (P, L)
INC
U/D
RH
GND
1
2
3
4
8
7
6
5
V
CC
CS
RL
RWB
PIN FUNCTIONS
TSSOP Package (U, Y)
CS
V
CC
INC
U/D
1
2
3
4
8
7
6
5
RL
RWB
GND
RH
Pin Name
INC
U/D
R
H
GND
Function
Increment Control
Up/Down Control
Potentiometer High Terminal
Ground
Buffered Wiper Terminal
Potentiometer Low Terminal
Chip Select
Supply Voltage
SOIC Package (S, V)
INC
U/D
RH
GND
1
2
3
4
8
7
6
5
V
CC
CS
RL
RWB
MSOP Package (R, Z)
INC
U/D
RH
GND
1
2
3
4
8
7
6
5
V
CC
CS
RL
RWB
R
WB
R
L
CS
V
CC
PIN DESCRIPTIONS
INC:
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
D
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 potentiometer. 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:
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 mechanical
potentiometer's wiper. There are 32 available tap posi-
tions 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 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. 2002, Rev. L
2
CAT5112
OPERATING MODES
R
H
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 H
Wiper toward L
Store Wiper Position
No Store, Return to Standby
Standby
C
H
R
wi
R
WB
C
W
C
L
R
L
Potentiometer
Equivalent Circuit
ABSOLUTE MAXIMUM RATINGS
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
-0.5V to +7V
-0.5V to V
CC
+0.5V
-0.5V to V
CC
+0.5V
-0.5V to V
CC
+0.5V
-0.5V to V
CC
+0.5V
-0.5V to V
CC
+0.5V
-0.5V to V
CC
+0.5V
Operating Ambient Temperature
Commercial (‘C’ or Blank suffix)
0°C to +70°C
Industrial (‘I’ suffix)
-40°C to +85°C
Junction Temperature
+150°C
Storage Temperature
-65°C to +150°C
Lead Soldering (10 sec max)
+300°C
* Stresses above those listed under Absolute Maximum Ratings may
cause permanent damage to the device. Absolute Maximum Ratings
are limited values applied individually while other parameters are
within specified operating conditions, and functional operation at any
of these conditions is NOT implied. Device performance and reliability
may be impaired by exposure to absolute rating conditions for extended
periods of time.
RELIABILITY CHARACTERISTICS
Symbol
V
ZAP(1)
I
LTH(1)(2)
T
DR
N
END
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
Volts
mA
Years
Stores
DC Electrical Characteristics: V
CC
= +2.5V to +6.0V unless otherwise specified
Power Supply
Symbol Parameter
Conditions
Min
V
CC
I
CC1
I
CC2
ISB
1 (2)
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
2.5
—
—
—
—
—
Typ
—
—
—
—
—
75
Max
6.0
200
100
1
500
150
Units
V
µA
mA
µA
µA
Logic Inputs
Symbol
I
IH
I
IL
V
IH1
V
IL1
V
IH2
V
IL2
NOTES:
(1)
(2)
(3)
(4)
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
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.
3
Doc. No. 2002, Rev. L
CAT5112
Potentiometer Parameters
Symbol
R
POT
Parameter
Potentiometer Resistance
Conditions
-10 Device
-50 Device
-00 Device
Pot Resistance Tolerance
V
RH
V
RL
Voltage on R
H
pin
Voltage on R
L
pin
Resolution
INL
DNL
R
OUT
I
OUT
TC
RPOT
TC
RATIO
R
ISO
Integral Linearity Error
Differential Linearity Error
Buffer Output Resistance
Buffer Output Current
TC of Pot Resistance
Ratiometric TC
Isolation Resistance
I
W
≤
2µA
I
W
≤
2µA
.05V
CC
≤
V
WB
≤
.95V
CC
, V
CC
=5V
.05V
CC
≤
V
WB
≤
.95V
CC
, V
CC
=5V
Min
Typ
10
50
100
Max
Units
kΩ
±20
%
V
V
%
1
0.5
1
3
LSB
LSB
Ω
mA
ppm/˚C
ppm/˚C
Ω
pF
MHz
.99V
CC
0
0
1
0.5
0.25
V
CC
V
CC
300
TBD
TBD
8/8/25
Passive Attenuator, 10kΩ
I
OUT
≤100µA,
V
CC
=5V
0.01V
CC
C
RH
/C
RL
/C
RW
Potentiometer Capacitances
fc
V
WB(SWING)
Frequency Response
Output Voltage Range
1.7
Doc. No. 2002, Rev. L
4
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
msec
ms
A. C. TIMING
CS
t
CYC
t
IL
t
IH
(store)
t
CI
INC
t
IC
t
CPH
90%
10%
90%
tDI
tID
U/D
t
F
t
R
t
IW
RW
MI (3)
(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 A.C. Timing diagram refers to the minimum incremental change in the W output due to a change in the wiper position.
5
Doc. No. 2002, Rev. L
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