1
FN8223.0
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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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.
X9C303
Terminal Voltage 5V, 100 Taps, Log Taper
Digitally Controlled Potentiometer
(XDCPTM)
FEATURES
Solid-state potentiometer
Three-wire serial interface
100 wiper tap points
--Wiper position stored in nonvolatile memory
and recalled on power-up
99 resistive elements, log taper
--Temperature compensated
--End to end resistance, 15%
--Terminal voltages, 5V
Low power CMOS
--V
CC
= 5V
--Active current, 3mA max.
--Standby current, 750A max.
High reliability
--Endurance, 100,000 data changes per bit
--Register data retention, 100 years
X9C303, 32k
Packages
--8-lead TSSOP
--8-lead SOIC
--8-pin DIP
DESCRIPTION
The Intersil X9C303 is a digitally controlled potentiom-
eter (XDCP). The device consists of a resistor array,
wiper switches, a control section, and nonvolatile
memory. The wiper position is controlled by a three-
wire interface.
The resistor array is composed of 99 resistive ele-
ments. Between each element and at either end are
tap points accessible to the wiper terminal. The posi-
tion 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 potentio-
meter or as a two-terminal variable resistor in a wide
variety of applications ranging from control, to signal
processing, to parameter adjustment. Digitally-
controlled potentiometers provide three powerful appli-
cation advantages; (1) the variability and reliability of a
solid-state potentiometer, (2) the flexibility of com-
puter-based digital controls, and (3) the use of nonvol-
atile memory for potentiometer settings retention.
BLOCK DIAGRAM
7-Bit
Up/Down
Counter
7-Bit
Nonvolatile
Memory
Store and
Recall
Control
Circuitry
One
of
Hundred
Decoder
Resistor
Array
R
L/
V
L
R
W/
V
W
R
H/
V
H
U/D
INC
CS
Transfer
V
CC
One-
Gates
99
98
97
96
2
1
0
V
SS
Data Sheet
March 11, 2005
2
FN8223.0
March 11, 2005
PIN DESCRIPTIONS
V
H
and V
L
The high (V
H
) and low (V
L
) terminals of the device are
equivalent to the fixed terminals of a mechanical
potentiometer. The minimum voltage is 5V and the
maximum is +5V. It should be noted that the terminol-
ogy of V
L
and 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.
V
W
V
W
is the wiper terminal, equivalent to the movable
terminal of a mechanical potentiometer. The position
of the wiper within the array is determined by the con-
trol inputs. The wiper terminal series resistance is typi-
cally 40
.
Up/Down (U/D)
The U/D input controls the direction of the wiper
movement and whether the counter is incriminated or
decremented.
Increment (INC)
The
INC
input is negative-edge triggered. Toggling
INC will move the wiper and either increment or decre-
ment 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 device
will be placed in the low power standby mode until the
device is selected once again.
PIN CONFIGURATION
PIN NAMES
POTENTIOMETER RELATIONSHIPS
V
CC
CS
V
L
V
W
INC
U/D
V
H
V
SS
1
2
3
4
8
7
6
5
X9C303
DIP/SOIC/(TSSOP)
(CS)
(V
CC
)
(INC)
(U/D)
(V
L
)
(V
W
)
(V
SS
)
(V
H
)
Symbol
Description
V
H
High Terminal (Potentiometer)
V
W
Wiper Terminal (Potentiometer)
V
L
Low Terminal (Potentiometer)
V
SS
Ground
V
CC
Supply Voltage
U/D
Up/Down Control Input
INC
Increment Control Input
CS
Chip Select Control Input
NC
No Connection
V
L
V
H
(V
S
)
R99
R98
R2
R1
S100
S99
S98
S3
S2
S1
V
W
Gi 20Log
R1 R2 . . . Ri
+
+
+
RTOTAL
-------------------------------------------------
VW
VS
--------- VL 0V
=
(
)
=
=
R1 R2 . . . R99
+
+
+
3
k
@
RTOTAL
=
(Refer Test Circuit 1)
X9C303
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FN8223.0
March 11, 2005
PRINCIPLES OF OPERATION
There are three sections of the X9C303: the input con-
trol, counter and decode section; the nonvolatile mem-
ory; 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 com-
prised 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 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 last counter
position stored will be maintained in the nonvolatile
memory. When power is restored, the contents of the
memory are recalled and the counter is reset to the
value last stored.
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 mem-
ory whenever CS transitions HIGH while the INC input
is also HIGH.
The system may select the X9C303, move the wiper,
and deselect the device without having to store the lat-
est wiper position in nonvolatile memory. The wiper
movement is performed as described above; once the
new position is reached, the system would the keep
INC LOW while taking CS HIGH. The new wiper posi-
tion would be maintained until changed by the system
or until a power-down/up cycle recalled the previously
stored data.
This would allow 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
SYMBOL TABLE
CS
INC
U/D
Mode
L
H
Wiper Up
L
L
Wiper Down
H
X
Store Wiper Position
H
X
X
Standby Current
L
X
No Store, 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
X9C303
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FN8223.0
March 11, 2005
ABSOLUTE MAXIMUM RATINGS
Temperature under bias .................... -65C to +135C
Storage temperature ......................... -65C to +150C
Voltage on CS, INC, U/D and V
CC
with respect to V
SS
.................................. -1V to +7V
Voltage on V
H
and V
L
referenced to V
SS
.................................... -8V to +8V
V = |V
H
- V
L
| X9C303 ..........................................10V
Lead temperature (soldering, 10 seconds)...... +300C
Wiper current......................................................1mA
COMMENT
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 con-
ditions for extended periods may affect device reliability.
ANALOG CHARACTERISTICS
Electrical Characteristics
End-to-end resistance tolerance ........................ 15%
Power rating at 25C X9C303 ........................... 10mW
Wiper current ............................................ 1mA Max.
Typical wiper resistance ...........................40
at 1mA
Typical resistor
noise .........................23 nV (RMS)/
Hz at 1kHzPHZ
Typical charge pump noise . 20 mV (RMS) @ 2.5 MHz
Relative Variation
Relative variation is a measure of the error in step size
between
taps = log (V
w(n)
) - log (V
w(n - 1)
) = 0.045 0.003
for tap n = 2 - 99
Temperature Coefficient
(-40C to +85C) X9C303 .......... 400 ppm/C Typical
Ratiometric temperature coefficient ..............20 ppm
Wiper Adjustability
Unlimited Wiper Adjustment (Non-Store operation)
Wiper Position Store
Operations ...................100,000 Data Changes per Bit
Physical Characteristics
Marking Includes
Manufacturer's Trademark
Resistance Value or Code
Date Code
Typical Electrical Taper
100.0%
90.0%
80.0%
70.0%
60.0%
50.0%
40.0%
30.0%
20.0%
10.0%
0.0%
%
To
tal Res
i
stan
ce
0
3
6
9
12
15
18
21
24
27
30
33
36
39
42
45
48
51
54
57
60
63
66
69
72
75
78
81
84
87
90
93
96
99
Tap
R(V
H
- V
W
)
R(V
W
- V
L
)
X9C303
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FN8223.0
March 11, 2005
D.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified.)
Standard Parts
Notes: (1) Typical values are for T
A
= 25C and nominal supply voltage.
(2) This parameter is periodically sampled and not 100% tested.
A.C. CONDITIONS OF TEST
Symbol
Parameter
Limits
Unit
Test Conditions
Min.
Typ.
(1)
Max.
I
CC
V
CC
active current
1
3
mA
CS = V
IL
, U/D = V
IL
or V
IH
and
INC = 0.4V to 2.4V @ max. t
CYC
I
SB
Standby supply current
200
750
A
CS = V
CC
- 0.3V, U/D and
INC = V
SS
or V
CC
- 0.3V
I
LI
CS, INC, U/D input leakage
current
10
A
V
IN
= V
SS
to V
CC
V
IH
CS, INC, U/D input HIGH
voltage
2
V
CC
+ 1
V
V
IL
CS, INC, U/D input LOW
voltage
-1
0.8
V
R
W
Wiper resistance
40
100
Max. Wiper Current 1mA
V
H
V
H
terminal voltage
-5
+5
V
V
L
V
L
terminal voltage
-5
+5
V
C
IN (2)
CS, INC, U/D input capacitance
10
pF
V
CC
= 5V, V
IN
= V
SS
,
T
A
= 25C, f = 1MHz
C
H
/C
L
/C
W
Potentiometer capacitance
10/10/25
pF
See Circuit 3
Test Circuit #1
Test Point
V
W
V
H
V
L
V
S
Test Circuit #2
Force
V
L
V
W
V
H
Test Point
Current
Circuit #3 SPICE Macro Model
C
W
R
TOTAL
R
H
R
L
C
H
R
W
10pF
C
L
10pF
25pF
RECOMMENDED OPERATING CONDITIONS
Temperature
Min.
Max.
Commercial
0C
+70C
Industrial
40C
+85C
Military
55C
+125C
Supply Voltage
Limits
X9C303
5V 10%
Part Number
Maximum Resistance
Wiper Increments
Minimum Resistance
X9C303
32k
Log Taper
40
Typical
Input pulse levels
0V to 3V
Input rise and fall times
10ns
Input reference levels
1.5V
X9C303
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FN8223.0
March 11, 2005
A.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified)
A.C. TIMING
Notes: (3) Typical values are for T
A
= 25C and nominal supply voltage.
(4) This parameter is periodically sampled and not 100% tested.
(5) 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
Unit
Min.
Typ.
(3)
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
20
ms
t
IW
INC to V
W
change
100
500
s
t
CYC
INC cycle time
4
s
t
R,
t
F (4)
INC input rise and fall time
500
ns
t
PU (4)
Power-up to wiper stable
500
s
t
R
V
CC (4)
V
CC
power-up rate
0.2
50
mV/s
CS
INC
U/D
V
W
t
CI
t
IL
t
IH
t
CYC
t
ID
t
DI
t
IW
MI
(8)
t
IC
t
CPH
t
F
t
R
10%
90%
90%
X9C303
7
FN8223.0
March 11, 2005
PACKAGING INFORMATION
NOTE:
1. ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
2. PACKAGE DIMENSIONS EXCLUDE MOLDING FLASH
0.020 (0.51)
0.016 (0.41)
0.150 (3.81)
0.125 (3.18)
0.110 (2.79)
0.090 (2.29)
0.430 (10.92)
0.360 (9.14)
0.300
(7.62) Ref.
Pin 1 Index
0.145 (3.68)
0.128 (3.25)
0.025 (0.64)
0.015 (0.38)
Pin 1
Seating
0.065 (1.65)
0.045 (1.14)
0.260 (6.60)
0.240 (6.10)
0.060 (1.52)
0.020 (0.51)
Typ. 0.010 (0.25)
0
15
8-Lead Plastic Dual In-Line Package Type P
Half Shoulder Width On
All End Pins Optional
.073 (1.84)
Max.
0.325 (8.25)
0.300 (7.62)
Plane
X9C303
8
FN8223.0
March 11, 2005
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
X9C303
9
FN8223.0
March 11, 2005
PACKAGING INFORMATION
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
8-Lead Plastic, TSSOP, Package Type V
See Detail "A"
.031 (.80)
.041 (1.05)
.169 (4.3)
.177 (4.5)
.252 (6.4) BSC
.025 (.65) BSC
.114 (2.9)
.122 (3.1)
.002 (.05)
.006 (.15)
.047 (1.20)
.0075 (.19)
.0118 (.30)
0 - 8
.010 (.25)
.019 (.50)
.029 (.75)
Gage Plane
Seating Plane
Detail A (20X)
(4.16) (7.72)
(1.78)
(0.42)
(0.65)
All Measurements Are Typical
X9C303
10
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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
FN8223.0
March 11, 2005
Ordering Information
Temperature Range
Blank = Commercial = 0C to +70C
I = Industrial = -40C to +85C
Package
P = 8-Lead Plastic DIP
S8 = 8-Lead SOIC
V8 = 8-Lead TSSOP
X9C303
X
X
X9C303
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