Digitally Controlled Potentiometer (XDCP™)
X9319
FEATURES
DESCRIPTION
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The Xicor X9319 is a digitally controlled potentiometer
(XDCP). The device consists of a resistor array, wiper
switches, a control section, and nonvolatile memory.
The wiper position is controlled by a 3-wire interface.
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•
•
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Solid-state potentiometer
3-wire serial interface
Terminal voltage, 0 to +10V
100 wiper tap points
—Wiper position stored in nonvolatile memory
and recalled on power-up
99 resistive elements
—Temperature compensated
—End to end resistance range ± 20%
Low power CMOS
—VCC = 5V
—Active current, 3mA max.
—Standby current, 1mA max.
High reliability
—Endurance, 100,000 data changes per bit
—Register data retention, 100 years
RTOTAL value = 10KΩ and 50KΩ
Packages
—8-lead SOIC and DIP
The potentiometer is implemented by a resistor array
composed of 99 resistive elements and a wiper switching network. Between each element and at either end
are tap points accessible to the wiper terminal. The
position of the wiper element is controlled by the CS,
U/D, and INC inputs. The position of the wiper can be
stored in nonvolatile memory and then be recalled
upon a subsequent power-up operation.
The device can be used as a three-terminal
potentiometer for voltage control or as a two-terminal
variable resistor for current control in a wide variety of
applications.
APPLICATIONS
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•
•
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•
LCD bias control
DC bias adjustment
Gain and offset trim
Laser diode bias control
Voltage regulator output control
BLOCK DIAGRAM
U/D
INC
CS
VCC (Supply Voltage)
Control
and
Memory
Device Select
(CS)
RH
99
98
97
RH
Up/Down
(U/D)
Increment
(INC)
Up/Down
Counter
7-Bit
Nonvolatile
Memory
RW
RL
96
One
of
One
Hundred
Decoder
Wiper
Switches
Resistor
Array
2
VSS (Ground)
General
VCC
VSS
Store and
Recall
Control
Circuitry
1
0
RL
RW
Detailed
XDCP is a trademark of Xicor, Inc.
REV 1.7 7/10/03
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X9319
PIN CONFIGURATION
DIP/SOIC
INC
1
U/D
2
RH
3
VSS
4
X9319
8
VCC
7
CS
6
RL
5
RW
ORDERING INFO
Ordering
Number
RTOTAL
X9319WS8
10KΩ
8-lead SOIC
0°C to 70°C
X9319WS8I
10KΩ
8-lead SOIC
-40°C to +85°C
Package
Operating Temperature
Range
X9319WP8
10KΩ
8-lead Plastic DIP
0°C to 70°C
X9319WP8I
10KΩ
8-lead Plastic DIP
-40°C to +85°C
X9319US8
50KΩ
8-lead SOIC
0°C to 70°C
X9319US8I
50KΩ
8-lead SOIC
-40°C to +85°C
X9319UP8
50KΩ
8-lead Plastic DIP
0°C to 70°C
X9319UP8I
50KΩ
8-lead Plastic DIP
-40°C to +85°C
PIN DESCRIPTIONS
DIP/
SOIC
Symbol
1
INC
Increment. Toggling INC while CS is low moves the wiper either up or down.
2
U/D
Up/Down. The U/D input controls the direction of the wiper movement.
3
RH
The high terminal is equivalent to one of the fixed terminals of a mechanical potentiometer.
4
VSS
Ground.
5
RW
The wiper terminal is equivalent to the movable terminal of a mechanical potentiometer.
6
The low terminal is equivalent to one of the fixed terminals of a mechanical potentiometer.
7
RL
CS
8
VCC
Supply Voltage.
REV 1.7 7/10/03
Brief Description
Chip Select. The device is selected when the CS input is LOW, and de-selected when CS is
high.
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X9319
ABSOLUTE MAXIMUM RATINGS
COMMENT
Junction Temperature under bias ......–65°C to +135°C
Storage temperature .........................–65°C to +150°C
Voltage on CS, INC, U/D and VCC
with respect to VSS ................................. –1V to +7V
RH, RW, RL to ground .......................................... +12V
Lead temperature (soldering 10 seconds)..........300°C
IW (10 seconds) ................................................. ±6mA
Stresses above those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device.
This is a stress rating only; functional operation of the
device (at these or any other conditions above those
listed in the operational sections of this specification) is
not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
POTENTIOMETER CHARACTERISTICS
(VCC = 5V ±10%, TA = Full Operating Temperature Range unless otherwise stated)
Limits
Symbol
VRH/RL
Parameter
Min.
Typ.(4)
+20
%
See ordering information
for values
RH/RL terminal voltage
VSS
10
V
VSS = 0V
25
mW
Wiper resistance
IW
Wiper current(5)
Resolution
(1)
(2)
See test circuit
-120
dBV
Ref: 1kHz
1
%
-0.2
Relative linearity
RTOTAL temperature
coefficient(5)
+1
MI(3)
+0.2
MI(3)
±300
(5),(6)
Ratiometric temperature coefficient
REV 1.7 7/10/03
Ω
mA
-1
Absolute linearity
-20
Potentiometer capacitances
Supply Voltage
200
+3.0
40
-3.0
Noise(7)
VCC
Test Conditions/Notes
-20
RW
CH/CL/CW
Unit
End to end resistance tolerance
Power rating
(5)
Max.
10/10/25
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V(RH) = 10V,
V(RL) = 0V
ppm/°C
+20
4.5
IW = 1mA
ppm/°C
pF
5.5
See equivalent circuit
V
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X9319
D.C. OPERATING CHARACTERISTICS
(VCC = 5V ±10%, TA = Full Operating Temperature Range unless otherwise stated)
Limits
Symbol
Parameter
Typ.(4)
Max.
Unit
1
3
mA
CS = VIL, U/D = VIL or VIH and
INC = 0.4V/2.4V @ min. tCYC
RL, RH, RW not connected
300
1000
µA
CS ≥ 2.4V, U/D and INC = 0.4V
RL, RH, RW not connected
-10
+10
µA
VIN = VSS to VCC
Min.
ICC
VCC active current (Increment)
ISB
Standby supply current
ILI
CS, INC, U/D input leakage
current
VIH
CS, INC, U/D input HIGH voltage
2
VCC + 1
V
VIL
CS, INC, U/D input LOW voltage
–1
0.8
V
CIN(5)
CS, INC, U/D input capacitance
10
pF
Test Conditions
VCC = 5V, VIN = VSS, TA = 25°C,
f = 1MHz
ENDURANCE AND DATA RETENTION
(VCC = 5V ±10%, TA = Full Operating Temperature Range)
Parameter
Min.
Unit
Minimum endurance
100,000
Data changes per bit
Data retention
100
Years
Notes: (1) Absolute linearity is utilized to determine actual wiper voltage versus expected voltage = [V(R W(n)(actual))–V(RW(n)(expected))]/MI
V(RW(n)(expected)) = n(V(RH)-V(RL))/99 + V(RL), with n from 0 to 99.
(2) Relative linearity is a measure of the error in step size between taps = [V(RW(n+1))–(V(RW(n)) – MI)]/MI
(3) 1 Ml = Minimum Increment = [V(RH)–V(RL)]/99.
(4) Typical values are for TA = 25°C and nominal supply voltage.
(5) Guaranteed by device characterization.
(6) Ratiometric temperature coefficient = (V(RW)T1(n)–V(RW)T2(n))/[V(RW)T1(n)(T1–T2) x 106], with T1 & T2 being 2 temperatures,
and n from 0 to 99.
(7) Measured with wiper at tap position 31, RL grounded, using test circuit.
Test Circuit
Equivalent Circuit
RTOTAL
Test Point
RH
CW
CH
RW
Force
Current
CL
RL
10pF
25pF
10pF
RW
A.C. CONDITIONS OF TEST
Input pulse levels
0.8V to 2.0V
Input rise and fall times
10ns
Input reference levels
1.4V
REV 1.7 7/10/03
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X9319
A.C. OPERATING CHARACTERISTICS
(VCC = 5V ±10%, TA = Full Operating Temperature Range unless otherwise stated)
Limits
Symbol
tCl
Parameter
Min.
Typ.(4)
Max.
Unit
CS to INC setup
100
ns
tlD(5)
INC HIGH to U/D change
100
ns
tDI(5)
U/D to INC setup
1
µs
tlL
INC LOW period
1
µs
tlH
INC HIGH period
1
µs
tlC
INC inactive to CS inactive
1
µs
tCPHS
CS deselect time (STORE)
20
ms
CS deselect time (NO STORE)
1
µs
tCPHNS(5)
tIW(5)
INC to RW change
tCYC
INC cycle time
tR, tF(5)
tPU(5)
tR VCC(5)
100
500
µs
4
µs
INC input rise and fall time
500
µs
Power up to wiper stable
500
µs
50
V/ms
VCC power-up rate
0.2
POWER UP AND DOWN REQUIREMENTS
In order to prevent unwanted tap position changes, or an inadvertant store, bring the CS and INC high before or
concurrently with the VCC pin on powerup. The potentiometer voltages must be applied after this sequence is completed. During power-up, the data sheet parameters for the DCP do not fully apply until 1 millisecond after VCC
reaches its final value. The VCC ramp spec is always in effect.
A.C. TIMING
CS
tCYC
tCI
tIL
tIC
tIH
tCPHNS
tCPHS
90% 90%
10%
INC
tID
tDI
tF
tR
U/D
tIW
RW
REV 1.7 7/10/03
MI
(3)
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X9319
PIN DESCRIPTIONS
PIN NAMES
RH and RL
Symbol
The high (RH) and low (RL) terminals of the X9319 are
equivalent to the fixed terminals of a mechanical
potentiometer. The terminology of RL and RH references the relative position of the terminal in relation to
wiper movement direction selected by the U/D input
and not the voltage potential on the terminal.
RW
Rw is the wiper terminal and is equivalent to the movable terminal of a mechanical potentiometer. The position of the wiper within the array is determined by the
control inputs. The wiper terminal series resistance is
typically 40Ω.
Up/Down (U/D)
The U/D input controls the direction of the wiper movement and whether the counter is incremented or decremented.
Increment (INC)
The INC input is negative-edge triggered. Toggling INC
will move the wiper and either increment or decrement
the counter in the direction indicated by the logic level
on the U/D input.
Chip Select (CS)
The device is selected when the CS input is LOW. The
current counter value is stored in nonvolatile memory
when CS is returned HIGH while the INC input is also
HIGH. After the store operation is complete the X9319
will be placed in the low power standby mode until the
device is selected once again.
PIN CONFIGURATION
DIP/SOIC
8
VCC
7
CS
3
6
RL
4
5
RW
INC
1
U/D
2
RH
VSS
REV 1.7 7/10/03
X9319
Description
RH
High terminal
RW
Wiper terminal
RL
Low terminal
VSS
Ground
VCC
Supply voltage
U/D
Up/Down control input
INC
Increment control input
CS
Chip select control input
PRINCIPLES OF OPERATION
There are three sections of the X9319: the control
section, the nonvolatile memory, and the resistor array.
The control section operates just like an up/down
counter. The output of this counter is decoded to turn
on a single electronic switch connecting a point on the
resistor array to the wiper output. The contents of the
counter can be stored in nonvolatile memory and
retained for future use. The resistor array is comprised
of 99 individual resistors connected in series.
Electronic switches at either end of the array and
between each resistor provide an electrical connection
to the wiper pin, RW.
The wiper acts like its mechanical equivalent and does
not move beyond the first or last position. That is, the
counter does not wrap around when clocked to either
extreme.
The electronic switches on the device operate in a
“make before break” mode when the wiper changes
tap positions. If the wiper is moved several positions,
multiple taps are connected to the wiper for tIW (INC to
VW change). The RTOTAL value for the device can temporarily be reduced by a significant amount if the wiper
is moved several positions.
When the device is powered-down, the last wiper position stored will be maintained in the nonvolatile memory. When power is restored, the contents of the
memory are recalled and the wiper is set to the value
last stored.
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X9319
MODE SELECTION
INSTRUCTIONS AND PROGRAMMING
The INC, U/D and CS inputs control the movement of
the wiper along the resistor array. With CS set LOW the
device is selected and enabled to respond to the U/D
and INC inputs. HIGH to LOW transitions on INC will
increment or decrement (depending on the state of the
U/D input) the seven bit counter. The output of this
counter is decoded to select one of one hundred wiper
positions along the resistive array.
CS
INC
U/D
Mode
L
H
Wiper up
L
L
Wiper down
H
X
Store wiper position to
nonvolatile memory
X
X
Standby
L
X
No store, return to standby
L
H
Wiper Up (not recommended)
L
L
Wiper Down
(not recommended)
H
The value of the counter is stored in nonvolatile memory whenever CS transitions HIGH while the INC input
is also HIGH.
The system may select the X9319, move the wiper and
deselect the device without having to store the latest
wiper position in nonvolatile memory. After the wiper
movement is performed as described above and once
the new position is reached, the system must keep INC
LOW while taking CS HIGH. The new wiper position
will be maintained until changed by the system or until
a powerup/down cycle recalled the previously stored
data. This procedure allows the system to always
power-up to a preset value stored in nonvolatile memory; then during system operation minor adjustments
could be made. The adjustments might be based on
user preference, system parameter changes due to
temperature drift, etc.
The state of U/D may be changed while CS remains
LOW. This allows the host system to enable the device
and then move the wiper up and down until the proper
trim is attained.
REV 1.7 7/10/03
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X9319
APPLICATIONS INFORMATION
Electronic digitally controlled (XDCP) potentiometers provide three powerful application advantages; (1) the variability and reliability of a solid-state potentiometer, (2) the flexibility of computer-based digital controls, and (3) the
retentivity of nonvolatile memory used for the storage of multiple potentiometer settings or data.
Basic Configurations of Electronic Potentiometers
VREF
VREF
RH
RW
RL
I
Three terminal potentiometer;
variable voltage divider
Two terminal variable resistor;
variable current
Basic Circuits
Buffered Reference Voltage
Single Supply Inverting Amplifier
Cascading Techniques
R1
+V
+V
+V
R1
+5V
RW
VREF
+
VS
LMC7101
VOUT
–
+8V
R2
X
RW
–
100K
+V
VO
+
+10V
LMC7101
(a)
Voltage Regulator
VIN
100K
RW
VOUT = VW/RW
VO = (R2/R1)VS
(b)
Offset Voltage Adjustment
VO (REG)
317
R1
Comparator with Hysteresis
R2
VS
R1
VS
LT311A
+12V
100KΩ
–
+
VO
–
+
Iadj
10KΩ
10KΩ
VO (REG) = 1.25V (1+R2/R1)+Iadj R2
}
LMC7101
10KΩ
}
R2
VO
R1
R2
VUL = {R1/(R1+R2)} VO(max)
VLL = {R1/(R1+R2)} VO(min)
+15V
(for additional circuits see AN115)
REV 1.7 7/10/03
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X9319
PACKAGING INFORMATION
8-Lead Plastic Small Outline Package, Type S (8-lead SOIC)
0.150 (3.80) 0.228 (5.80)
0.158 (4.00) 0.244 (6.20)
Pin 1 Index
Pin 1
0.014 (0.35)
0.019 (0.49)
0.188 (4.78)
0.197 (5.00)
(4X) 7°
0.053 (1.35)
0.069 (1.75)
0.004 (0.19)
0.010 (0.25)
0.050 (1.27)
0.010 (0.25)
X 45°
0.020 (0.50)
0.050"Typical
0.050"
Typical
0° - 8°
0.0075 (0.19)
0.010 (0.25)
0.250"
0.016 (0.410)
0.037 (0.937)
FOOTPRINT
0.030"
Typical
8 Places
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
REV 1.7 7/10/03
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X9319
PACKAGING INFORMATION
8-Lead Plastic, DIP, Package Code P8
0.430 (10.92)
0.360 (9.14)
0.260 (6.60)
0.240 (6.10)
Pin 1 Index
Pin 1
0.060 (1.52)
0.020 (0.51)
0.300
(7.62) Ref.
Half Shoulder Width On
All End Pins Optional
0.145 (3.68)
0.128 (3.25)
Seating
Plane
0.025 (0.64)
0.015 (0.38)
0.065 (1.65)
0.045 (1.14)
0.150 (3.81)
0.125 (3.18)
0.110 (2.79)
0.090 (2.29)
.073 (1.84)
Max.
0.020 (0.51)
0.016 (0.41)
0.325 (8.25)
0.300 (7.62)
0°
15°
Typ. 0.010 (0.25)
NOTE:
1. ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
2. PACKAGE DIMENSIONS EXCLUDE MOLDING FLASH
LIMITED WARRANTY
©Xicor, Inc. 2003 Patents Pending
Devices sold by Xicor, Inc. are covered by the warranty and patent indemnification provisions appearing in its Terms of Sale only. Xicor, Inc. makes no warranty,
express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement.
Xicor, Inc. makes no warranty of merchantability or fitness for any purpose. Xicor, Inc. reserves the right to discontinue production and change specifications and prices
at any time and without notice.
Xicor, Inc. assumes no responsibility for the use of any circuitry other than circuitry embodied in a Xicor, Inc. product. No other circuits, patents, or licenses are implied.
TRADEMARK DISCLAIMER:
Xicor and the Xicor logo are registered trademarks of Xicor, Inc. AutoStore, Direct Write, Block Lock, SerialFlash, MPS, BiasLock and XDCP are also trademarks of
Xicor, Inc. All others belong to their respective owners.
U.S. PATENTS
Xicor products are covered by one or more of the following U.S. Patents: 4,326,134; 4,393,481; 4,404,475; 4,450,402; 4,486,769; 4,488,060; 4,520,461; 4,533,846;
4,599,706; 4,617,652; 4,668,932; 4,752,912; 4,829,482; 4,874,967; 4,883,976; 4,980,859; 5,012,132; 5,003,197; 5,023,694; 5,084,667; 5,153,880; 5,153,691;
5,161,137; 5,219,774; 5,270,927; 5,324,676; 5,434,396; 5,544,103; 5,587,573; 5,835,409; 5,977,585. Foreign patents and additional patents pending.
LIFE RELATED POLICY
In situations where semiconductor component failure may endanger life, system designers using this product should design the system with appropriate error detection
and correction, redundancy and back-up features to prevent such an occurrence.
Xicor’s products are not authorized for use in critical components in life support devices or systems.
1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to
perform, when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user.
2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life
support device or system, or to affect its safety or effectiveness.
REV 1.7 7/10/03
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Characteristics subject to change without notice.
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