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
Low Noise, Low Power, 100 Taps
X9317
Digitally Controlled Potentiometer (XDCP™)
FEATURES
DESCRIPTION
•
•
•
•
•
•
•
•
•
•
•
The Xicor X9317 is a nonvolatile digitally controlled
potentiometer (XDCP). The device consists of a polycrystalline resistor array of 99 segments and CMOS
switches that connect the wiper terminal to any one of
the 100 nodes in the array of resistors. The wiper position is defined by the data that is transmitted to the
device on the 3 terminal serial Up/Down port. A pulse
on the increment pin causes the wiper to move one
step to the next wiper position. The direction the wiper
moves is defined by the logic state on the Up/Down
pin. A rising edge on the Chip Select pin while the
increment pin is high causes the present wiper position to be written into an EPROM register. This value is
recalled on power up restoring the last wiper position
that was written into the register.
Nonvolatile solid state potentiometer
Single device
100 resistor taps
3-wire serial up/down interface
Wiper resistance 200Ω typ. at 5V
RTOTAL values = 1kΩ, 10kΩ, 50kΩ, 100kΩ
Standby current < 1µA
VCC = 5V and 2.7V to 5.5V
Endurance = 100,000 cycles
Data retention = 100 years
Packages – 8-lead DIP, SOIC, TSSOP, MSOP
The device can be used in the two terminal mode, with
the wiper connected to one end of the total resistor, as
a variable resistor or can be used in the three terminal
mode as a programmable voltage reference. The
X9317 can be used to program offset voltages or set
gains on amplifiers in control circuits.
BLOCK DIAGRAM
U/D
INC
CS
VCC (Supply Voltage)
7-Bit
Up/Down
Counter
Control
and
Memory
98
97
RH/VH
Up/Down
(U/D)
Increment
(INC)
Device Select
(CS)
RH/VH
99
7-Bit
Nonvolatile
Memory
RW/VW
RL/VL
96
One
of
One
Hundred
Decoder
Transfer
Gates
Resistor
Array
2
VSS (Ground)
General
VCC
VSS
Store and
Recall
Control
Circuitry
1
0
RL/VL
RW/VW
Detailed
REV 1.1.4 12/09/02
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Characteristics subject to change without notice.
1 of 14
X9317
PIN DESCRIPTIONS
PIN CONFIGURATION
RH/VH and RL/VL
The high (RH/VH) and low (RL/VL) terminals of the
X9317 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.
TSSOP
1
8
RL/VL
2
7
RW/VW
INC
3
6
U/D
4
VSS
RH/VH
INC
1
U/D
2
RH/VH
3
VSS
4
5
X9317
8
VCC
7
CS
6
RL/VL
5
RW/VW
PIN NAMES
Symbol
RH/VH
High Terminal
Wiper Terminal
RL/VL
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 X9317
will be placed in the low power standby mode until the
device is selected once again.
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Description
RW/VW
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.
REV 1.1.4 12/09/02
X9317
DIP/SOIC/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 200Ω when 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.
CS
VCC
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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X9317
PRINCIPLES OF OPERATION
There are three sections of the X9317: 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 99 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 X9317, 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
will would 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 one hundred 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.
REV 1.1.4 12/09/02
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WAVEFORM
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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X9317
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|........................................................... 5V
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 and 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
X9317
5V ±10%
Industrial
–40°C
+85°C
X9317-2.7
2.7V to 5.5V
POTENTIOMETER CHARACTERISTICS (Over recommended operating conditions unless otherwise stated.)
Limits
Symbol
Parameter
Min.
Typ.
Max.
Unit
±20
%
Test Conditions/Notes
RTOTAL
End to End Resistance Variation
VVH/RH
VH Terminal Voltage
VSS
VCC
V
VSS = 0V
VVL/RL
VL Terminal Voltage
VSS
VCC
V
VSS = 0V
Power Rating
10
mW
RTOTAL ≥ 10 KΩ
Power Rating
25
mW
RTOTAL = 1 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
±4.4
mA
Noise
Resolution
-120
dBV
1
%
(1)
Absolute Linearity
Relative
Linearity(2)
RTOTAL Temperature Coefficient
Potentiometer Capacitances
±1
MI(3)
Vw(n)(actual)–Vw(n)(expected)
±.2
MI(3)
Vw(n+1)–[Vw(n)+MI]
±300
Ratiometric Temperature Coefficient
CH/CL/CW
ppm/°C
±20
10/10/
25
Ref: 1kHz
ppm/°C
pF
See circuit #3
Notes: (1) Absolute Linearity is utilized to determine actual wiper voltage versus expected voltage = (V w(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/99.
(4) Typical values are for TA = 25°C and nominal supply voltage.
(5) This parameter is periodically sampled and not 100% tested.
REV 1.1.4 12/09/02
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Characteristics subject to change without notice.
4 of 14
X9317
D.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified.)
Limits
Symbol
Parameter
Min.
Typ.(4)
Max.
Unit
Test Conditions
ICC1
VCC Active Current
(Increment)
50
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
±10
µA
VIN = VSS to VCC
VCC x 0.7
VCC + 0.5
V
–0.5
VCC x 0.1
V
10
pF
Leakage Current
VIH
CS, INC, U/D Input
HIGH Voltage
VIL
CS, INC, U/D Input
LOW Voltage
CIN(5)
CS, INC, U/D Input
VCC = 5V, VIN = VSS,
Capacitance
TA = 25°C, f = 1MHz
ENDURANCE AND DATA RETENTION
Parameter
Min.
Unit
Minimum endurance
100,000
Data changes per bit per bit
Data retention
100
Years
Test Circuit #1
Circuit #3 SPICE Macro Model
Test Circuit #2
VH/RH
VH
RTOTAL
Test Point
VS
REV 1.1.4 12/09/02
CW
CH
Test Point
VW/RW
VL/RL
RH
VW
VL
Force
Current
www.xicor.com
RL
CL
10pF
25pF
10pF
RW
Characteristics subject to change without notice.
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X9317
A.C. CONDITIONS OF TEST
Input pulse levels
0V to 3V
Input rise and fall times
10ns
Input reference levels
1.5V
A.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified)
Limits
Symbol
Parameter
Typ.(6)
Min.
Max.
Units
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
ns
tCPH
CS Deselect Time (NO STORE)
100
tCPH
CS Deselect Time (STORE)
10
tIW
tCYC
tR, tF(7)
tPU(7)
tR VCC(7)
tWR
ms
INC to VW Change
1
INC Cycle Time
5
µs
500
µs
5
µs
50
V/ms
10
ms
4
µs
INC Input Rise and Fall Time
Power up to Wiper Stable
VCC Power-up Rate
0.2
Store Cycle
5
A.C. TIMING
CS
tCYC
tCI
tIL
(store)
tCPH
tIC
tIH
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 periodically sampled and 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 1.1.4 12/09/02
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Characteristics subject to change without notice.
6 of 14
X9317
PERFORMANCE CHARACTERISTICS (TYPICAL)
Typical Total Resistance Temperature Coefficient
0
-50
-100
-150
PPM
-200
-250
-300
-350
-55
-45
-35
-25
-15
-5
5
15
25
35
45
55
65
75
85
95
105
115
125
Temperature (°C)
REV 1.1.4 12/09/02
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Characteristics subject to change without notice.
7 of 14
X9317
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/RH
VW/RW
VL/RL
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
VS
+V
+5V
VW
VREF
+
VOUT
–5V
X
VW/RW
R2
+V
–5V
R1
VW/RW
VOUT = VW/RW
(a)
Voltage Regulator
(b)
VO = (1+R2/R1)VS
Comparator with Hysteresis
Offset Voltage Adjustment
VO (REG)
317
VO
–
OP-07
–
VIN
LM308A
+
R1
R2
VS
VS
R1
LT311A
–
+
VO
100KΩ
–
VO
+
10KΩ
10KΩ
10KΩ
}
TL072
R2
}
Iadj
R1
R2
VUL = {R1/(R1+R2)} VO(max)
VLL = {R1/(R1+R2)} VO(min)
VO (REG) = 1.25V (1+R2/R1)+Iadj R2
+12V
REV 1.1.4 12/09/02
-12V
www.xicor.com
(for additional circuits see AN115)
Characteristics subject to change without notice.
8 of 14
X9317
PACKAGING INFORMATION
8-Lead Plastic Dual In-Line Package Type P
0.430 (10.92)
0.360 (9.14)
0.260 (6.60)
0.240 (6.10)
Pin 1 Index
Pin 1
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.
0.060 (1.52)
0.020 (0.51)
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
REV 1.1.4 12/09/02
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Characteristics subject to change without notice.
9 of 14
X9317
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 1.1.4 12/09/02
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Characteristics subject to change without notice.
10 of 14
X9317
PACKAGING INFORMATION
8-Lead Plastic, TSSOP, Package Type V
.025 (.65) BSC
.169 (4.3)
.252 (6.4) BSC
.177 (4.5)
.114 (2.9)
.122 (3.1)
.047 (1.20)
.0075 (.19)
.0118 (.30)
.002 (.05)
.006 (.15)
.010 (.25)
Gage Plane
0° – 8°
Seating Plane
.019 (.50)
.029 (.75)
(4.16) (7.72)
Detail A (20X)
(1.78)
.031 (.80)
.041 (1.05)
(0.42)
(0.65)
All Measurements Are Typical
See Detail “A”
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
REV 1.1.4 12/09/02
www.xicor.com
Characteristics subject to change without notice.
11 of 14
X9317
PACKAGING INFORMATION
M Package
8-Lead Miniature Small Outline Gull Wing Package Type MSOP
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 1.1.4 12/09/02
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Characteristics subject to change without notice.
12 of 14
X9317
ORDERING INFORMATION
X9317X
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
P = 8-Lead Plastic Dip
S8 = 8-Lead SOIC
V8 = 8-Lead TSSOP
M8 = 8-Lead MSOP
End to End Resistance
W =10KΩ
U = 50KΩ
Z = 1KΩ
T = 100KΩ
Physical Characteristics
Marking Includes
Manufacturer’s Trademark
Resistance Value or Code
Date Code
REV 1.1.4 12/09/02
MSOP Part No.
Mark
X9317WM8
ABF
X9317WM8-2.7
ACZ
X9317WM8I
ADS
X9317WM8I-2.7
ADT
X9317UM8
AEC
X9317UM8-2.7
AED
X9317UM8I
AFE
X9317UM8I-2.7
AFF
X9317ZM8
AFG
X9317ZM8-2.7
AFH
X9317ZM8I
AFI
X9317ZM8I-2.7
AFJ
X9317TM8
AGD
X9317TM8-2.7
AGE
X9317TM8I
AGF
X9317TM8I-2.7
AGG
X9317TV8
9317T
X9317TV8-2.7
317TF
X9317TV8I
317TI
X9317TV8I-2.7
317TG
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Characteristics subject to change without notice.
13 of 14
X9317
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 1.1.4 12/09/02
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Characteristics subject to change without notice.
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