Low Noise, Low Power
X9015
Digitally-Controlled Potentiometer
FEATURES
DESCRIPTION
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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 RW/VW 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.
32 Taps
Three-wire Up/Down Serial Interface
VCC = 2.7V & 5V
Operating ICC = 50µA Max.
Standby current = 1µA Max.
RTOTAL = 50KΩ
Packages, SOIC-8
The X9015 can be used in a wide variety of applications
that require a digitally controlled variable resistor to set
analog values.
FUNCTIONAL DIAGRAMS
U/D
INC
CS
VCC (Supply Voltage)
CONTROL
DEVICE SELECT
(CS)
RH/VH
31
30
29
RH/VH
UP/DOWN
(U/D)
INCREMENT
(INC)
5-BIT
UP/DOWN
COUNTER
28
ONE
OF
THIRTY TWO
DECODER
RW/VW
RL/VL
TRANSFER
GATES
RESISTOR
ARRAY
2
VSS (Ground)
GENERAL
VCC
VSS
CONTROL
CIRCUITRY
1
0
RL/VL
RW/VW
DETAILED
9900-2009.3 9/20/99 PS
1
Characteristics subject to change without notice
X9015
PIN CONFIGURATION
PIN DESCRIPTIONS
RH/VH and RL/VL
The high (RH/VH) and low (RL/VL) terminals of the
X9015 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.
SOIC
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 at VCC = 5V. At power up the wiper
position is at tap #15 (VL/RL = tap #0).
INC
1
U/D
RH/VH
2
VSS
4
3
X9015
8
VCC
7
6
CS
RL/VL
5
RW/VW
PIN NAMES
Symbol
Up/Down (U/D)
The U/D input controls the direction of the wiper
movement and whether the tap postion is incremented or
decremented.
RH/VH
High Terminal
RW/VW
Wiper Terminal
RL/VL
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.
2
Description
Low Terminal
VSS
Ground
VCC
Supply Voltage
U/D
Up/Down Control Input
INC
Increment Control Input
CS
Chip Select Control Input
X9015
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 powerup/down cycle.
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 resistor array to the wiper output. The resistor array is comprised of 31 individual resistors connected in series.
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.
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.
MODE SELECTION
CS
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.
INC
U/D
Mode
L
H
Wiper Up
L
L
Wiper Down
X
X
Standby Current
L
X
Return to standby
H
SYMBOL TABLE
WAVEFORM
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.
3
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
X9015
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
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
X9015
5V ±10%
Industrial
–40°C
+85°C
X9015-2.7
2.7V to 5.5V
POTENTIOMETER CHARACTERISTICS (Over recommended operating conditions unless otherwise stated.)
Limits
Symbol
Parameter
Min.
Typ.
Max.
Units
–20
+20
%
RTOTAL
End to End Resistance Variation
VVH
VH Terminal Voltage
0
VCC
V
VVL
VL Terminal Voltage
0
VCC
V
10
mW
Power Rating
Test Conditions/Notes
RTOTAL ≤ 50KΩ
RW
Wiper Resistance
200
400
Ω
IW = 1mA, VCC = 5V
RW
Wiper Resistance
400
1000
Ω
IW = 1mA, VCC = 2.7V
IW
Wiper Current
±1
mA
Noise
Resolution
-120
dBV
3
%
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]
(1)
RTOTAL Temperature Coefficient
±300
Ratiometric Temperature Coefficient
CH/CL/CW
Notes:
Ref: 1kHz
ppm/°C
±20
Potentiometer Capacitances
10/10/25
ppm/°C
pF
See circuit #3
(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/31.
(4) Typical values are for TA = 25°C and nominal supply voltage.
(5) This parameter is periodically sampled and not 100% tested.
4
X9015
D.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified.)
Limits
Symbol
Parameter
Typ.(4)
Min.
Max.
Units
Test Conditions
ICC1
VCC Active Current
(Increment)
50
µA
CS = VIL, U/D = VIL or VIH and
INC = 0.4V @ max. tCYC
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,
TA = 25°C, f = 1MHz
Capacitance
Test Circuit #1
Circuit #3 SPICE Macromodel
Test Circuit #2
VH/RH
RTOTAL
VH/RH
TEST POINT
RH
CW
CH
VS
TEST POINT
VW/RW
VL/RL
VLL/RL
VW/RW
VW
FORCE
CURRENT
10pF
25pF
10pF
RW
5
CL
RL
X9015
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
Min.
Typ.(6)
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
tCPH
CS Deselect Time
100
ns
tIW
INC to Vw Change
tCYC
INC Cycle Time
1
tR, tF(7)
INC Input Rise and Fall Time
tPU(7)
Power up to Wiper Stable
tR VCC(7)
VCC Power-up Rate
5
µs
4
µs
500
0.2
µs
5
µs
50
V/ms
A.C. TIMING
CS
tIC
tCYC
tCI
tIL
(Stand by)
tCPH
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.
6
X9015
PERFORMANCE CHARACTERISTICS (TYPICAL)
TYPICAL NOISE
0
-10
-20
-30
-40
-50
Noise (dB)
-60
-70
-80
-90
-100
-110
-120
-130
-140
-150
0
10
20
30
40
50
60
70
80
90
100
110 120
130 140
150 160
170 180
190 200
Frequency (KHz)
TYPICAL RTOTAL vs. TEMPERATURE
10000
9800
9600
9400
Rtotal
9200
9000
8800
8600
8400
8200
8000
-55
-45
-35
-25
-15
-5
5
15
35
45
25
Temperature
55
65
75
85
95
105
115 125 C°
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
Temperature
7
55
65
75
85
95
105
115
125
°C
X9015
TYPICAL WIPER RESISTANCE
800
700
600
Rw (Ohms)
500
400
300
200
100
0
0
2
4
6
8
10
12
14
16
Tap
18
20
22
24
26
28
30
TYPICAL ABSOLUTE % ERROR PER TAP POSITION
40.0%
30.0%
Absolute % Error
20.0%
10.0%
0.0%
-10.0%
-20.0%
-30.0%
-40.0%
0
3
6
9
12
15
18
21
24
27
30
18
21
24
27
30
Tap
TYPICAL RELATIVE % ERROR PER TAP POSITION
20.0%
15.0%
Relative % Error
10.0%
5.0%
0.0%
-5.0%
-10.0%
-15.0%
-20.0%
0
3
6
9
12
15
Tap
8
32
VCC = 2.7V
X9015
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
VR
VR
VH
VW
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
R2
+V
–5V
R1
VW
VOUT = VW
(a)
Voltage Regulator
VIN
VO = (1+R2/R1)VS
Offset Voltage Adjustment
VO (REG)
317
(b)
R1
Comparator with Hysterisis
R2
VS
R1
VS
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)
9
X9015
SOIC PACKAGING INFORMATION
8-LEAD PLASTIC SMALL OUTLINE GULL WING PACKAGE TYPE S
0.150 (3.80)
0.158 (4.00)
0.228 (5.80)
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)
0.020 (0.50) X 45°
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
NOTE: ALL DIMENSIONS IN INCHES (IN P ARENTHESES IN MILLIMETERS)
10
0.030"
TYPICAL
8 PLACES
X9015
ORDERING INFORMATION
X9015
X
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
S = 8-Lead SOIC
End to End Resistance
U = 50KΩ
Physical Characteristics
Marking Includes
Manufacturer’s Trademark
Resistance Value or Code
Date Code
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.
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