A
PPLICATION
N
OTE
A V A I L A B L E
AN99 • AN115 • AN120 • AN124 • AN133 • AN134
Low Noise, Low Power, Low Cost
X9116
Digitally Controlled Potentiometer (XDCP
™
)
FEATURES
•
•
•
•
•
•
•
•
Solid-state nonvolatile
16 wiper taps
3-wire up/down serial interface
V
CC
= 2.7V and 5V
Active current < 50µA max.
Standby current < 1µA max.
R
TOTAL
= 10K
Ω
Packages: MSOP-8, SOIC
DESCRIPTION
The Xicor X9116 is a digitally controlled nonvolatile
potentiometer designed to be used in trimmer applica-
tions. The pot consists of 15 equal resistor segments
that connect to the wiper pin through programmable
CMOS switches. The tap position is programmed
through a 3-wire up/down serial port. The last position
of the wiper is stored in a nonvolatile memory location
which is recalled at the time of power up of the device.
The wiper moves through sequential tap positions with
inputs on the serial port. A falling edge on INC (bar)
causes the tap position to increment one position up or
down based on whether the U/D (bar) pin is held high
or low.
The X9116 can be used in many applications requiring
a variable resistance. In many cases it can replace a
mechanical trimmer and offers many advantages such
as temperature and time stability as well as the reli-
ability of a solid state solution.
BLOCK DIAGRAM
V
CC
(Supply Voltage)
Up/Down
(U/D)
Increment
(INC)
Device Select
(CS)
Control
and
Memory
R
H
/V
H
R
W
/V
W
R
L
/V
L
V
SS
(Ground)
General
R
H
13
*
3
2
1
R
L
0
R
W
-R
L
Resistance
15
14
10kΩ
9.34kΩ
8.68kΩ
* kΩ
2.08kΩ
1.42kΩ
760Ω
100Ω
REV 1.2 2/5/03
www.xicor.com
Characteristics subject to change without notice.
1 of 11
X9116
PIN DESCRIPTIONS
V
H
/R
H
and V
L
/R
L
The high (V
H
/R
H
) and low (V
L
/R
L
) terminals of the
X9116 are equivalent to the fixed terminals of a
mechanical potentiometer. The minimum voltage is
V
SS
and the maximum is V
CC
.
V
W
/R
W
R
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 200
Ω
to 400
Ω
depending upon V
CC
.
Up/Down (U/D)
The U/D input controls the direction of the wiper move-
ment and whether the counter is incremented (up) or
decremented (down).
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 X9116
will be placed in the low power standby mode until the
device is selected once again.
PIN CONFIGURATION
SOIC/MSOP
INC
U/D
V
H
/R
H
V
SS
1
2
3
4
X9116
8
7
6
5
V
CC
CS
V
L
/R
L
V
W
/R
W
PIN NAMES
Symbol
V
H
/R
H
V
W
/R
W
V
L
/R
L
V
SS
V
CC
U/D
INC
CS
Description
High Terminal
Wiper Terminal
Low Terminal
Ground
Supply Voltage
Up/Down Control Input
Increment Control Input
Chip Select Input
PRINCIPLES OF OPERATION
There are three sections of the X9116: 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 15 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 pin.
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 tem-
porarily be reduced by a significant amount if the wiper
is moved several positions.
When the device is powered-down, the last wiper posi-
tion stored will be maintained in the nonvolatile mem-
ory. When power is restored, the contents of the
memory are recalled and the wiper is set to the value
last stored.
REV 1.2 2/5/03
www.xicor.com
Characteristics subject to change without notice.
2 of 11
X9116
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 four bit counter. The output of this
counter is decoded to select one of 16 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 X9116, move the wiper,
and deselect the device without having to store the lat-
est 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 sys-
tem or until a power-up/down cycle recalls the previ-
ously 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 pref-
erence, system parameter changes due to tempera-
ture 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
REV 1.2 2/5/03
www.xicor.com
Characteristics subject to change without notice.
3 of 11
X9116
ABSOLUTE MAXIMUM RATINGS
Temperature under bias ....................–65
°
C to +135
°
C
Storage temperature .........................–65°C to +150°C
Voltage on CS, INC, U/D, V
H
/R
H
, V
L
/R
L
and V
CC
with respect to V
SS
................... –1V to +7V
∆
V = |V
H
/R
H
–V
L
/R
L
| ............................................ 5.5V
Lead temperature (soldering 10 seconds)..........300°C
I
W
(10 seconds) ............................................ ±10.0mA
COMMENT
Stresses above those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device.
This is a stress rating only; the functional operation of
the device (at these or any other conditions above
those listed in the operational sections of this specifi-
cation) is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect
device reliability.
RECOMMENDED OPERATING CONDITIONS
Temperature
Commercial
Industrial
Min.
0°C
–40°C
Max.
+70°C
+85°C
Supply Voltage (V
CC
)
X9116
X9116-2.7
Limits
5V ±10%
2.7V to 5.5V
POTENTIOMETER CHARACTERISTICS
(Over recommended operating conditions unless otherwise stated)
Limits
Symbol
R
TOTAL
V
VH
V
VL
R
W
R
W
I
W
Parameter
End to end resistance variation
V
H
/R
H
terminal voltage
V
L
/R
L
terminal voltage
Power rating
Wiper resistance
Wiper resistance
Wiper current
Noise
Resolution
Absolute linearity
(1)
Relative linearity
(2)
R
TOTAL
temperature coefficient
Ratiometric temperature coefficient
Min.
–20
V
SS
V
SS
Typ.
Max.
+20
V
CC
V
CC
10
Unit
%
V
V
mW
Ω
Ω
mA
Test Conditions/Notes
V
SS
=
0V
V
SS
=
0V
R
TOTAL
=
10 KΩ
I
W
= 1mA, V
CC
= 5V
I
W
= 1mA, V
CC
= 2.7V
200
400
-5.0
-120
6
-1
-0.2
±300
400
1000
+5.0
dBV√Hz Ref: 1kHz
%
+1
+0.2
±20
MI
(3)
MI
(3)
ppm/°C
ppm/°C
pF
See Circuit #3
V
w(n)(actual)
–V
w(n)(expected)
V
w(n+1)
–[V
w(n)+MI
]
C
H
/C
L
/C
W
Potentiometer capacitances
10/10/25
Notes:
(1) Absolute linearity is utilized to determine actual wiper voltage versus expected voltage = (V
w(n)
(actual)–V
w(n)
(expected)) = ±1
Ml Maximum.
(2) Relative linearity is a measure of the error in step size between taps = V
W(n+1)
–[V
w(n)
+ Ml] = ±0.2 Ml.
(3) 1 Ml = Minimum Increment = R
TOT
/15.
REV 1.2 2/5/03
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Characteristics subject to change without notice.
4 of 11
X9116
D.C. OPERATING CHARACTERISTICS
(Over recommended operating conditions unless otherwise specified)
Limits
Symbol
I
CC1
I
CC2
I
SB
I
LI
V
IH
V
IL
C
IN(5)
Parameter
V
CC
active current (Increment)
V
CC
active current (Store)
(EEPROM Store)
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)
Max.
150
400
1
±10
Unit
µA
µA
µA
µA
V
V
pF
Test Conditions
CS = V
IL
, U/D = V
IL
or V
IH
and
INC = 0.4V/2.4V @ max. t
CYC
CS = V
IH
, U/D = V
IL
or V
IH
and
INC = V
IH
@ max. t
WR
CS = V
CC
–0.3V, U/D and
INC = V
SS
or V
CC
–0.3V
V
IN
= V
SS
to V
CC
2V
–0.5
V
CC
+ 0.5
0.8
10
V
CC
= 5V, V
IN
= V
SS
,
T
A
= 25°C, f = 1MHz
Notes:
(4) Typical values are for T
A
= 25°C and nominal supply voltage.
(5) This parameter is periodically sampled and not 100% tested.
ENDURANCE AND DATA RETENTION
Parameter
Minimum endurance
Data retention
Min.
100,000
100
Unit
Data changes per bit
Years
Test Circuit #1
V
H
/R
H
Test Circuit #2
V
H
/R
H
Circuit #3 SPICE Macro Model
R
TOTAL
R
H
Test Point
C
H
10pF
R
W
C
W
25pF
C
L
10pF
R
L
V
S
Test Point
V
W
/R
W
V
L
/R
L
V
W
/R
W
VW
V
L
/R
L
L
Force
Current
A.C. CONDITIONS OF TEST
Input pulse levels
Input rise and fall times
Input reference levels
0V to 3V
10ns
1.5V
REV 1.2 2/5/03
www.xicor.com
Characteristics subject to change without notice.
5 of 11
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