XICOR X9C303

APPLICATION NOTE
A V A I L A B L E
AN42 • AN44–48 • AN50 • AN52 • AN53 • AN71 • AN92
Terminal Voltage ±5V, 100 Taps, Log Taper
X9C303
Digitally Controlled Potentiometer (XDCP™)
FEATURES
DESCRIPTION
• 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, log taper
—Temperature compensated
—End to end resistance, ±15%
—Terminal voltages, ±5V
• Low power CMOS
—VCC = 5V
—Active current, 3mA max.
—Standby current, 750µA max.
• High reliability
—Endurance, 100,000 data changes per bit
—Register data retention, 100 years
• X9C303, 32 kΩ
• Packages
—8-lead TSSOP
—8-lead SOIC
—8-pin DIP
The Xicor X9C303 is a digitally controlled potentiometer (XDCP). The device consists of a resistor array,
wiper switches, a control section, and nonvolatile
memory. The wiper position is controlled by a threewire 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. Digitallycontrolled 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.
BLOCK DIAGRAM
U/D
INC
CS
7-Bit
Up/Down
Counter
99
RH/VH
98
97
7-Bit
Nonvolatile
Memory
96
One
of
OneHundred
Decoder
Transfer
Gates
Resistor
Array
2
VCC
VSS
Store and
Recall
Control
Circuitry
1
0
RL/VL
RW/VW
XDCP™ is a trademark of Xicor, Inc.
REV 1.1 4/27/01
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Characteristics subject to change without notice.
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X9C303
PIN DESCRIPTIONS
PIN NAMES
VH and VL
The high (VH) and low (VL) terminals of the device are
equivalent to the fixed terminals of a mechanical
potentiometer. The minimum voltage is –5V and the
maximum is +5V. It should be noted that the terminology of VL and VH 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.
Symbol
VW
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.
Description
VH
High Terminal (Potentiometer)
VW
Wiper Terminal (Potentiometer)
VL
Low Terminal (Potentiometer)
VSS
Ground
VCC
Supply Voltage
U/D
Up/Down Control Input
INC
Increment Control Input
CS
Chip Select Control Input
NC
No Connection
POTENTIOMETER RELATIONSHIPS
Up/Down (U/D)
The U/D input controls the direction of the wiper movement and whether the counter is incriminated or decremented.
S100
VH
(VS)
S99
R98
S98
VW
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.
R99
S3
R2
S2
R1
S1
VL
R1 + R2 + . . . + Ri
VW
G i = 20Log ------------------------------------------------- = --------- ( V L = 0V )
R TOTAL
VS
R 1 + R 2 + . . . + R 99 @ 33KΩ = R TOTAL
(Refer Test Circuit 1)
PIN CONFIGURATION
DIP/SOIC/(TSSOP)
(CS) INC
1
(VCC) U/D
2
(INC) VH
(U/D) V
SS
3
REV 1.1 4/27/01
4
X9C303
8
VCC (VL)
7
CS (VW)
6
VL
5
VW (VH)
(VSS)
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Characteristics subject to change without notice.
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X9C303
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 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 tIW (INC to
VW change). The RTOTAL 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 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 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
CS
U/D
Mode
L
H
Wiper Up
L
L
Wiper Down
H
H
X
Store Wiper Position
X
X
Standby Current
L
X
No Store, Return to Standby
SYMBOL TABLE
WAVEFORM
The value of the counter is stored in nonvolatile memory whenever CS transitions HIGH while the INC input
is also HIGH.
REV 1.1 4/27/01
INC
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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
Don’t Care:
Changes
Allowed
N/A
Changing:
State Not
Known
Center Line
is High
Impedance
Characteristics subject to change without notice.
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X9C303
Typical wiper resistance ...........................40Ω at 1mA
Typical resistor
noise ........................ 23 nV (RMS)/÷Hz at 1kHzPHZ
Typical charge pump noise.. 20 mV (RMS) @ 2.5 MHz
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 VCC
with respect to VSS .................................. –1V to +7V
Voltage on VH and VL
referenced to VSS ................................... –8V to +8V
∆V = |VH–VL| X9C303 .......................................... 10V
Lead temperature (soldering, 10 seconds)...... +300°C
Wiper current ..................................................... ±1mA
Relative Variation
Relative variation is a measure of the error in step size
between taps = log (Vw(n)) – log (Vw(n-1)) = 0.045 ± 0.003
for tap n = 2 – 99
Temperature Coefficient
(–40°C to +85°C) X9C303 .......... ±400 ppm/°C Typical
Ratiometric temperature coefficient ..............±20 ppm
COMMENT
Stresses above those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device.
This is a stress rating only; 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.
Wiper Adjustability
Unlimited Wiper Adjustment (Non-Store operation)
Wiper Position Store
Operations ...................100,000 Data Changes per Bit
Physical Characteristics
Marking Includes
ANALOG CHARACTERISTICS
Manufacturer’s Trademark
Electrical Characteristics
End-to-end resistance tolerance ....................... ±15%
Power rating at 25°C X9C303 ........................... 10mW
Wiper current ............................................ ±1mA Max.
Resistance Value or Code
Date Code
Typical Electrical Taper
100.0%
90.0%
80.0%
% Total Resistance
70.0%
60.0%
50.0%
40.0%
30.0%
20.0%
10.0%
REV 1.1 4/27/01
99
96
93
90
87
84
81
78
75
72
69
66
63
60
57
54
51
48
45
42
39
36
33
30
27
24
21
18
15
9
6
12
R(VH–VW)
R(VW–VL)
3
0
0.0%
Tap
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Characteristics subject to change without notice.
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X9C303
Test Circuit #1
Test Circuit #2
Circuit #3SPICE Macro Model
VH
VH
RTOTAL
RH
Test Point
VS
Test Point
VW
VW
Force
Current
VL
VL
CH
CW
10pF
25pF
CL
RL
10pF
RW
RECOMMENDED OPERATING CONDITIONS
Temperature
Min.
Max.
Supply Voltage
Limits
Commercial
0°C
+70°C
X9C303
5V ±10%
Industrial
–40°C
+85°C
Military
–55°C
+125°C
D.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified.)
Limits
Symbol
Parameter
Min.
Typ.1
Max.
Unit
Test Conditions
1
3
mA
CS = VIL, U/D = VIL or VIH and
INC = 0.4V to 2.4V @ max. tCYC
200
750
µA
CS = VCC – 0.3V, U/D and INC
= VSS or VCC – 0.3V
±10
µA
VIN = VSS to VCC
ICC
VCC active current
ISB
Standby supply current
ILI
CS, INC, U/D input leakage
current
VIH
CS, INC, U/D input HIGH
voltage
2
VCC + 1
V
VIL
CS, INC, U/D input LOW
voltage
–1
0.8
V
RW
Wiper resistance
100
Ω
VH
VH terminal voltage
–5
+5
V
VL
VL terminal voltage
–5
+5
V
10
pF
VCC = 5V, VIN = VSS,
TA = 25°C, f = 1MHz
pF
See Circuit 3
CIN(2)
40
CS, INC, U/D input capacitance
CH/CL/CW
Potentiometer capacitance
10/10/25
Max. Wiper Current ±1mA
Standard Parts
Part Number
Maximum Resistance
Wiper Increments
Minimum Resistance
X9C303
32KΩ
Log Taper
40Ω Typical
Notes: (1) Typical values are for TA = 25°C and nominal supply voltage.
(2) This parameter is periodically sampled and not 100% tested.
REV 1.1 4/27/01
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Characteristics subject to change without notice.
5 of 10
X9C303
A.C. CONDITIONS OF TEST
Input pulse levels
0V to 3V
Input rise and fall times
10ns
Input reference levels
1.5V
A.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified)
Limits
Symbol
Parameter
Typ.3
Min.
Max.
Unit
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
tR, tF4
INC input rise and fall time
500
ns
Power up to wiper stable
500
µs
50
mV/µs
tPU4
tR VCC4
4
VCC power-up rate
µs
0.2
A.C. TIMING
CS
tCYC
tCI
tIL
tIC
tIH
tCPH
90% 90%
10%
INC
tID
tDI
tF
tR
U/D
tIW
VW
MI
(8)
Notes: (3) Typical values are for TA = 25°C and nominal supply voltage.
(4) This parameter is periodically sampled and not 100% tested.
(5) MI in the A.C. timing diagram refers to the minimum incremental change in the VW output due to a change in the wiper position.
REV 1.1 4/27/01
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Characteristics subject to change without notice.
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X9C303
PACKAGING INFORMATION
8-Lead Plastic Dual In-Line Package Type P
0.430 (10.92)
0.360 (9.14)
0.260 (6.60)
0.240 (6.10)
Pin 1 Index
Pin 1
0.300
(7.62) Ref.
Half Shoulder Width On
All End Pins Optional
0.145 (3.68)
0.128 (3.25)
Seating
Plane
0.025 (0.64)
0.015 (0.38)
0.065 (1.65)
0.045 (1.14)
0.150 (3.81)
0.125 (3.18)
0.110 (2.79)
0.090 (2.29)
.073 (1.84)
Max.
0.060 (1.52)
0.020 (0.51)
0.020 (0.51)
0.016 (0.41)
0.325 (8.25)
0.300 (7.62)
0°
15°
Typ. 0.010 (0.25)
NOTE:
1. ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
2. PACKAGE DIMENSIONS EXCLUDE MOLDING FLASH
REV 1.1 4/27/01
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Characteristics subject to change without notice.
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X9C303
PACKAGING INFORMATION
8-Lead Plastic Small Outline Gull Wing Package Type S
0.150 (3.80) 0.228 (5.80)
0.158 (4.00) 0.244 (6.20)
Pin 1 Index
Pin 1
0.014 (0.35)
0.019 (0.49)
0.188 (4.78)
0.197 (5.00)
(4X) 7°
0.053 (1.35)
0.069 (1.75)
0.004 (0.19)
0.010 (0.25)
0.050 (1.27)
0.010 (0.25)
X 45°
0.020 (0.50)
0.050" Typical
0.050"
Typical
0° - 8°
0.0075 (0.19)
0.010 (0.25)
0.250"
0.016 (0.410)
0.037 (0.937)
0.030"
Typical
8 Places
FOOTPRINT
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
REV 1.1 4/27/01
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Characteristics subject to change without notice.
8 of 10
X9C303
PACKAGING INFORMATION
8-Lead Plastic, TSSOP, Package Type V
.025 (.65) BSC
.169 (4.3)
.252 (6.4) BSC
.177 (4.5)
.114 (2.9)
.122 (3.1)
.047 (1.20)
.0075 (.19)
.0118 (.30)
.002 (.05)
.006 (.15)
.010 (.25)
Gage Plane
0° – 8°
Seating Plane
.019 (.50)
.029 (.75)
(4.16) (7.72)
Detail A (20X)
(1.78)
.031 (.80)
.041 (1.05)
(0.42)
(0.65)
All Measurements Are Typical
See Detail “A”
NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS)
REV 1.1 4/27/01
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Characteristics subject to change without notice.
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X9C303
Ordering Information
X9C303
X
X
Temperature Range
Blank = Commercial = 0°C to +70°C
I = Industrial = –40°C to +85°C
Package
P = 8-Lead Plastic DIP
S8 = 8-Lead SOIC
V8 = 8-Lead TSSOP
LIMITED WARRANTY
©Xicor, Inc. 2001 Patents Pending
Devices sold by Xicor, Inc. are covered by the warranty and patent indemnification 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 fitness for any purpose. Xicor, Inc. reserves the right to discontinue production and change specifications 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, or licenses are implied.
COPYRIGHTS AND TRADEMARKS
Xicor, Inc., the Xicor logo, E2POT, XDCP, XBGA, AUTOSTORE, Direct Write cell, Concurrent Read-Write, PASS, MPS, PushPOT, Block Lock, IdentiPROM,
E2KEY, X24C16, SecureFlash, and SerialFlash are all trademarks or registered trademarks of Xicor, Inc. All other brand and product names mentioned herein are
used for identification purposes only, and are trademarks or registered trademarks of their respective holders.
U.S. PATENTS
Xicor products are covered by one or more of the following U.S. Patents: 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; 4,980,859; 5,012,132; 5,003,197; 5,023,694; 5,084,667; 5,153,880; 5,153,691;
5,161,137; 5,219,774; 5,270,927; 5,324,676; 5,434,396; 5,544,103; 5,587,573; 5,835,409; 5,977,585. 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 occurrence.
Xicor’s 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 significant 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.
REV 1.1 4/27/01
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Characteristics subject to change without notice.
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