A
PPLICATION
N
OTE
A V A I L A B L E
AN20 • AN42–53 • AN71 • AN73 • AN88 • AN91–92 • AN115
Terminal Voltages ±5V, 100 Taps
X9C102/103/104/503
Digitally-Controlled (XDCP) Potentiometer
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
—Temperature Compensated
—End to End Resistance, ±20%
—Terminal Voltages, ±5V
• Low Power CMOS
—V
CC
= 5V
—Active Current, 3mA Max.
—Standby Current, 500µA Max.
• High Reliability
—Endurance, 100,000 Data Changes per Bit
—Register Data Retention, 100 Years
• X9C102 = 1 k
W
• X9C103 = 10 k
W
• X9C503 = 50 k
W
• X9C104 = 100 k
W
• Packages
—8-Lead SOIC and DIP
FUNCTIONAL DIAGRAMS
DESCRIPTION
The X9Cxxx are Xicor digitally-controlled (XDCP)
potentiometers. 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 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 or as a two-terminal variable resistor in a
wide variety of applications including:
• control
• parameter adjustments
• signal processing
U/D
INC
CS
V
CC
(Supply Voltage)
7-BIT
UP/DOWN
COUNTER
99
98
97
R
H
/V
H
Up/Down
(U/D)
Increment
(INC)
Device Select
(CS)
Control
R
H
/V
H
7-BIT
NONVOLATILE
MEMORY
and
Memory
R
W
/V
W
ONE 96
OF
ONE-
HUNDRED
DECODER
TRANSFER
GATES
RESISTOR
ARRAY
R
L
/V
L
2
STORE AND
RECALL
CONTROL
CIRCUITRY
1
0
R
L
/V
L
R
W
/V
W
Detailed
V
SS
(Ground)
General
V
CC
GND
E
2
POT
™
is a trademark of Xicor, Inc. 11/5/98
©Xicor, Inc. 1994, 1995 Patents Pending
3863-2.4 2/12/99 T2/C0/D0 SH
1
Characteristics subject to change without notice
X9C102/103/104/503
PIN DESCRIPTIONS
R
H
/V
H
and R
L
/V
L
The high (V
H
/R
H
) and low (V
L
/R
L
) terminals of the
X9C102/103/104/503 are equivalent to the fixed
terminals of a mechanical potentiometer. The
minimum voltage is –5V and the maximum is +5V. The
terminology of V
H
/R
H
and V
L
/R
L
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
V
W
/R
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 40
W
.
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 X9C102/
103/104/503 device will be placed in the low power
standby mode until the device is selected once again.
PIN NAMES
Symbol
V
H
/R
H
V
W
/R
W
V
L
/R
L
V
SS
V
CC
U/D
INC
CS
NC
DIP/SOIC
INC
U/D
V
H
/R
H
V
SS
1
2
3
4
X9C102/103/104/503
8
7
6
5
V
CC
CS
V
L
/R
L
V
W
/R
W
PIN CONFIGURATION
3863 FHD F02.2
Description
High Terminal
Wiper Terminal
Low Terminal
Ground
Supply Voltage
Up/Down Control Input
Increment Control Input
Chip Select Control Input
No Connection
2
X9C102/103/104/503
PRINCIPLES OF OPERATION
There are three sections of the X9Cxxx: 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 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 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.
INTRUCTIONS 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 X9Cxxx, 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
power-down/up cycle recalled the previously stored data.
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.
MODE SELECTION
CS
L
L
H
H
X
L
INC
U/D
H
L
X
X
X
Wiper Up
Mode
Wiper Down
Store Wiper Position
Standby Current
No Store, Return to Standby
SYMBOL TABLE
WAVEFORM
INPUTS
Must be
steady
May change
from Low to
High
May change
from High to
Low
Don’t Care:
Changes
Allowed
N/A
OUTPUTS
Will be
steady
Will change
from Low to
High
Will change
from High to
Low
Changing:
State Not
Known
Center Line
is High
Impedance
3
X9C102/103/104/503
ABSOLUTE MAXIMUM RATINGS*
Temperature under Bias .........................–65°C to +135°C
Storage Temperature..............................–65°C to +150°C
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
D
V = |V
H
–V
L
|
X9C102 ...................................................................... 4V
X9C103, X9C503, and X9C104............................... 10V
Lead Temperature (Soldering, 10 seconds).......... +300°C
RECOMMENDED OPERATING CONDITIONS
Temperature
Commercial
Industrial
Military
*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
conditions for extended periods may affect device reliability.
Min.
0°C
–40°C
–55°C
Max.
+70°C
+85°C
+125°C
3863 PGM T03.1
Supply Voltage (V
CC
)
X9C102/103/104/503
Limits
5V ±10%
3863 PGM T04.2
POTENTIOMETER CHARACTERISTICS
(Over recommended operating conditions unless otherwise stated.)
Limits
Symbol
R
TOTAL
V
VH
V
VL
Parameter
End to End Resistance Variation
V
H
Terminal Voltage
V
L
Terminal Voltage
Power Rating
Power Rating
Min.
–20
–5
–5
Typ.
Max.
+20
+5
+5
16
10
±1
Units
%
V
V
mW
mW
mA
W
dBV
%
Test Conditions/Notes
X9C102
X9C103/104/503
I
W
R
W
Wiper Current
Wiper Resistance
Noise
Resolution
Absolute Linearity
(1)
Relative Linearity
(2)
RTOTAL Temperature Coefficient
RTOTAL Temperature Coefficient
Ratiometric Temperature Coefficient
–1
–0.2
±300
±600
40
–120
1
100
Wiper Current = ±1mA
Ref. 1kHz
V
W(n)(actual)
– V
W(n)(expected)
V
W(n + 1)(actual)
– [V
W(n) + MI
]
X9C103/503/104
X9C102
see circuit #3
+1
+0.2
M
(3)
MI
(3)
ppm/°C
ppm/°C
±20
10/10/25
ppm°C
pF
C
H
/C
L
/C
W
Potentiometer Capacitances
Notes:
(1) Absolute Linearity is utilized to determine actual wiper voltage versus expected voltage = [V
W(n)(actual)
– V
W(n)(expected )
] = ±1 MI Maximum.
(2)
(3)
(4)
(5)
Relative Linearity is a measure of the error in step size between taps = V
W(n + 1)
– [V
W(n) + MI
] = +0.2 MI.
1 MI = Minimum Increment = R
TOT
/99
Typical values are for T
A
= 25°C and nominal supply voltage.
This parameter is periodically sampled and not 100% tested.
4
X9C102/103/104/503
D.C. OPERATING CHARACTERISTICS
(Over recommended operating conditions unless otherwise specified.)
Limits
Symbol
I
CC
I
SB
I
LI
V
IH
V
IL
C
IN(2)
Parameter
V
CC
Active Current
Standby Supply Current
CS, INC, U/D Input
Leakage Current
CS, INC, U/D Input HIGH
Voltage
CS, INC, U/D Input LOW
Voltage
CS, INC, U/D Input
Capacitance
Min.
Typ.
(4)
1
200
Max.
3
500
±10
Units
mA
µA
µA
V
V
pF
Test Conditions
CS = V
IL
, U/D = V
IL
or V
IH
and
INC = 0.4V to 2.4V @ max. t
CYC
CS = V
CC
– 0.3V, U/D and INC = V
SS
or V
CC
– 0.3V
V
IN
= V
SS
to V
CC
2
–1
V
CC
+ 1
0.8
10
V
CC
= 5V, V
IN
= V
SS
, T
A
= 25°C, f = 1MHz
ENDURANCE AND DATA RETENTION
Parameter
Minimum Endurance
Data Retention
Min.
100,000
100
Units
Data Changes per Bit
Years
Test Circuit #1
VR/RH
Test Circuit #2
V
H
/R
H
TEST POINT
RH
Test Circuit #3
RTOTAL
RL
CH
CW
25pF
RW
CL
10pF
V
S
TEST POINT
V
W
/R
W
V
L
/R
L
V
W
/R
W
FORCE
CURRENT
V
L
/R
L
10pF
5
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