A
PPLICATION
N
OTES
A V A I L A B L E
AN42 • AN44–48 • AN50 • AN52 • AN53 • AN71 • AN73
Terminal Voltage
±
5V, 32 Taps
X9313
X9313
E
2
POT™ Nonvolatile Digital Potentiometer
FEATURES
DESCRIPTION
The Xicor X9313 is a solid state nonvolatile potentiom-
eter and is ideal for digitally controlled resistance
trimming.
The X9313 is a resistor array composed of 31 resistive
elements. Between each element and at either end are
tap points accessible to the wiper element. 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 nonvola-
tile memory and then be recalled upon a subsequent
power-up operation.
The resolution of the X9313 is equal to the maximum
resistance value divided by 31. As an example, for the
X9313W (10KΩ) each tap point represents 323Ω.
All Xicor nonvolatile memories are designed and tested
for applications requiring extended endurance and data
retention.
•
•
•
•
•
•
•
Low Power CMOS
—V
CC
= 3V to 5.5V
—Active Current, 3mA Max
—Standby Current, 500
µ
A Max
31 Resistive Elements
—Temperature Compensated
—
±
20% End to End Resistance Range
— –5V to +5V Range
32 Wiper Tap Points
—Wiper Positioned via Three-Wire Interface
—Similar to TTL Up/Down Counter
—Wiper Position Stored in Nonvolatile
Memory and Recalled on Power-Up
100 Year Wiper Position Data Retention
X9313Z = 1K
Ω
X9313W = 10K
Ω
Packages
—8-Lead MSOP
—8-Lead PDIP
—8-Lead SOIC
FUNCTIONAL DIAGRAM
U/D
INC
CS
5-BIT
UP/DOWN
COUNTER
31
30
29
VH
5-BIT
NONVOLATILE
MEMORY
ONE
OF
THIRTY-
TWO
DECODER
28
TRANSFER
GATES
2
RESISTOR
ARRAY
VCC
GND
STORE AND
RECALL
CONTROL
CIRCUITRY
1
0
VL
VW
3866 FHD F01
E
2
POT™ is a trademark of Xicor, Inc.
©Xicor, Inc. 1994, 1995, 1996 Patents Pending
3866-1.5 6/12/96 T5/C1/D8 NS
1
Characteristics subject to change without notice
X9313
PIN DESCRIPTIONS
V
H
and V
L
The high (V
H
) and low (V
L
) terminals of the X9313 are
equivalent to the fixed terminals of a mechanical potenti-
ometer. The minimum voltage is –5V 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
Vw 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 40Ω.
Up/Down (U/D)
The U/D input controls the direction of the wiper move-
ment 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 X9313
will be placed in the low power standby mode until the
device is selected once again.
PIN NAMES
Symbol
V
H
V
W
V
L
V
SS
V
CC
U/D
INC
CS
Description
High Terminal
Wiper Terminal
Low Terminal
Ground
Supply Voltage
Up/Down Input
Increment Input
Chip Select Input
3866 PGM T01
PIN CONFIGURATION
8-LEAD DIP/SOIC
INC
U/D
VH
VSS
1
2
3
4
X9313
8
7
6
5
VCC
CS
VL
VW
8-LEAD MSOP
VH
VSS
VW
VL
1
2
3
4
X9313
8
7
6
5
U/D
INC
VCC
CS
3866 ILL F02.2
2
X9313
DEVICE OPERATION
There are three sections of the X9313: 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 31 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
INC,
U/D and
CS
inputs control the movement of the
wiper along the resistor array. With
CS
set LOW the
X9313 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 thirty two wiper positions
along the resistive array.
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 value of the counter is stored in nonvolatile memory
whenever
CS
transistions HIGH while the
INC
input is
also HIGH.
When the X9313 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.
Operation Notes
The system may select the X9313, move the wiper and
deselect the device without having to store the latest
wiper position in nonvolatile memory. The wiper move-
ment 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-up/down 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 X9313
and then move the wiper up and down until the proper
trim is attained.
T
IW
/R
TOTAL
The electronic switches on the X9313 operate in a
“make before break” mode when the wiper changes tap
positions. If the wiper is moved several positions mul-
tiple taps are connected to the wiper for t
IW
(INC to V
W
change). The R
TOTAL
value for the device can tempo-
rarily be reduced by a significant amount if the wiper is
moved several positions.
R
TOTAL
with V
CC
Removed
The end to end resistance of the array will fluctuate once
V
CC
is removed.
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
X9313
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
∆V
= |V
H
–V
L
|
X9313Z ............................................................. 4V
X9313W, X9313U, X9313T ............................ 10V
Lead Temperature (Soldering 10 seconds)....... 300°C
Wiper Current .....................................................
±1mA
ANALOG CHARACTERISTICS
Electrical Characteristics
End-to-End Resistance Tolerance .....................
±20%
Power Rating at 25°C
X9313Z ....................................................... 16mW
X9313W ...................................................... 10mW
Wiper Current ............................................
±1mA
Max.
Typical Wiper Resistance ......................... 40Ω at 1mA
Typical Noise .......................... < –120dB/ Hz Ref: 1V
Resolution
Resistance ............................................................. 3%
Linearity
Absolute Linearity
(1) ........................................
±1.0
Ml
(2)
Relative Linearity
(3)
.....................................
±0.2
Ml
(2)
Test Circuit #1
Temperature Coefficient
(–40°C to +85°C)
X9313Z ....................................... +600 ppm/°C Typical
X9313W, X9313U, X9313T ........ +300 ppm/°C Typical
Ratiometric Temperature Coefficient ............
±20
ppm
Wiper Adjustability
Unlimited Wiper Adjustment (Non-Store operation)
Wiper Position Store Operations ............... 10,000
Data Changes
Physical Characteristics
Marking Includes
Manufacturer’s Trademark
Resistance Value or Code
Date Code
Test Circuit #2
*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 specifica-
tion is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect device
reliability.
VH
VH
TEST POINT
TEST POINT
VW
VL
3866 FHD F04
VW
VL
FORCE
CURRENT
3866 FHD F05
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) 1 Ml = Minimum Increment = R
TOT
/31.
(3) Relative Linearity is a measure of the error in step size between taps = V
W(n+1)
– [V
w(n)
+ Ml] = +0.2 Ml.
4
X9313
RECOMMENDED OPERATING CONDITIONS
Temperature
Commercial
Industrial
Military
Min.
0°C
–40°C
–55°C
Max.
+70°C
+85°C
+125°C
3866 PGM T03.1
Supply Voltage
X9313
X9313-3
Limits
5V
±10%
3V to 5.5V
3866 PGM T04.1
D.C. OPERATING CHARACTERISTICS
(Over recommended operating conditions unless otherwise specified.)
Limits
Symbol
I
CC
I
SB
I
LI
V
IH
V
IL
R
W
V
VH
V
VL
C
IN(5)
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
Wiper Resistence
VH Terminal Voltage
VL Terminal Voltage
CS, INC,
U/D Input
Capacitance
Min.
Typ.
(4)
1
200
Max.
3
500
±10
2
–1
40
–5
–5
V
CC
+ 1
0.8
100
+5
+5
10
Units
mA
µA
µA
V
V
Ω
V
V
pF
Max. Wiper Current
±1mA
Test Conditions
CS
= V
IL
, U/D = V
IL
or V
IH
and
INC
= 0.4V/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
V
CC
= 5V, V
IN
= V
SS
,
T
A
= 25°C, f = 1MHz
3866 PGM T05.3
STANDARD PARTS
Part Number
X9313Z
X9313W
X9313U
X9313T
Maximum Resistance
1KΩ
10KΩ
50KΩ
100KΩ
Wiper Increments
32.3Ω
323Ω
2381Ω
3226Ω
Minimum Resistance
40Ω
40Ω
40Ω
40Ω
3866 PGM T08.1
Notes:
(4) Typical values are for T
A
= 25°C and nominal supply voltage.
(5) This parameter is periodically sampled and not 100% tested.
5
Analogue and Mixed Signal
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