XICOR X9116WS8I, X9116WS8-2.7, X9116WS8, X9116WM8I-2.7, X9116WM8I Datasheet

A V A I L A B L E

AN99 • AN115 • AN120 • AN124 • AN133 • AN134

A

PPLICATION

N

OTE

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

= 2.7V and 5V

CC

• Active current < 50µA max.

• Standby current < 1µA max.

•R

• Packages: MSOP-8, SOIC

TOTAL

= 10K Ω

™

)

DESCRIPTION

The Xicor X9116 is a digitally controlled nonvolatile
potentiometer designed to be used in trimmer applica­tions. 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 reli­ability of a solid state solution.

BLOCK DIAGRAM

V

CC

Up/Down

(U/D

)

Increment

(INC)

Device Select

(CS)

(Supply Voltage)

Control

and

Memory

V

(Ground)

SS

General

RH/V

RW/V

RL/V

R

H

W

L

RW-RL Resistance

R

H

*

3

2

1

0

L

15

14

13

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.

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X9116

.

.

PIN DESCRIPTIONS

V

/R

and V

H

H

The high (V

/R

L

L

/R

) and low (V

H

H

/R

) terminals of the

L

L

X9116 are equivalent to the fixed terminals of a
mechanical potentiometer. The minimum voltage is
V

and the maximum is V

SS

V

/R

W

W

R

/R

is the wiper terminal and is equivalent to the

w

w

CC

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 move­ment 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 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 X9116
will be placed in the low power standby mode until the
device is selected once again.

PIN CONFIGURATION

SOIC/MSOP

INC

U/D

VH/R

1

2

X9116

3

H

V

SS

4

V

8

CC

CS

7

VL/R

6

5

VW/R

L

W

PIN NAMES

Symbol Description

V

V

W

V

V

V

U/D

INC

H

L

CS

/R

/R

/R

SS

CC

H

W

L

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 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 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
V

change). The R

W

value for the device can tem-

TOTAL

(INC to

IW

porarily be reduced by a significant amount if the wiper
is moved several positions.

When the device is powered-down, the last wiper posi­tion stored will be maintained in the nonvolatile mem­ory. 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.

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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 mem­ory 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 lat­est 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 recalls the previ­ously 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 pref­erence, system parameter changes due to tempera­ture drift, etc.

MODE SELECTION

CS INC U/D Mode

L H Wiper Up

L L Wiper Down

H X Store Wiper Position

H X X Standby Current

L X No Store, Return to Standby

SYMBOL TABLE

WAVEFORM INPUTS OUTPUTS

Must be
steady

May change
from Low to
High

May change
from High to
Low

Don’t Care:
Changes
Allowed

N/A Center Line

Will be
steady

Will change
from Low to
High

Will change
from High to
Low

Changing:
State Not
Known

is High
Impedance

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.

REV 1.2 2/5/03

www.xicor.com

Characteristics subject to change without notice.

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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

and V

V = |V

with respect to V

CC

/R

–V

H

/R

H

L

| ............................................ 5.5V

L

/R

, V

/R

H

H

...................–1V to +7V

SS

L

L

Lead temperature (soldering 10 seconds)..........300°C

I

(10 seconds) ............................................ ±10.0mA

W

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 specifi­cation) is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect
device reliability.

RECOMMENDED OPERATING CONDITIONS

Temperature Min. Max.

Commercial 0°C +70°C

Industrial –40°C +85°C

Supply Voltage (V

) Limits

CC

X9116 5V ±10%

X9116-2.7 2.7V to 5.5V

POTENTIOMETER CHARACTERISTICS (Over recommended operating conditions unless otherwise stated)

Limits

Symbol Parameter

R

TOTAL

V

V

VH

VL

End to end resistance variation –20 +20 %

V

/R

terminal voltage V

H

H

VL/RL terminal voltage V

Power rating 10 mW R

R

W

R

W

I

W

Wiper resistance 200 400 Ω IW = 1mA, VCC = 5V
Wiper resistance 400 1000 Ω IW = 1mA, VCC = 2.7V

Wiper current -5.0 +5.0 mA

SS

SS

V

CC

V

CC

VV

VVSS = 0V

Test Conditions/NotesMin. Typ. Max. Unit

0V

SS

TOTAL

= 10 KΩ

Noise -120 dBV√Hz Ref: 1kHz

Resolution 6 %

Absolute linearity

Relative linearity

R

temperature coefficient ±300 ppm/°C

TOTAL

(2)

(1)

-1 +1 MI

-0.2 +0.2 MI

(3)

(3)

V

w(n)(actual)–Vw(n)(expected)

V

w(n+1)

–[V

w(n)+MI

]

Ratiometric temperature coefficient ±20 ppm/°C

C

H/CL/CW

Potentiometer capacitances 10/10/25 pF See Circuit #3

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

Ml Maximum.

(2) Relative linearity is a measure of the error in step size between taps = V
(3) 1 Ml = Minimum Increment = R

REV 1.2 2/5/03

TOT

/15.

www.xicor.com

W(n+1)

–[V

+ Ml] = ±0.2 Ml.

w(n)

Characteristics subject to change without notice.

(actual)–V

w(n)

(expected)) = ±1

w(n)

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