9900-2000.1 3/31/99
#
Characteristics subject to change without notice
XDCPª is a trademark of Xicor, Inc.
FEATURES
¥ Solid-State Potentiometer
¥ Three-Wire Serial Interface
¥ 100 Wiper Tap Points
ÑWiper Position Stored in Nonvolatile Memory
and Recalled on Power-up
¥ 99 Resistive Elements, Log Taper
ÑTemperature Compensated
ÑEnd to End Resistance, ±15%
ÑTerminal Voltages, ±5V
¥ Low Power CMOS
ÑV
CC
= 5V
ÑActive Current, 3mA Max.
ÑStandby Current, 500µA Max.
¥ High Reliability
ÑEndurance, 100,000 Data Changes per Bit
ÑRegister Data Retention, 100 Years
¥ X9C303, 32 k
Ω
¥ Packages
Ñ8 Lead TSSOP
Ñ8 Lead SOIC
Ñ8 Pin DIP
DESCRIPTION
The Xicor X9C303 is a digitally-controlled (DCP)
potentiometer. 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 elements.
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 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 application
advantages; (1) the variability and reliability of a solid-
state potentiometer, (2) the ßexibility of computer-based
digital controls, and (3) the use of nonvolatile memory for
potentiometer settings retention.
X9C303
Digitally Controlled (XDCP
ª
) Potentiometer
A
PPLICATION
N
OTE
A V A I L A B L E
AN42 ¥ AN44Ð48 ¥ AN50 ¥ AN52 ¥ AN53 ¥ AN71 ¥ AN92
Terminal Voltage ±5V, 100 Taps, Log Taper
FUNCTIONAL DIAGRAM
7-BIT
UP/DOWN
COUNTER
7-BIT
NONVOLATILE
MEMORY
STORE AND
RECALL
CONTROL
CIRCUITRY
ONE
OF
HUNDRED
DECODER RESISTOR
ARRAY
RL/VL
RW/VW
RH/VH
U/D
INC
CS
TRANSFER
VCC
ONE-
GATES
99
98
97
96
2
1
0
VSS
X9C303
#
PIN DESCRIPTIONS
V
H
and V
L
The high (V
H
) and low (V
L
) terminals of the device are
equivalent to the Þxed terminals of a mechanical
potentiometer. The minimum voltage is Ð5V and the
maximum is +5V. It should be noted that the terminology
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 control
inputs. The wiper terminal series resistance is typically
40
Ω
.
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 device
will be placed in the low power standby mode until the
device is selected once again.
PIN CONFIGURATION
PIN NAMES
POTENTIOMETER RELATIONSHIPS
VCC
CS
VL
VW
INC
U/D
VH
VSS
1
2
3
4
8
7
6
5
X9C303
DIP/SOIC/(TSSOP)
(CS)
(VCC)
(INC)
(U/D)
(VL)
(VW)
(VSS)
(VH)
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
VL
VH
(VS)R99
R98
R2
R1
S100
S99
S98
S3
S2
S1
VW
Gi20LogR1R2. . . Ri
+++
RTOTAL
------------------------------------------------- VW
VS
--------- VL0V=()==
R1R2. . . R99
+++ 33KΩ@R
TOTAL
=
(Refer Test Circuit 1)
Running H/F 1
#
PRINCIPLES OF OPERATION
There are three sections of the X9C303: 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 Þxed 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 Òmake
before breakÓ 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 signiÞcant 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 memory
whenever CS transistions 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 latest
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 position
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
DonÕt Care:
Changes
Allowed
Changing:
State Not
Known
N/A Center Line
is High
Impedance
X9C303
#
ABSOLUTE MAXIMUM RATINGS*
Temperature under Bias .........................Ð65¡C to +135¡C
Storage Temperature..............................Ð65¡C to +150¡C
Voltage on CS, INC, U/D and V
CC
with Respect to V
SS
...................................... Ð1V to +7V
Voltage on V
H
and V
L
Referenced to V
SS
........................................ Ð8V to +8V
∆
V = |V
H
ÐV
L
|
X9C303 .................................................................... 10V
Lead Temperature (Soldering, 10 seconds) ......... +300¡C
Wiper Current ...........................................................±1mA
*COMMENT
Stresses above those listed under ÒAbsolute Maximum
RatingsÓ 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 speciÞcation is
not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device
reliability.
ANALOG CHARACTERISTICS
Electrical Characteristics
End-to-End Resistance Tolerance .......................... ±15%
Power Rating at 25¡C
X9C303 ................................................................10mW
Wiper Current ..................................................±1mA Max.
Typical Wiper Resistance .............................. 40
Ω
at 1mA
Typical Resistor Noise ............23 nV (RMS)/ÖHz at 1 KHz
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)
) Ð log(V
w(n-1)
) = 0.045±0.003
for tap n = 2 Ð 99
Temperature Coefficient
(Ð40¡C to +85¡C)
X9C303 ........................................... ±400 ppm/¡C Typical
Ratiometric Temperature CoefÞcient ..................±20 ppm
Wiper Adjustability
Unlimited Wiper Adjustment (Non-Store operation)
Wiper Position Store
Operations.........................100,000 Data Changes per Bit
Physical Characteristics
Marking Includes
ManufacturerÕs 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%
% Total Resistance
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(VH-VW)
R(VW-VL)
X9C303
#
Test Circuit #1
TEST POINT
VW
VH
VL
VS
D.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified.)
STANDARD PARTS
Symbol Parameter
Limits
Units Test ConditionsMin. 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 200 500 µA CS = V
CC
Ð 0.3V, U/D and INC =
V
SS
or V
CC
Ð 0.3V
I
LI
CS, INC, U/D Input
Leakage Current
±10 µA V
IN
= V
SS
to V
CC
V
IH
CS, INC, U/D Input HIGH
Voltage
2V
CC
+ 1 V
V
IL
CS, INC, U/D Input LOW
Voltage
Ð1 0.8 V
R
W
Wiper Resistance 40 100
Ω
Max. Wiper Current ±1mA
V
H
V
H
Terminal Voltage Ð5 +5 V
V
L
V
L
Terminal Voltage Ð5 +5 V
C
IN(2)
CS, INC, U/D Input
Capacitance
10 pF V
CC
= 5V, V
IN
= V
SS
,
T
A
= 25¡C, f = 1MHz
C
H
/C
L
/
C
W
Potentiometer
Capacitance
10/10/25 pF See Circuit 3
Part Number Maximum Resistance Wiper Increments Minimum Resistance
X9C303 32K
Ω
Log Taper 40
Ω
Typical
RECOMMENDED OPERATING CONDITIONS
Temperature Min. Max.
Commercial 0¡C +70¡C
Industrial Ð40¡C +85¡C
Military Ð55¡C +125¡C
Supply Voltage Limits
X9C303 5V ±10%
Test Circuit #2
FORCE
CURRENT
VL
VW
VH
TEST POINT
Circuit #3 SPICE Macromodel
CW
RTOTAL
RHRL
CH
RW
10pF
CL
10pF
25pF
Running H/F 1
#
Notes: (1) Typical values are for TA = 25¡C and nominal supply voltage.
(2) This parameter is periodically sampled and not 100% tested.
Running H/F 1
#
A.C. CONDITIONS OF TEST
A.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified)
A.C. TIMING
Notes: (3) Typical values are for TA = 25¡C and nominal supply voltage.
Input Pulse Levels 0V to 3V
Input Rise and Fall Times 10ns
Input Reference Levels 1.5V
Symbol Parameter
Limits
UnitsMin. Typ.(3) Max.
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 20 ms
tIW INC to VW Change 100 500 µs
tCYC INC Cycle Time 4 µs
tR, tF(4) INC Input Rise and Fall Time 500 ns
tPU(4) Power up to Wiper Stable 500 µs
tR VCC(4) VCC Power-up Rate 0.2 50 mV/µs
CS
INC
U/D
VW
tCI tIL tIH
tCYC
tID tDI
tIW
MI (8)
tIC tCPH
tFtR
10%
90% 90%
Running H/F 1
#
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∞ Ð 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 PLACESFOOTPRINT
Running H/F 1
#
PACKAGING INFORMATION
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
8-LEAD PLASTIC, TSSOP, PACKAGE TYPE V
See Detail ÒAÓ
.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∞ Ð 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
Running H/F 1
#
ORDERING INFORMATION
Temperature Range
Blank = Commercial = 0°C to +70°C
I = Industrial = Ð40°C to +85°C
Package
P = 8-Lead Plastic DIP
S8 = 8-Lead SOIC
V8 = 8-Lead TSSOP
X9C303 X X
LIMITED WARRANTY
Devices sold by Xicor, Inc. are covered by the warranty and patent indemniÞcation 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 Þtness for any purpose. Xicor, Inc. reserves the
right to discontinue production and change speciÞcations 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.
XicorÕs 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 signiÞcant 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.
