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Digitally Controlled Potentiometer (XDCP

)

X93154

FEATURES

· Solid-state potentiometer
· 3-wire serial interface
· 32 wiper tap points

--Wiper position stored in nonvolatile memory

and recalled on power-up

· 31 resistive elements

--Temperature compensated
--End to end resistance range ± 30%
--Terminal voltage, 0 to V

· Low power CMOS

--V

= 3V±10%

--Active current, 250µA max.
--Standby current, 1µA max.

· High reliability

--Endurance 20,000 data changes per bit
--Register data retention, 10 years

· R

TOTAL

value = 50K

· Packages

--8-lead MSOP, FCP

DESCRIPTION

The Xicor X93154 is a digitally controlled potentiome-
ter (XDCP). The device consists of a resistor array,
wiper switches, a control section, and nonvolatile
memory. The wiper position is controlled by a 3-wire
interface.

The potentiometer is implemented by a resistor array
composed of 31 resistive elements and a wiper switch-
ing network. The position of the wiper element is con-
trolled 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 opera-
tion.

The device is connected as a two-terminal variable
resistor and can be used in a wide variety of applica-
tions including:

bias and gain control

LCD Contrast Adjustment

PPLICATION

OTE

A V A I L A B L E

AN20 · AN4253 · AN71 · AN73 · AN88 · AN9192 · AN99 · AN115 · AN120 · AN124 · AN133 · AN134 · AN135

XDCP

is a trademark of Xicor, Inc.

Low Noise, Low Power, 32 Taps

BLOCK DIAGRAM

5-Bit

Up/Down

Counter

5-Bit

Nonvolatile

Memory

Store and

Recall

Control

Circuitry

One

Decoder

Resistor

Array

U/D
INC

Transfer

Gates

Thirty

Control

and

Memory

Up/Down

(U/D)

Increment

(INC)

Device Select

(CS)

(Supply Voltage)

(Ground)

General

Detailed

Two

30K

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X93154

PIN CONFIGURATION

X93154 ORDERING CODES

PIN DESCRIPTIONS

Ordering Number

RTOTAL

Package

Temperature Range

X93154UX8I-3

50Kohm

8-bump Flipchip package

-40°C to +85°C

X93154UM8I-3

50Kohm

8-lead MSOP package

-40°C to +85°C

MSOP

Symbol

Brief Description

INC

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.

U/D

Up/Down (U/D)

. The U/D input controls the direction of the wiper movement and whether the

counter is incremented or decremented.

. The R

and R

pins of the X93154 are equivalent to the fixed terminals of a

mechanical potentiometer. The minimum voltage is V

and the maximum is V

. The terminol-

ogy of R

and R

references the relative position of the terminal in relation to wiper movement

direction selected by the U/D input.

Ground

No Connection

. (or can be connected to any voltage between V

and V

. The R

and R

pins of the X93154 are equivalent to the fixed terminals of a

mechanical potentiometer. The minimum voltage is V

and the maximum is V

. The terminol-

ogy of R

and R

references the relative position of the terminal in relation to wiper movement

direction selected by 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 X93154 will be placed in the low power standby mode until
the device is selected once again.

Supply Voltage

INC

U/D

X93154

MSOP

NC can be left unconnected, or connected to any voltage between V

and V

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X93154

ABSOLUTE MAXIMUM RATINGS

Temperature under bias ....................65

C to +135

Storage temperature ........................ 65°C to +150°C
Voltage on CS, INC, U/D, R

, R

and V

with respect to V

..............................1V to +6.5V

Lead temperature (soldering 10 seconds)......... 300°C
Maximum resistor current..................................... 2mA

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

POTENTIOMETER CHARACTERISTICS

(Over recommended operating conditions unless otherwise stated.)

Notes:

(1) Absolute linearity is utilized to determine actual wiper voltage versus expected voltage = (V

H(n)

(actual)V

H(n)

(expected)) = ±1 Ml

Maximum. n = 1 .. 29 only

(2) Relative linearity is a measure of the error in step size between taps = V

H(n+1)

--[V

H(n)

+ Ml] = ±0.5 Ml, n = 1 .. 29 only.

(3) 1 Ml = Minimum Increment = R

TOT

/31.

(4) Typical values are for T

= 25°C and nominal supply voltage.

(5) This parameter is periodically sampled and not 100% tested
(6) Typical values are for T

= 25°C and nominal supply voltage.

(7) This parameter is not 100% tested.
(8) When performing multiple write operations, V

must not decrease by more than 150mV from its initial value.

Temperature

Min.

Max.

Industrial

40°C

+85°C

Supply Voltage (V

)

Limits

X9315

3V ±10%

(8)

Symbol

Parameter

Limits

Test Conditions/Notes

Min.

Typ.

Max.

Unit

TOT

End to end resistance

, R

terminal voltages

Power rating

(7)

TOTAL

50 K

Noise

-120

dBV

(7)

Ref: 1kHz

Wiper Resistance

1000

(5) (6)

Wiper Current

0.6

(5) (6)

Resolution

Absolute linearity

(1)

±1

(3)

H(n)(actual)

H(n)(expected)

Relative linearity

(2)

±0.5

(3)

H(n+1)

H(n)+MI

]

TOTAL

temperature coefficient

±100

ppm/°C

(7)

Potentiometer capacitances

10/10/25

(7)

See circuit #3

X93154

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D.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified.)

ENDURANCE AND DATA RETENTION

Test Circuit #1

Circuit #2 SPICE Macro Model

A.C. CONDITIONS OF TEST

Symbol

Parameter

Limits

Unit

Test Conditions

Min.

Typ.

(4)

Max.

CC1

active current (Increment)

250

µA

CS = V

, U/D = V

or V

and

INC = 0.4V @ max. t

CYC

CC2

active current (Store)

(EEPROM Store)

600

µA

CS = V

, U/D = V

or V

and

INC = V

@ max. t

Standby supply current

µA

CS = V

0.3V, U/D and

INC = V

or V

0.3V

±1

µA

= V

100

150

µA

= 3V, CS = 0

INC, U/D input leakage current

±1

µA

= V

to V

CS, INC, U/D input HIGH voltage

x 0.7

+ 0.5

CS, INC, U/D input LOW voltage

0.5

x 0.1

(5)(7)

CS, INC, U/D input capacitance

= 3V, V

= V

= 25°C, f = 1MHz

Parameter

Min.

Unit

Minimum endurance

20,000

Data changes per bit

Data retention

Years

Test Point

10pF

TOTAL

25pF

Input pulse levels

0V to 3V

Input rise and fall times

10ns

Input reference levels

1.5V

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X93154

A.C. OPERATING CHARACTERISTICS (Over recommended operating conditions unless otherwise specified)

POWER UP AND DOWN REQUIREMENTS

There are no restrictions on the power-up or power-down conditions of V

and the voltages applied to the potenti-

ometer pins provided that V

is always more positive than or equal to V

and V

, i.e., V

. The V

ramp

rate spec is always in effect.

A.C. TIMING

Symbol

Parameter

Limits

Unit

Min.

Typ.

(6)

Max.

CS to INC setup

100

INC HIGH to U/D change

100

U/D to INC setup

100

INC LOW period

µs

INC HIGH period

µs

INC Inactive to CS inactive

µs

CPH

CS Deselect time (NO STORE)

250

CPH

CS Deselect time (STORE)

CYC

INC cycle time

µs

(7)

INC input rise and fall time

500

µs

(7)

power-up rate

1.0

10,000

V/ms

Store cycle

INC

U/D

CYC

CPH

10%

90%

(Store)

X93154

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PIN DESCRIPTIONS

and R

The R

and R

pins of the X93154 are equivalent to

the fixed terminals of a mechanical potentiometer. The
minimum voltage is V

and the maximum is V

. The

terminology of R

and R

references the relative posi-

tion of the terminal in relation to wiper movement direc-
tion selected by the U/D input.

Up/Down (U/D)

The U/D input controls the direction of the wiper move-
ment and whether the counter is incremented or decre-
mented.

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
X93154 will be placed in the low power standby mode
until the device is selected once again.

PIN CONFIGURATION

PIN NAMES

PRINCIPLES OF OPERATION

There are three sections of the X93154: 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 comprised
of 31 individual resistors connected in series. At either
end of the array and between each resistor is an elec-
tronic switch that transfers the connection 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.

If the wiper is moved several positions, multiple taps
are connected to the wiper for t

(INC to V

change).

The 2-terminal resistance value for the device can tem-
porarily change 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.

INC

U/D

X93154

MSOP

NC = No Connect. Can be connected to any

voltage between V

and V

, or left unconnected.

Symbol

Description

High terminal

Low terminal

Ground

Supply voltage

U/D

Up/Down control input

INC

Increment control input

Chip Select control input

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X93154

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 five bit counter. The output of this counter
is decoded to select one of thirty two 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. In order to avoid an accidental store dur-
ing power-up, CS must go HIGH with V

during initial

power-up. When performing multiple write operations,
V

must not decrease by more than 150mV from its

initial value. When left open, the CS pin is internally
pulled up to V

by an internal 30K resistor.

The system may select the X93154, 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 system
or until a power-up/down cycle recalled the previously
stored data. In order to recall the stored position of the
wiper on power-up, the CS pin must be held HIGH.

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 prefer-
ence, system parameter changes due to temperature
drift, or other system trim requirements.

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

SYMBOL TABLE

INC

U/D

Mode

Wiper Up

Wiper Down

Store Wiper Position

Standby Current

No Store, Return to Standby

Wiper Up (not recommended)

Wiper Down (not recommended)

WAVEFORM

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

Changing:
State Not
Known

N/A

Center Line
is High
Impedance

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X93154

APPLICATIONS INFORMATION

Electronic digitally controlled (XDCP) 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 retentivity of nonvolatile memory used for the storage of multiple potentiometer settings or data.

Low Voltage High Impedance Instrumentation Amplifier

Micro-Power LCD Contrast Control

Two terminal variable resistor.

U1A

10k

50k

U1C

Gain =

50k
10k

1 +

50k

TOTAL

)

(

U1 = LT1467

OUT

50k

U1B

10k

50k

X93154 (R

TOTAL

)

10k

3.3V

U1A

100k

300k

U1B

1 +

100k

50k + R

TOTAL

)

(

U1 = LMC6042

OUT

= -3.88

12V

100k

X93154 (R

TOTAL

)

240k

3.3V

100k

3.3V

50k

OUT

= -2.75V to -11.6V

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X93154

PACKAGING INFORMATION

0.118 ± 0.002

(3.00 ± 0.05)

0.040 ± 0.002

(1.02 ± 0.05)

0.150 (3.81)

Ref.

0.193 (4.90)

0.030 (0.76)

0.036 (0.91)
0.032 (0.81)

0.007 (0.18)
0.005 (0.13)

0.008 (0.20)

0.004 (0.10)

0.0216 (0.55)

7° Typ.

R 0.014 (0.36)

0.118 ± 0.002

(3.00 ± 0.05)

0.012 + 0.006 / -0.002

(0.30 + 0.15 / -0.05)

0.0256 (0.65) Typ.

8-Lead Miniature Small Outline Gull Wing Package Type M

NOTE:

1. ALL DIMENSIONS IN INCHES AND (MILLIMETERS)

0.220"

0.0256" Typical

0.025"
Typical

0.020"

Typical

8 Places

FOOTPRINT

Ref.

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X93154

8 BUMP FCP PACKAGE

Symbol

Min

Nominal

Max

Millimeters

Package Width

0.960

0.990

1.020

Package Length

0.940

0.970

1.000

Package Height

0.700

0.730

0.760

Body Thickness

0.620

0.630

0.640

Ball Height

0.085

0.100

0.115

Ball Diameter

0.100

0.115

0.130

Bump Name

X coordinate, µm

Y coordinate, µm

INCb

-153.70

377.00

Vcc

257.50

375.60

UDb

-382.00

123.20

CSb

382.00

114.50

382.00

-136.30

-382.00

-275.10

Vss

-115.30

-377.00

190.10

-377.00

Bottom View (Bumped Side)

Side View

1 2

AGH

YWW

Characteristics subject to change without notice.

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LIMITED WARRANTY

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.

TRADEMARK DISCLAIMER:

Xicor and the Xicor logo are registered trademarks of Xicor, Inc. AutoStore, Direct Write, Block Lock, SerialFlash, MPS, BiasLock and XDCP are also trademarks of
Xicor, Inc. All others belong to their respective owners.

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.

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X93154

Part Number X93154UX8I-3