X9318
®
Data Sheet
September 14, 2005
Digitally Controlled Potentiometer
(XDCP™)
DESCRIPTION
The Intersil X9318 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.
FEATURES
•
•
•
•
•
•
•
•
•
•
Solid-state potentiometer
3-wire serial interface
Terminal voltage, 0 to +8V
100 wiper tap points
—Wiper position stored in nonvolatile memory
and recalled on power-up
99 resistive elements
—Temperature compensated
—End to end resistance range ± 20%
Low power CMOS
—VCC = 5V
—Active current, 3mA max.
—Standby current, 1mA max.
High reliability
—Endurance, 100,000 data changes per bit
—Register data retention, 100 years
RTOTAL value = 10kΩ
Packages
—8 Ld SOIC and DIP
Pb-free plus anneal available (RoHS compliant)
The potentiometer is implemented by a resistor array
composed of 99 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 for voltage control or as a two-terminal variable resistor for current control in a wide variety of applications.
PIN CONFIGURATION
DIP/SOIC
APPLICATIONS
•
•
•
•
•
FN8184.1
8
VCC
7
CS
3
6
RL
4
5
RW
INC
1
U/D
2
RH
VSS
X9318
LCD bias control
DC bias adjustment
Gain and offset trim
Laser diode bias control
Voltage regulator output control
BLOCK DIAGRAM
U/D
INC
CS
VCC (Supply Voltage)
Control
and
Memory
97
7-Bit
Nonvolatile
Memory
RW
Device Select
(CS)
RH
99
98
RH
Up/Down
(U/D)
Increment
(INC)
Up/Down
Counter
RL
One 96
of
One
Hundred
Decoder
Wiper
Switches
Resistor
Array
2
VSS (Ground)
General
VCC
VSS
Store and
Recall
Control
Circuitry
1
0
RL
RW
Detailed
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
XDCP is a trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2005. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
X9318
Ordering Information
PART NUMBER
PART MARKING
RTOTAL (kΩ)
TEMP RANGE (°C)
PACKAGE
10
0 to 70
8 Ld PDIP
-40 to 85
8 Ld PDIP
X9318WP8
X9318WP
X9318WP8I
X9318WP I
X9318WS8*
X9318W
0 to 70
8 Ld SOIC (150 mil)
X9318WS8Z* (Note)
X9318W Z
0 to 70
8 Ld SOIC (150 mil) (Pb-free)
X9318WS8I*
X9318W I
-40 to 85
8 Ld SOIC (150 mil)
X9318WS8IZ* (Note)
X9318W Z I
-40 to 85
8 Ld SOIC (150 mil) (Pb-free)
*Add "T1" suffix for tape and reel.
NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate
termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL
classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
PIN DESCRIPTIONS
DIP/SOIC
Symbol
Brief Description
1
INC
Increment. Toggling INC while CS is low moves the wiper either up or down.
2
U/D
Up/Down. The U/D input controls the direction of the wiper movement.
3
RH
The high terminal is equivalent to one of the fixed terminals of a mechanical potentiometer.
4
VSS
Ground.
5
RW
The wiper terminal is equivalent to the movable terminal of a mechanical potentiometer.
6
The low terminal is equivalent to one of the fixed terminals of a mechanical potentiometer.
7
RL
CS
8
VCC
Supply Voltage.
Chip Select. The device is selected when the CS input is LOW, and de-selected when CS is high.
2
FN8184.1
September 14, 2005
X9318
ABSOLUTE MAXIMUM RATINGS
COMMENT
Junction Temperature under bias...... -65°C to +135°C
Storage temperature ......................... -65°C to +150°C
Voltage on CS, INC, U/D and VCC
with respect to VSS ................................. -1V to +7V
RH, RW, RL to ground..........................................+10V
Lead temperature (soldering 10s) ..................... 300°C
IW (10s) ..............................................................±6mA
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.
POTENTIOMETER CHARACTERISTICS
(VCC = 5V ± 10%, TA = Full Operating Temperature Range unless otherwise stated)
Limits
Symbol
VRH/RL
Parameter
Min.
Typ.(4)
Unit
Test Conditions/Notes
End to end resistance tolerance
-20
+20
%
See ordering information
for values
RH/RL terminal voltage
VSS
8
V
VSS = 0V
25
mW
200
Ω
+3.0
mA
See test circuit
-120
dBV
Ref: 1kHz
1
%
Power rating
RW
Wiper resistance
IW
Wiper current(5)
Noise(7)
40
-3.0
Resolution
Absolute linearity(1)
Relative linearity(2)
-1
-0.2
RTOTAL temperature coefficient(5)
Ratiometric temperature coefficient(5),(6)
-20
3
MI(3)
+0.2
MI(3)
4.5
IW = 1mA
V(RH) = 8V,
V(RL) = 0V
ppm/°C
+20
10/10/25
)
Supply Voltage
+1
±300
CH/CL/CW(5 Potentiometer capacitances
VCC
Max.
ppm/°C
pF
5.5
See equivalent circuit
V
FN8184.1
September 14, 2005
X9318
D.C. OPERATING CHARACTERISTICS
(VCC = 5V ± 10%, TA = Full Operating Temperature Range unless otherwise stated)
Limits
Symbol
Parameter
Min.
Typ.(4)
Max.
Unit
1
3
mA
CS = VIL, U/D = VIL or VIH and
INC = 0.4V/2.4V @ min. tCYC
RL, RH, RW not connected
300
1000
µA
CS ≥ 2.4V, U/D and INC = 0.4V
RL, RH, RW not connected
VIN = VSS to VCC
ICC
VCC active current (Increment)
ISB
Standby supply current
ILI
CS, INC, U/D input leakage current
-10
+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
(VCC = 5V ± 10%, TA = Full Operating Temperature Range)
Parameter
Min.
Unit
Minimum endurance
100,000
Data changes per bit
Data retention
100
Years
Notes: (1) Absolute linearity is utilized to determine actual wiper voltage versus expected voltage = [V(RW(n)(actual)) - V(RW(n)(expected))]/MI
V(RW(n)(expected)) = n(V(RH) - V(RL))/99 + V(RL), with n from 0 to 99.
(2) Relative linearity is a measure of the error in step size between taps = [V(RW(n+1)) - (V(RW(n)) - MI)]/MI
(3) 1 Ml = Minimum Increment = [V(RH) - V(RL)]/99.
(4) Typical values are for TA = 25°C and nominal supply voltage.
(5) This parameter is not 100% tested.
(6) Ratiometric temperature coefficient = (V(RW)T1(n) - V(RW)T2(n))/[V(RW)T1(n)(T1 - T2) x 106], with T1 & T2 being 2 temperatures, and n
from 0 to 99.
(7) Measured with wiper at tap position 31, RL grounded, using test circuit.
Test Circuit
Equivalent Circuit
RTOTAL
Test Point
RH
CW
CH
RW
Force
Current
CL
RL
10pF
25pF
10pF
RW
A.C. CONDITIONS OF TEST
Input pulse levels
0.8V to 2.0V
Input rise and fall times
10ns
Input reference levels
1.4V
4
FN8184.1
September 14, 2005
X9318
A.C. OPERATING CHARACTERISTICS
(VCC = 5V ± 10%, TA = Full Operating Temperature Range unless otherwise stated)
Limits
Symbol
tCl
Parameter
Min.
Typ.(4)
Unit
Max.
CS to INC setup
100
ns
(5)
INC HIGH to U/D change
100
ns
(5)
U/D to INC setup
1
µs
tlL
INC LOW period
1
µs
tlH
INC HIGH period
1
µs
tlC
INC inactive to CS inactive
1
µs
tCPHS
CS deselect time (STORE)
20
ms
CS deselect time (NO STORE)
1
µs
tlD
tDI
tCPHNS(5
)
tIW
tCYC
tR, tF(5)
tPU(5)
tR VCC(5)
INC to RW change
100
500
µs
INC input rise and fall time
500
µs
Power-up to wiper stable
500
µs
50
V/ms
INC cycle time
4
VCC power-up rate
µs
0.2
POWER-UP AND DOWN REQUIREMENTS
The recommended power-up sequence is to apply VCC/VSS first, then the potentiometer voltages. During power-up,
the data sheet parameters for the DCP do not fully apply until 1 millisecond after VCC reaches its final value. The VCC
ramp spec is always in effect. In order to prevent unwanted tap position changes, or an inadvertant store, bring the
CS and INC high before or concurrently with the VCC pin on powerup.
A.C. TIMING
CS
tCYC
tCI
tIL
tIC
tIH
tCPHNS
tCPHS
90%
90%
10%
INC
tID
tDI
tF
tR
U/D
tIW
MI
RW
5
(3)
FN8184.1
September 14, 2005
X9318
PIN NAMES
PIN DESCRIPTIONS
RH and RL
Symbol
The high (RH) and low (RL) terminals of the X9318 are
equivalent to the fixed terminals of a mechanical
potentiometer. The terminology of RL and RH 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.
Description
RH
High terminal
RW
Wiper terminal
RL
Low terminal
VSS
Ground
VCC
Supply voltage
RW
U/D
Up/Down control input
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 40Ω.
INC
Increment control input
CS
Chip select control input
Up/Down (U/D)
The U/D input controls the direction of the wiper movement and whether the counter 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. 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 X9318
will be placed in the low power standby mode until the
device is selected once again.
PIN CONFIGURATION
DIP/SOIC
8
VCC
7
CS
3
6
RL
4
5
RW
INC
1
U/D
2
RH
VSS
X9318
6
PRINCIPLES OF OPERATION
There are three sections of the X9318: the control
section, the nonvolatile memory, and the resistor
array. The 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 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. Electronic switches at either end
of the array and between each resistor provide an
electrical connection to the wiper pin, RW.
The wiper acts like its mechanical equivalent and does
not move beyond the first or 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.
FN8184.1
September 14, 2005
X9318
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.
MODE SELECTION
CS
INC
U/D
Mode
L
H
Wiper up
L
L
Wiper down
H
X
Store wiper position to
nonvolatile memory
X
X
Standby
The value of the counter is stored in nonvolatile memory whenever CS transitions HIGH while the INC input
is also HIGH.
L
X
No store, return to standby
L
H
Wiper Up (not recommended)
The system may select the X9318, 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 powerup/down cycle recalled the previously stored data.
L
L
Wiper Down
(not recommended)
H
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.
7
FN8184.1
September 14, 2005
X9318
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
VREF
VREF
RH
RW
RL
I
Three terminal potentiometer;
variable voltage divider
Two terminal variable resistor;
variable current
Basic Circuits
Buffered Reference Voltage
Single Supply Inverting Amplifier
Cascading Techniques
R1
+V
+V
+V
R1
+5V
RW
VREF
+
VS
LMC7101
VOUT
–
+8V
R2
X
RW
–
100K
+V
VO
+
+8V
LMC7101
(a)
Voltage Regulator
VIN
100K
RW
VOUT = VW/RW
(b)
VO = (R2/R1)VS
Offset Voltage Adjustment
VO (REG)
317
R1
Comparator with Hysteresis
R2
VS
R1
VS
LT311A
+12V
100kΩ
–
+
VO
–
+
Iadj
10kΩ
VO (REG) = 1.25V (1+R2/R1)+Iadj R2
10kΩ
}
LMC7101
10kΩ
}
R2
VO
R1
R2
VUL = {R1/(R1+R2)} VO(max)
VLL = {R1/(R1+R2)} VO(min)
+12V
(for additional circuits see AN115)
8
FN8184.1
September 14, 2005
X9318
PACKAGING INFORMATION
8-Lead Plastic Small Outline Package, Type S (8-lead SOIC)
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)
FOOTPRINT
0.030"
Typical
8 Places
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
9
FN8184.1
September 14, 2005
X9318
PACKAGING INFORMATION
8-Lead Plastic, DIP, Package Code P8
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)
0.020 (0.51)
0.016 (0.41)
0.110 (2.79)
0.090 (2.29)
.073 (1.84)
Max.
Typ. 0.010 (0.25)
0.060 (1.52)
0.020 (0.51)
0.325 (8.25)
0.300 (7.62)
0°
15°
NOTE:
1. ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
2. PACKAGE DIMENSIONS EXCLUDE MOLDING FLASH
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
10
FN8184.1
September 14, 2005