9900-2009.3 9/20/99 PS
1
Characteristics subject to change without notice
Low Noise, Low Power
X9015
Digitally-Controlled Potentiometer
FEATURES
32 Taps
Three-wire Up/Down Serial Interface
V
CC
= 2.7V & 5V
Operating I
CC
= 50A Max.
Standby current = 1A Max.
R
TOTAL
= 50K
Packages, SOIC-8
DESCRIPTION
The Xicor X9015 is a 32 tap potentiometer that is volatile.
The device consists of a string of 31 resistors that can be
programmed to connect the R
W
/V
W
wiper output with
any of the nodes between the connecting resistors. The
connection point of the wiper is determined by
information communicated to the device on the 3-wire
port. The 3-wire port changes the tap position by a falling
edge on the increment pin. Direction the wiper moves is
determined by the state of the Up/Down pin. The wiper
position at power up is tap #15.
The X9015 can be used in a wide variety of applications
that require a digitally controlled variable resistor to set
analog values.
FUNCTIONAL DIAGRAMS
5-BIT
UP/DOWN
COUNTER
CONTROL
CIRCUITRY
ONE
OF
DECODER
RESISTOR
ARRAY
R
H
/V
H
U/D
INC
CS
TRANSFER
GATES
THIRTY TWO
V
CC
V
SS
R
L
/V
L
R
W
/V
W
CONTROL
UP/DOWN
(U/D)
INCREMENT
(INC)
DEVICE SELECT
(CS)
V
CC
(Supply Voltage)
V
SS
(Ground)
R
H
/V
H
R
W
/V
W
R
L
/V
L
GENERAL
DETAILED
0
1
2
28
29
30
31
X9015
2
PIN DESCRIPTIONS
R
H
/V
H
and R
L
/V
L
The high (R
H
/V
H
) and low (R
L
/V
L
) terminals of the
X9015 are equivalent to the fixed terminals of a
mechanical potentiometer. The minimum voltage is V
SS
and the maximum is V
CC
. The terminology of R
L
/V
L
and
R
H
/V
H
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.
R
W
/V
W
R
W
/V
w
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 200
at V
CC
= 5V. At power up the wiper
position is at tap #15 (V
L
/R
L
= tap #0).
Up/Down (U/D)
The U/D input controls the direction of the wiper
movement and whether the tap postion 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. When
CS is returned HIGH while the INC input is LOW the
X9015 will be placed in the low power standby mode until
the device is selected once again.
PIN CONFIGURATION
PIN NAMES
Symbol
Description
R
H
/V
H
High Terminal
R
W
/V
W
Wiper Terminal
R
L
/V
L
Low Terminal
V
SS
Ground
V
CC
Supply Voltage
U/D
Up/Down Control Input
INC
Increment Control Input
CS
Chip Select Control Input
V
CC
CS
INC
U/D
R
H
/V
H
V
SS
1
2
3
4
8
7
6
5
X9015
SOIC
R
L
/V
L
R
W
/V
W
X9015
3
PRINCIPLES OF OPERATION
There are two sections of the X9015: the input control,
counter and decode section; 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 resis-
tor array to the wiper output. The resistor array is com-
prised of 31 individual resistors connected in series.
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 t
IW
(INC to V
W
change). The R
TOTAL
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 wiper position is
lost. When power is restored, the wiper is set to tap #15.
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 five bit counter. The output of this counter is
decoded to select one of thirty two wiper positions along
the resistive array.
The system may select the X9015, move the wiper and
deselect the device. The new wiper position will be
maintained until changed by the system or until a power-
up/down cycle.
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
SYMBOL TABLE
CS
INC
U/D
Mode
L
H
Wiper Up
L
L
Wiper Down
H
X
X
Standby Current
L
X
Return to standby
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
Changing:
State Not
Known
N/A
Center Line
is High
Impedance
X9015
4
ABSOLUTE MAXIMUM RATINGS*
Temperature under Bias .........................65
C to +135
C
Storage Temperature..............................65C to +150C
Voltage on CS, INC, U/D, V
H
, V
L
and V
CC
with Respect to V
SS
.................................. 1V to +7V
V = |V
H
V
L
| ................................................................. 5V
Lead Temperature (Soldering 10 seconds)............. 300C
*COMMENT
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 condi-
tions for extended periods may affect device reliability.
RECOMMENDED OPERATING CONDITIONS
Temperature
Min.
Max.
Commercial
0C
+70C
Industrial
40C
+85C
Supply Voltage (V
CC
)
Limits
X9015
5V 10%
X9015-2.7
2.7V to 5.5V
POTENTIOMETER CHARACTERISTICS (Over recommended operating conditions unless otherwise stated.)
Notes:
(1) Absolute Linearity is utilized to determine actual wiper voltage versus expected voltage
= (V
w(n)
(actual) V
w(n)
(expected)) = 1 Ml Maximum.
(2) Relative Linearity is a measure of the error in step size between taps = V
W(n+1)
[V
w(n)
+ Ml] = 0.2 Ml.
(3) 1 Ml = Minimum Increment = R
TOT
/31.
(4) Typical values are for T
A
= 25C and nominal supply voltage.
(5) This parameter is periodically sampled and not 100% tested.
Symbol
Parameter
Limits
Test Conditions/Notes
Min.
Typ.
Max.
Units
R
TOTAL
End to End Resistance Variation
20
+20
%
V
VH
V
H
Terminal Voltage
0
V
CC
V
V
VL
V
L
Terminal Voltage
0
V
CC
V
Power Rating
10
mW
R
TOTAL
50K
R
W
Wiper Resistance
200
400
I
W
= 1mA, V
CC
= 5V
R
W
Wiper Resistance
400
1000
I
W
= 1mA, V
CC
= 2.7V
I
W
Wiper Current
1
mA
Noise
-120
dBV
Ref: 1kHz
Resolution
3
%
Absolute Linearity
(1)
-1
+1
MI
(3)
V
w(n)(actual)
V
w(n)(expected)
Relative Linearity
(2)
-0.2
+0.2
MI
(3)
V
w(n+1)
[V
w(n)+MI
]
R
TOTAL
Temperature Coefficient
300
ppm/C
Ratiometric Temperature Coefficient
20
ppm/C
C
H
/C
L
/C
W
Potentiometer Capacitances
10/10/25
pF
See circuit #3
X9015
5
D.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified.)
Symbol
Parameter
Limits
Units
Test Conditions
Min.
Typ.
(4)
Max.
I
CC1
V
CC
Active Current
(Increment)
50
A
CS = V
IL
, U/D = V
IL
or V
IH
and
INC = 0.4V @ max. t
CYC
I
SB
Standby Supply Current
1
A
CS = V
CC
0.3V, U/D and
INC = V
SS
or V
CC
0.3V
I
LI
CS, INC, U/D Input
10
A
V
IN
= V
SS
to V
CC
Leakage Current
V
IH
CS, INC, U/D Input
V
CC
x 0.7
V
CC
+ 0.5
V
HIGH Voltage
V
IL
CS, INC, U/D Input
0.5
V
CC
x 0.1
V
LOW Voltage
C
IN
(5)
CS, INC, U/D Input
10
pF
V
CC
= 5V, V
IN
= V
SS
,
Capacitance
T
A
= 25C, f = 1MHz
Test Circuit #2
FORCE
CURRENT
V
L
VW
V
H
TEST POINT
Test Circuit #1
TEST POINT
V
W
/R
W
V
H
/R
H
V
L
/R
L
V
S
Test Circuit #2
FORCE
CURRENT
V
L
VW
V
H
TEST POINT
Test Circuit #2
FORCE
CURRENT
V
L
VW
POINT
V
H
/R
H
V
W
/R
W
V
L
/R
L
Circuit #3 SPICE Macromodel
C
H
C
L
R
W
10pF
10pF
R
H
R
L
R
TOTAL
C
W
25pF
X9015
6
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)
A.C. TIMING
Notes: (6) Typical values are for T
A
= 25C 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 V
W
output due to a change in the wiper position.
Symbol
Parameter
Limits
Units
Min.
Typ.
(6)
Max.
t
Cl
CS to INC Setup
100
ns
t
lD
INC HIGH to U/D Change
100
ns
t
DI
U/D to INC Setup
2.9
s
t
lL
INC LOW Period
1
s
t
lH
INC HIGH Period
1
s
t
lC
INC Inactive to CS Inactive
1
s
t
CPH
CS Deselect Time
100
ns
t
IW
INC to Vw Change
1
5
s
t
CYC
INC Cycle Time
4
s
t
R,
t
F
(7)
INC Input Rise and Fall Time
500
s
t
PU
(7)
Power up to Wiper Stable
5
s
t
R
V
CC
(7)
V
CC
Power-up Rate
0.2
50
V/ms
CS
INC
U/D
V
W
t
CI
t
IL
t
IH
t
CYC
t
ID
t
DI
t
IW
MI
(8)
t
CPH
t
F
t
R
10%
90%
90%
(Stand by)
t
IC
X9015
7
PERFORMANCE CHARACTERISTICS (TYPICAL)
TYPICAL NOISE
TYPICAL RTOTAL vs. TEMPERATURE
TYPICAL TOTAL RESISTANCE TEMPERATURE COEFFICIENT
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
-140
-150
0
10
20
30
40
50
60
70
80
90
100
Frequency (KHz)
Noise (dB)
110
120
130
140
150
160
170
180
190
200
10000
9800
9600
9400
9200
9000
8800
8600
8400
8200
8000
Rtotal
-55
-45
-35
-25
-15
-5
5
15
25
35
45
55
65
75
Temperature
85
95
105
115 125 C
-55
-350
-300
-250
-200
-150
-100
-50
0
-45
-35
-25
-15
-5
5
15
25
35
Temperature
PPM
45
55
65
75
85
95
105
115
125
C
X9015
8
TYPICAL WIPER RESISTANCE
TYPICAL ABSOLUTE % ERROR PER TAP POSITION
TYPICAL RELATIVE % ERROR PER TAP POSITION
0
0
100
200
300
400
Rw (Ohms)
500
600
700
800
2
4
6
8
10
12
14
16
Tap
18
20
22
24
26
28
30
32
V
CC
= 2.7V
40.0%
30.0%
20.0%
10.0%
0.0%
-10.0%
-20.0%
-30.0%
-40.0%
0
3
6
9
12
15
Tap
Absolute % Error
18
21
24
27
30
20.0%
15.0%
10.0%
5.0%
0.0%
-5.0%
-10.0%
-15.0%
-20.0%
0
3
6
9
12
15
Tap
Relative % Error
18
21
24
27
30
X9015
9
APPLICATIONS INFORMATION
Electronic digitally-controlled (XDCP) potentiometers provide two powerful application advantages; (1) the variability and
reliability of a solid-state potentiometer, and (2) the flexibility of computer-based digital controls.
Basic Configurations of Electronic Potentiometers
Basic Circuits
V
R
V
W
V
R
I
Three terminal potentiometer;
variable voltage divider
Two terminal variable resistor;
variable current
V
H
V
L
Cascading Techniques
Buffered Reference Voltage
+
+5V
R
1
+V
5V
V
W
V
REF
V
OUT
OP-07
V
W
V
W
+V
+V
+V
X
(a)
(b)
V
OUT
= V
W
Noninverting Amplifier
+
V
S
V
O
R
2
R
1
V
O
= (1+R
2
/R
1
)V
S
LM308A
Voltage Regulator
R
1
R
2
I
adj
V
O
(REG) = 1.25V (1+R
2
/R
1
)+I
adj
R
2
V
O
(REG)
V
IN
317
Offset Voltage Adjustment
+
V
S
V
O
R
2
R
1
100K
10K
10K
10K
-12V
+12V
TL072
Comparator with Hysterisis
V
UL
= {R
1
/(R
1
+R
2
)} V
O
(max)
V
LL
= {R
1
/(R
1
+R
2
)} V
O
(min)
+
V
S
V
O
R
2
R
1
}
}
LT311A
+5V
5V
(for additional circuits see AN115)
X9015
10
SOIC PACKAGING INFORMATION
0.150 (3.80)
0.158 (4.00)
0.228 (5.80)
0.244 (6.20)
0.014 (0.35)
0.019 (0.49)
PIN 1
PIN 1 INDEX
0.010 (0.25)
0.020 (0.50)
0.050 (1.27)
0.188 (4.78)
0.197 (5.00)
0.004 (0.19)
0.010 (0.25)
0.053 (1.35)
0.069 (1.75)
(4X) 7
0.016 (0.410)
0.037 (0.937)
0.0075 (0.19)
0.010 (0.25)
0
8
X 45
8-LEAD PLASTIC SMALL OUTLINE GULL WING PACKAGE TYPE S
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
0.250"
0.050" TYPICAL
0.050"
TYPICAL
0.030"
TYPICAL
8 PLACES
FOOTPRINT
X9015
11
X
ORDERING INFORMATION
LIMITED WARRANTY
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,
licenses are implied.
U.S. PATENTS
Xicor products are covered by one or more of the following U.S. Patents: 4,263,664; 4,274,012; 4,300,212; 4,314,265; 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. 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 occurence.
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.
V
CC
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
S = 8-Lead SOIC
End to End Resistance
U = 50K
X9015
X
X
Physical Characteristics
Marking Includes
Manufacturer's Trademark
Resistance Value or Code
Date Code
X
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