X9C303.pdf

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X9C303.FM
A
PPLICATION
N
OTE
A V A I L A B L E
AN42 ¤ AN44Â48 ¤ AN50 ¤ AN52 ¤ AN53 ¤ AN71 ¤ AN92
Terminal Voltage ®5V, 100 Taps, Log Taper
X9C303
Digitally Controlled (EEPOT) Potentiometer
FEATURES
DESCRIPTION
¤ Solid-State Potentiometer
¤ Three-Wire Serial Interface
¤ 100 Wiper Tap Points
ÃWiper Position Stored in Nonvolatile Memory
and Recalled on Power-up
¤ 99 Resistive Elements, Log Taper
ÃTemperature Compensated
ÃEnd to End Resistance, ®15%
ÃTerminal Voltages, ®5V
¤ Low Power CMOS
ÃV
The Xicor X9C303 is a digitally-controlled (DCP)
potentiometer. The device consists of a resistor array,
wiper switches, a control section, and nonvolatile
(EEPOT) memory. The wiper position is controlled by a
three-wire interface.
= 5V
ÃActive Current, 3mA Max.
ÃStandby Current, 500°A Max.
¤ High Reliability
ÃEndurance, 100,000 Data Changes per Bit
ÃRegister Data Retention, 100 Years
¤ X9C303, 32 k
¤ Packages
Ã8 Lead TSSOP
Ã8 Lead SOIC
Ã8 Pin DIP
CC
The resistor array is composed of 99 resistive elements.
Between each element and at either end are tap points
accessible to the wiper termin al. T he po sition of th e 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 flexibility of computer-based
digital controls, and (3) the use of nonvolatile memory for
potentiometer settings retention.
FUNCTIONAL DIAGRAM
U/D
I NC
CS
7-BIT
UP/DOWN
COUNTER
99
R H/ V H
98
97
7-BIT
NONVOLATILE
MEMORY
ONE
OF
96
ONE-
HUNDRED
DECODER
TRANSFER
GATES
RESISTOR
ARRAY
2
STORE AND
RECALL
CONTROL
CIRCUITRY
1
V CC
0
V SS
R L/ V L
R W/ V W
E
POT© is a trademark of Xicor, Inc.
draft-1.0 2/24/99 T0/C0/D0
1
Characteristics subject to change without notice
2
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X9C303
PIN DESCRIPTIONS
PIN NAMES
V
H
and V
L
Symbol
Description
) terminals of the device are
equivalent to the fixed terminals of a mechanical
potentiometer. The minimum voltage is Â5V and the
maximum is +5V. It should be noted that the terminology
of V
H
) and low (V
L
V
H
High Terminal (Potentiometer)
V
W
Wiper Terminal (Potentiometer)
references the relative position of the
terminal i n r elation to wiper movement direction selected
by the U/D input and not the voltage potential on the
terminal.
and V
V
L
Low Terminal (Potentiometer)
L
H
V
SS
Ground
V
C C
Supply Voltage
V
U/D
Up/Down Control Input
W
I NC
Increment Control Input
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.
W
CS
Chip Select Control Input
NC
No Connection
Up/Do wn (U/D)
POTENTIOMETER RELATIONSHIPS
The U/D input controls the direction of the wiper
movement and whether the counter is incremented or
decremented.
S100
V H
(V S )
Incr eme nt (INC)
R99
S99
input is negative-edge triggered. Toggling INC
will move the wiper and either increment or decrement
the c oun ter in the direction indicated by the logic level on
the U/D input.
INC
R98
S98
V W
Chip Select (CS)
S3
The device is selected when the CS input is LOW. The
curren t co unter value is stored in no nvol atile 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.
R2
S2
R1
S1
V L
PIN CONFIGURATION
G i
=
20 Log R 1
++ +
R TOTAL
. . . R i
=
V W
V S
(
V L 0 V
=
)
--------------------------------------------
--------
R 1 R 2 . . . R 99
++ + K W
@
=
R TOTAL
DIP/SOIC/(TSSOP)
(Refer Test Circuit 1)
(CS)
( V CC )
(IN C )
(U/D)
INC
U/D
V H
V SS
1
2
3
4
X9C303
8
7
6
5
V CC
CS
V L
V W
(V L )
(V W )
(V SS )
(V H )
2
The high (V
V
The
R 2
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X9C303
PRINCIPLES OF OPERATION
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 reac hed , 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.
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.
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 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 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.
The electronic switches on the device operate in a Ämake
before breakÅ mode when the wiper changes tap
positions. If the wiper is moved several positi ons, multiple
taps are connected to the wiper for t
MODE SELECTION
CS
INC U/D
Mode
IW
(INC to V
W
L
H
Wiper Up
value for the device can
temporarily be reduced by a significant amount if the
wiper is moved several positions.
TOTAL
L
L
Wiper Down
H
X
Store Wiper Position
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.
H
X
X
Standby Current
L
X
No Store, Return to Standby
SYMBOL TABLE
Inst ruct ion s and Pr ogramming
WAVEFORM
INPUTS
OUTPUTS
The INC, U/D and CS inputs control th e m ovement of the
wiper along the resistor array. With CS set LOW t he
devi ce is selected and enabled to respond to the U/D
and INC inputs. HIGH to LOW transitions on INC will
in cre ment 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.
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
DonÇt Care:
Changes
Allowed
Changing:
State Not
Known
The value of t he counter is stored in nonvol atile memory
whenever CS transistions HIGH while the INC input is
also HIGH.
N/A
Center Line
is High
Impedance
3
change). The R
104214099.007.png 104214099.008.png 104214099.009.png
X9C303
ABSOLUTE MAXIMUM RATINGS*
*COMMENT
Temperature under Bias .........................Â65 C to +135 C
Storage Te mperatur e... ... ........................Â65 C to +150 C
Voltage on CS, INC, U/D and V
CC
Stresses above those listed under ÄAbsolute Maximum
RatingsÅ 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.
with Respect to V
...................................... Â1V to +7V
SS
Voltage on V
and V
H
L
Referenced to V
........................................ Â8V to +8V
SS
|
X9C303 .................................................................... 10V
Lead Temperature (Soldering, 10 seconds) ......... +300 C
Wiper Current ...........................................................®1mA
ÂV
H
L
ANALOG CHARACTERISTICS
Electrical Characteristics
Temperature Coefficient
End-to-End Resistance Tolerance .......................... ®15%
Power Rating at 25 C
X9C303 ................................................................10mW
Wiper Current ..................................................®1mA Max.
Typical Wiper Resistance .............................. . 40 at 1mA
Typical Resistor Noise ............23 nV (RMS)/
(Â40 C to +85 C)
X9C303 ........................................... ®400 ppm/ C Typical
Ratiometric Temperature Coefficient ..................®20 ppm
Wiper Adjustability
Hz at 1 KHz
Typical Charge Pump Noise.....20 mV (RMS) @ 2.5 MHz
´
Unlimited Wiper Adjustment (Non-Store operation)
Wiper Position Store
Operations.........................100,000 Data Changes per Bit
Relative Variation
Relative variation is a measure of the error in step size
between taps = log(V
Physical Characteristics
w(n)
) Â log(V
w(n-1)
) = 0.045®0.003
Marking Includes
ManufacturerÇs Trademark
Resistance Value or Code
Date Code
for tap n = 2 Â 99
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%
R(V H -V W )
R(V W -V L )
Tap
4
V = |V
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X9C303
Test Circuit #1
Test Circuit #2
Circuit #3 SPICE Macromodel
V H
V H
R H
R TOTAL
R L
TEST POINT
C L
10pF
C H
C W
V S
TEST POINT
V W
V W
FORCE
CURRENT
10pF
25pF
V L
V L
R W
RECOMMENDED OPERATING CONDITIONS
Temperature
Min.
Max.
Supply Voltage
Limits
Commercial
0 C
+70 C
X9C303
5V ®10%
Industrial
Â40 C
+85 C
Military
Â55 C
+125 C
D.C. OPERATING CHARACTERISTICS
(Over recommended operating conditions unless otherwise specified.)
Limits
Symbol
Parameter
Min.
Typ.
(1)
Max.
Units
Test C onditions
I
CC
V
CC
Active Current
1
3
mA
and
INC = 0.4V to 2.4V @ max. t
IL
, U/D = V
IL
or V
IH
CY C
I
SB
Standby Supply Current
200
500
°A
CS = V
CC
 0.3V, U/D and INC =
V
SS or V CC Â 0.3V
I LI
CS, INC, U/D Input
Leakage C ur rent
®10
°A
V IN = V SS to V CC
V IH
CS, INC, U/D Input HIGH
Vol t age
2
V CC + 1
V
V IL
CS, INC, U/D Input LOW
Voltage
Â1
0.8
V
R W
Wiper Resistance
40
100
Max. Wiper Current ®1mA
V H
V H Terminal Voltage
Â5
+5
V
V L
V L Terminal Voltage
Â5
+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
STANDARD PARTS
Part Number
Maximum Resistance
Wiper Increments
Minimum Resistance
X9C303
32K
Log Taper
40 Typical
Notes:
(1) Typical values are for T
= 25 C and nominal supply voltage.
(2) This parameter is periodically sampled and not 100% tested.
A
5
CS = V
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