APPLICATION NOTE
A V A I L A B L E
AN99 • AN115 • AN120 • AN124 • AN133 • AN134
Low Noise, Low Power, Low Cost
X9116
Digitally Controlled Potentiometer (XDCP™)
FEATURES
DESCRIPTION
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The Xicor X9116 is a digitally controlled nonvolatile
potentiometer designed to be used in trimmer applications. The pot consists of 15 equal resistor segments
that connect to the wiper pin through programmable
CMOS switches. The tap position is programmed
through a 3-wire up/down serial port. The last position
of the wiper is stored in a nonvolatile memory location
which is recalled at the time of power up of the device.
Solid-state nonvolatile
16 wiper taps
3-wire up/down serial interface
VCC = 2.7V and 5V
Active current < 50µA max.
Standby current < 1µA max.
RTOTAL = 10KΩ
Packages: MSOP-8, SOIC
The wiper moves through sequential tap positions with
inputs on the serial port. A falling edge on INC (bar)
causes the tap position to increment one position up or
down based on whether the U/D (bar) pin is held high
or low.
The X9116 can be used in many applications requiring
a variable resistance. In many cases it can replace a
mechanical trimmer and offers many advantages such
as temperature and time stability as well as the reliability of a solid state solution.
BLOCK DIAGRAM
VCC (Supply Voltage)
RH/VH
Up/Down
(U/D)
Increment
(INC)
Control
and
Memory
Device Select
(CS)
RW/VW
RL/VL
VSS (Ground)
RW-RL Resistance
General
15
RH
14
13
*
3
2
1
RL
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0
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10kΩ
9.34kΩ
8.68kΩ
* kΩ
2.08kΩ
1.42kΩ
760Ω
100Ω
Characteristics subject to change without notice.
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X9116
PIN DESCRIPTIONS
PIN NAMES
VH /RH and VL /RL
The high (VH/RH) and low (VL/RL) terminals of the
X9116 are equivalent to the fixed terminals of a
mechanical potentiometer. The minimum voltage is
VSS and the maximum is VCC.
Symbol
VSS
Ground
VW/RW
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 200Ω to 400Ω depending upon VCC.
VCC
Supply Voltage
U/D
Up/Down Control Input
INC
Increment Control Input
CS
Chip Select Input
Up/Down (U/D)
The U/D input controls the direction of the wiper movement and whether the counter is incremented (up) or
decremented (down).
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 X9116
will be placed in the low power standby mode until the
device is selected once again.
PIN CONFIGURATION
SOIC/MSOP
INC
1
U/D
2
VH/RH
3
VSS
4
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X9116
8
VCC
7
CS
6
VL/RL
5
VW/RW
Description
VH/RH
High Terminal
VW/RW
Wiper Terminal
VL/RL
Low Terminal
PRINCIPLES OF OPERATION
There are three sections of the X9116: 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 15 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 pin.
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.
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Characteristics subject to change without notice.
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X9116
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) a four bit counter. The output of this
counter is decoded to select one of 16 wiper positions
along the resistive array.
The value of the counter is stored in nonvolatile memory whenever CS transitions HIGH while the INC input
is also HIGH.
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
WAVEFORM
The system may select the X9116, 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 recalls 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.
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
Changing:
State Not
Known
N/A
Center Line
is High
Impedance
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.
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Characteristics subject to change without notice.
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X9116
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/RH, VL/RL
and VCC with respect to VSS ................... –1V to +7V
∆V = |VH/RH–VL/RL| ............................................ 5.5V
Lead temperature (soldering 10 seconds)..........300°C
IW (10 seconds) ............................................ ±10.0mA
Stresses above those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device.
This is a stress rating only; the 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
X9116
5V ±10%
Industrial
–40°C
+85°C
X9116-2.7
2.7V to 5.5V
POTENTIOMETER CHARACTERISTICS (Over recommended operating conditions unless otherwise stated)
Limits
Symbol
RTOTAL
Parameter
Min.
Typ.
Max.
Unit
Test Conditions/Notes
End to end resistance variation
–20
+20
%
VVH
VH/RH terminal voltage
VSS
VCC
V
VSS = 0V
VVL
VL/RL terminal voltage
VSS
VCC
V
VSS = 0V
10
mW
Power rating
RTOTAL = 10 KΩ
RW
Wiper resistance
200
400
Ω
IW = 1mA, VCC = 5V
RW
Wiper resistance
400
1000
Ω
IW = 1mA, VCC = 2.7V
IW
Wiper current
+5.0
mA
-5.0
Noise
-120
Resolution
dBV√Hz Ref: 1kHz
6
(1)
%
Absolute linearity
-1
+1
MI(3)
Vw(n)(actual)–Vw(n)(expected)
Relative linearity(2)
-0.2
+0.2
MI(3)
Vw(n+1)–[Vw(n)+MI]
RTOTAL temperature coefficient
±300
Ratiometric temperature coefficient
CH/CL/CW Potentiometer capacitances
ppm/°C
±20
10/10/25
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 = VW(n+1)–[Vw(n) + Ml] = ±0.2 Ml.
(3) 1 Ml = Minimum Increment = RTOT/15.
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Characteristics subject to change without notice.
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X9116
D.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified)
Limits
Symbol
Parameter
Typ.(4)
Min.
Max.
Unit
Test Conditions
ICC1
VCC active current (Increment)
150
µA
CS = VIL, U/D = VIL or VIH and
INC = 0.4V/2.4V @ max. tCYC
ICC2
VCC active current (Store)
(EEPROM Store)
400
µA
CS = VIH, U/D = VIL or VIH and
INC = VIH @ max. tWR
ISB
Standby supply current
1
µA
CS = VCC–0.3V, U/D and
INC = VSS or VCC–0.3V
ILI
CS, INC, U/D input leakage
current
±10
µA
VIN = VSS to VCC
VIH
CS, INC, U/D input HIGH voltage
2V
VCC + 0.5
V
VIL
CS, INC, U/D input LOW voltage
–0.5
0.8
V
CIN(5)
CS, INC, U/D input capacitance
10
pF
VCC = 5V, VIN = VSS,
TA = 25°C, f = 1MHz
Notes: (4) Typical values are for TA = 25°C and nominal supply voltage.
(5) This parameter is periodically sampled and not 100% tested.
ENDURANCE AND DATA RETENTION
Parameter
Min.
Unit
Minimum endurance
100,000
Data changes per bit
Data retention
100
Years
Test Circuit #1
Test Circuit #2
Circuit #3 SPICE Macro Model
VH/RH
VH/RH
RTOTAL
RH
VS
Test Point
VW/RW
Test Point
VWVW
/RW
VLL/RL
VL/RL
Force
Current
CW
CH
RL
CL
10pF
25pF
10pF
RW
A.C. CONDITIONS OF TEST
Input pulse levels
0V to 3V
Input rise and fall times
10ns
Input reference levels
1.5V
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Characteristics subject to change without notice.
5 of 11
X9116
A.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified)
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)
10
ms
INC to Vw change
tIW
tCYC
tR, tF(7)
tPU(7)
tR VCC(7)
tWR
1
INC cycle time
5
µs
4
µs
INC input rise and fall time
Power up to wiper stable
VCC Power-up rate
15
Store cycle
5
500
µs
5
µs
50
mV/µs
10
ms
POWER UP AND DOWN REQUIREMENTS
There are no restrictions on the power-up or power-down conditions of VCC and the voltages applied to the potentiometer pins provided that VCC is always more positive than or equal to VH, VL, and VW, i.e., VCC ≥ VH, VL, VW. The
VCC ramp rate spec is always in effect.
A.C. TIMING
CS
tCYC
tCI
tIL
(store)
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 1.2 2/5/03
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Characteristics subject to change without notice.
6 of 11
X9116
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
VREF
VW
VOUT
–
VO
–
OP-07
+
LM308A
+
–5V
X
VW/RW
R2
+V
–5V
R1
VW
VOUT = VW/RW
(a)
Voltage Regulator
VIN
(b)
VO = (1+R2/R1)VS
Comparator with Hysteresis
VO (REG)
317
VS
LT311A
R1
–
+
VO
Iadj
}
}
R2
R1
R2
VUL = {R1/(R1+R2)} VO(max)
VLL = {R1/(R1+R2)} VO(min)
VO (REG) = 1.25V (1+R2/R1)+Iadj R2
(for additional circuits see AN115)
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Characteristics subject to change without notice.
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X9116
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 1.2 2/5/03
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Characteristics subject to change without notice.
8 of 11
X9116
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 1.2 2/5/03
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Characteristics subject to change without notice.
9 of 11
X9116
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)
REV 1.2 2/5/03
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X9116
Ordering Information
X9116X
X
X
X
VCC Limits
Blank = 5V ±10%
–2.7 = 2.7V to 5.5V
Temperature Range
Blank = Commercial = 0°C to +70°C
I = Industrial = –40°C to +85°C
Package
M8 = 8-Lead MSOP
S8 = 8-Lead SOIC
End to End Resistance
W=
10KΩ
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.
REV 1.2 2/5/03
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Characteristics subject to change without notice.
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