APPLICATION NOTE
A V A I L A B L E
AN20 • AN42–53 • AN71 • AN73 • AN88 • AN91–92 • AN99 • AN115 • AN120 • AN124 • AN133 • AN134 • AN135
Terminal Voltages ±5V, 32 Taps
X9313
Digitally Controlled Potentiometer (XDCP™)
FEATURES
DESCRIPTION
• Solid-state potentiometer
• 3-wire serial interface
• 32 wiper tap points
—Wiper position stored in nonvolatile memory
and recalled on power-up
• 31 resistive elements
—Temperature compensated
—End to end resistance range ± 20%
—Terminal voltages, –5V to +5V
• Low power CMOS
—VCC = 3V or 5V
—Active current, 3mA max.
—Standby current, 500µA max.
• High reliability
—Endurance, 100,000 data changes per bit
—Register data retention, 100 years
• RTOTAL values = 1KΩ, 10KΩ, 50KΩ, 100KΩ
• Packages
—8-lead SOIC, MSOP and DIP
The Xicor X9313 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.
The potentiometer is implemented by a resistor array
composed of 31 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 or as a two-terminal variable resistor in
a wide variety of applications including:
– control
– parameter adjustments
– signal processing
BLOCK DIAGRAMS
U/D
INC
CS
VCC (Supply Voltage)
5-Bit
Up/Down
Counter
30
29
RH/VH
Up/Down
(U/D)
Control
and
Memory
Increment
(INC)
Device Select
(CS)
RH/VH
31
5-Bit
Nonvolatile
Memory
RW/VW
RL/VL
28
One
of
Thirty
Two
Decoder
Transfer
Gates
Resistor
Array
2
VSS (Ground)
General
VCC
VSS
Store and
Recall
Control
Circuitry
1
0
RL/VL
RW/VW
Detailed
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Characteristics subject to change without notice.
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X9313
PIN DESCRIPTIONS
PIN CONFIGURATION
RH/VH and RL/VL
The high (RH/VH) and low (RL/VL) terminals of the
X9313 are equivalent to the fixed terminals of a
mechanical potentiometer. The minimum voltage is
VSS and the maximum is VCC. The terminology of RL/
VL and RH/VH 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.
8-Lead DIP/SOIC
VCC
7
RH/VH
3
6
CS
RL/VL
VSS
4
5
RW/VW
X9313
RH/VH
1
VSS
2
RW/VW
3
RL/VL
4
X9313
Symbol
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 X9313
will be placed in the low power standby mode until the
device is selected once again.
This Material Copyrighted by Its Respective Manufacturer
8
2
8
U/D
7
INC
6
VCC
5
CS
PIN NAMES
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.
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1
U/D
8-Lead MSOP
RW/VW
RW/Vw 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 at VCC = 5V.
Up/Down (U/D)
The U/D input controls the direction of the wiper
movement and whether the counter is incremented or
decremented.
INC
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Description
RH/VH
High terminal
RW/VW
Wiper terminal
RL/VL
Low terminal
VSS
Ground
VCC
Supply voltage
U/D
Up/Down control input
INC
Increment control input
CS
Chip Select control input
Characteristics subject to change without notice.
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X9313
PRINCIPLES OF OPERATION
There are three sections of the X9313: the input
control, counter and decode section; the nonvolatile
memory; and the resistor array. The input 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. Under the proper conditions
the contents of the counter can be stored in nonvolatile
memory and retained for future use. The resistor array
is comprised of 31 individual resistors connected in
series. At either end of the array and between each
resistor is an electronic switch that transfers the
potential at that point to the wiper.
The wiper, when at either fixed terminal, acts like its
mechanical equivalent and does not move beyond the
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.
The system may select the X9313, 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 power-up/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.
MODE SELECTION
CS
INC
U/D
Mode
L
H
Wiper Up
L
L
Wiper Down
H
X
Store Wiper Position
X
X
Standby Current
L
X
No Store, Return to Standby
H
SYMBOL TABLE
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) a seven bit counter. The output of this
counter is decoded to select one of thirty two wiper
positions along the resistive array.
WAVEFORM
The value of the counter is stored in nonvolatile
memory whenever CS transitions HIGH while the INC
input is also HIGH.
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INPUTS
OUTPUTS
Must be
steady
Will be
steady
May change
from Low to
High
Will change
from Low to
High
May change
from High to
Low
Will change
from High to
Low
Don’t Care:
Changes
Allowed
N/A
Changing:
State Not
Known
Center Line
is High
Impedance
Characteristics subject to change without notice.
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X9313
ABSOLUTE MAXIMUM RATINGS
COMMENT
Temperature under bias ....................–65°C to +135°C
Storage temperature .........................–65°C to +150°C
Voltage on CS, INC, U/D, VH, VL and
VCC with respect to VSS ......................... –1V to +7V
∆V = |VH–VL|
X9313Z ................................................................... 4V
X9313W, X9313U, X9313T ................................... 10V
Lead temperature (soldering 10 seconds)..........300°C
IW (10 seconds) .............................................. ±8.8mA
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.
RECOMMENDED OPERATING CONDITIONS
Temperature
Min.
Max.
Supply Voltage (VCC)
Limits
Commercial
0°C
+70°C
X9313
5V ±10%
Industrial
–40°C
+85°C
X9313-3
3V to 5.5V
POTENTIOMETER CHARACTERISTICS (Over recommended operating conditions unless otherwise stated.)
Limits
Symbol
Parameter
Min.
Typ.
End to end resistance tolerance
Max.
Unit
±20
%
Test Conditions/Notes
VVH
VH terminal voltage
–5V
+5V
V
VVL
VL terminal voltage
–5V
+5V
V
Power rating
10
mW
RTOTAL ≥ 10 KΩ
Power rating
16
mW
RTOTAL = 1 KΩ
100
Ω
RW
Wiper resistance
IW
Wiper current
40
±4.4
Noise
Resolution
dBV
3
%
Absolute linearity
Relative
linearity(2)
RTOTAL temperature coefficient
MI(3)
Rw(n)(actual)–Rw(n)(expected)
±0.2
MI(3)
Rw(n+1)–[Rw(n)+MI]
ppm/°C
±20
10/10/25
Ref: 1kHz
±1
±300
Ratiometric temperature coefficient
CH/CL/CW Potentiometer capacitances
mA
-120
(1)
IW = 1mA, VCC = 5V
ppm/°C
pF;
See Circuit #3
Notes: (1) Absolute linearity is utilized to determine actual wiper voltage versus expected voltage = (Vw(n)(actual)–Vw(n)(expected)) = ±1 Ml
Maximum.
(2) Relative linearity is a measure of the error in step size between taps = RW(n+1)–[Rw(n) + Ml] = ±0.2 Ml.
(3) 1 Ml = Minimum Increment = RTOT/31.
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Characteristics subject to change without notice.
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X9313
D.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified.)
Limits
Symbol
Parameter
ICC
VCC active current
ISB
Standby supply current
Min.
Typ.(4)
Max.
Unit
1
3
mA
CS = VIL, U/D = VIL or VIH and
INC = 0.4V/2.4V @ max. tCYC
200
500
µA
CS = VCC – 0.3V, U/D and
INC = VSS or VCC – 0.3V
VIN = VSS to VCC
ILI
CS, INC, U/D input leakage current
±10
µA
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
Parameter
Min.
Unit
Minimum endurance
100,000
Data changes per bit per register
Data retention
100
Years
Notes: (4) Typical values are for TA = 25°C and nominal supply voltage.
(5) This parameter is periodically sampled and not 100% tested.
Test Circuit #1
Test Circuit #2
Circuit #3 SPICE Macro Model
RTOTAL
VH/RH
VH/RH
Test Point
RH
CH
VS
Test Point
VW/RW
VL/RL
VL/RL
A.C. CONDITIONS OF TEST
Input pulse levels
0V to 3V
Input rise and fall times
10ns
Input reference levels
1.5V
REV 1.1 10/23/00
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VW/RW
VW
Force
Current
CL
CW
RL
10pF
25pF
10pF
RW
A.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified)
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Characteristics subject to change without notice.
5 of 10
X9313
Limits
Symbol
Parameter
Typ.(6)
Min.
Max.
Unit
tCl
CS to INC setup
100
ns
tlD
INC HIGH to U/D change
100
ns
tDI
U/D to INC setup
2.9
µs
tlL
INC LOW period
1
µs
tlH
INC HIGH period
1
µs
tlC
INC Inactive to CS inactive
1
µs
tCPH
CS deselect time (STORE)
20
ms
tCPH
CS deselect time (NO STORE)
100
ns
tIW
tCYC
tR, tF(7)
tPU(7)
tR VCC(7)
tWR
INC to Vw change
1
INC cycle time
5
µs
4
µs
INC input rise and fall time
Power up to wiper stable
VCC power-up rate
0.2
Store cycle
5
500
µs
5
µs
50
V/ms
10
ms
POWER UP AND DOWN REQUIREMENTS
There are no restrictions on the sequencing of VCC and the voltages applied to the potentiometer pins during
power-up or power-down conditions. During power-up, the data sheet parameters for the DCP do not fully apply
until 1 millisecond after VCC reaches is final value. The VCC ramp spec is always in effect.
A.C. TIMING
CS
tCYC
tCI
tIL
tIH
tIC
tCPH
90% 90%
10%
INC
tID
tDI
tF
tR
U/D
tIW
VW
MI
(8)
Notes: (6) Typical values are for TA = 25°C and nominal supply voltage.
(7) This parameter is not 100% tested.
(8) MI in the A.C. timing diagram refers to the minimum incremental change in the VW output due to a change in the wiper position.
REV 1.1 10/23/00
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Characteristics subject to change without notice.
6 of 10
X9313
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
VR
VR
VH
VW/RW
VL
I
Three terminal potentiometer;
variable voltage divider
Two terminal variable resistor;
variable current
Basic Circuits
Buffered Reference Voltage
Noninverting Amplifier
Cascading Techniques
R1
+V
+5V
+V
+V
VS
+5V
VW
VREF
+
VO
–
OP-07
VOUT
–
LM308A
+
–5V
X
VW/RW
R2
+V
–5V
R1
VW
VOUT = VW/RW
(a)
Voltage Regulator
VIN
(b)
VO = (1+R2/R1)VS
Offset Voltage Adjustment
VO (REG)
317
R1
Comparator with Hysteresis
R2
VS
VS
R1
LT311A
100KΩ
+
–
10KΩ
10KΩ
VO (REG) = 1.25V (1+R2/R1)+Iadj R2
+12V
}
10KΩ
}
TL072
R2
VO
VO
+
Iadj
–
R1
R2
VUL = {R1/(R1+R2)} VO(max)
VLL = {R1/(R1+R2)} VO(min)
-12V
(for additional circuits see AN115)
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Characteristics subject to change without notice.
7 of 10
X9313
PACKAGING INFORMATION
8-Lead Miniature Small Outline Gull Wing Package Type M
0.118 ± 0.002
(3.00 ± 0.05)
0.012 + 0.006 / -0.002
(0.30 + 0.15 / -0.05)
0.0256 (0.65) Typ.
R 0.014 (0.36)
0.118 ± 0.002
(3.00 ± 0.05)
0.030 (0.76)
0.0216 (0.55)
0.036 (0.91)
0.032 (0.81)
0.040 ± 0.002
(1.02 ± 0.05)
7° Typ.
0.008 (0.20)
0.004 (0.10)
0.0256" Typical
0.007 (0.18)
0.005 (0.13)
0.025"
Typical
0.150 (3.81)
Ref.
0.193 (4.90)
Ref.
0.220"
FOOTPRINT
0.020"
Typical
8 Places
NOTE:
1. ALL DIMENSIONS IN INCHES AND (MILLIMETERS)
REV 1.1 10/23/00
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Characteristics subject to change without notice.
8 of 10
X9313
PACKAGING INFORMATION
8-Lead Plastic Small Outline Gull Wing Package Type S
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)
0.030"
Typical
8 Places
FOOTPRINT
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
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Characteristics subject to change without notice.
9 of 10
X9313
ORDERING INFORMATION
X9313X
X
X
X
VCC Limits
Blank = 4.5V to 5.5V
3 = 3V to 5.5V
Temperature Range
Blank = Commercial = 0°C to +70°C
I = Industrial = –40°C to +85°C
Package
M = 8-Lead MSOP
P = 8-Lead Plastic DIP
S = 8-Lead SOIC
End to End Resistance
Z=
1KΩ
W=
10KΩ
U=
50KΩ
T=
100KΩ
Physical Characteristics
Marking Includes
Manufacturer’s Trademark
Resistance Value or Code
Date Code
LIMITED WARRANTY
©Xicor, Inc. 2000 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, 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.
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Characteristics subject to change without notice.
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