intersil X9C303 User Manual

®

www.BDTIC.com/Intersil

X9C303

Logarithmic Digitally Controlled Potentiometer (XDCP™)

Data Sheet January 24, 2007

Terminal Voltage ±5V, 100 T aps, Log Taper
Description

The Intersil 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 three-wire 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
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 potentio-meter
or as a two-terminal variable resistor in a wide variety of
applications ranging from control, to signal processing, to
parameter adjustment. Digitally
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.

, U/D, and INC inputs. The

-

controlled potentiometers

Features

• 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, 32kΩ ±15%

- Terminal voltages, ±5V

• Low power CMOS
= 5V

-V

CC

- Active current, 3mA max.

- Standby current, 750µA max.

• High reliability

- Endurance, 100,000 data changes per bit

- Register data retention, 100 years

• Packages

- 8 Ld TSSOP

- 8 Ld SOIC

- 8 Ld PDIP

FN8223.1

Block Diagram

U/D
INC

CS

V

CC

V

SS

7-Bit

Up/Down

Counter

7-Bit

Nonvolatile

Memory

Store and

Recall

Control

Circuitry

One

of

One­Hundred
Decoder

99

98

97

96

RH/V

H

Transfer

Gates

2

1

0

Resistor

Array

RL/V

RW/V

L

W

1

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1-888-INTERSIL or 1-888-468-3774

XDCP is a trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2005, 2007. All Rights Reserved

| Intersil (and design) is a registered trademark of Intersil Americas Inc.

All other trademarks mentioned are the property of their respective owners.

X9C303

www.BDTIC.com/Intersil

Ordering Information

PART NUMBER PART MARKING TEMPERATURE RANGE (°C) PACKAGE PKG. DWG. #

X9C303P X9C303P 0 to +70 8 Ld PDIP MDP0031
X9C303PI X9C303P I -40 to +85 8 Ld PDIP MDP0031
X9C303PIZ (Note) X9C303P ZI -40 to +85 8 Ld PDIP (300 mil) (Pb-free) MDP0031
X9C303PZ (Note) X9C303P Z 0 to +70 8 Ld PDIP (300 mil) (Pb-free) MDP0031
X9C303S8* X9C303S 0 to +70 8 Ld SOIC (150 mil) MDP0027
X9C303S8I* X9C303S I -40 to +85 8 Ld SOIC (150 mil) MDP0027
X9C303S8IZ* (Note) X9C303S ZI -40 to +85 8 Ld SOIC (150 mil) (Pb-free) MDP0027
X9C303S8Z* (Note) X9C303S Z 0 to +70 8 Ld SOIC (150 mil) (Pb-free) MDP0027
X9C303V8* 9C303 0 to +70 8 Ld TSSOP (4.4mm) M8.173
X9C303V8I* C303 I -40 to +85 8 Ld TSSOP (4.4mm) M8.173
X9C303V8IZ* (Note) C303 IZ -40 to +85 8 Ld TSSOP (4.4mm) (Pb-free) M8.173
X9C303V8Z* (Note) 9CC303 Z 0 to +70 8 Ld TSSOP (4.4mm) (Pb-free) M8.173
X9C303S8I-2.7 X9C303S G -40 to +85 8 Ld SOIC (150 mil) MDP0027
X9C303S8IZ-2.7 (Note) X9C303S ZG -40 to +85 8 Ld SOIC (150 mil) (Pb-free) MDP0027

NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate
termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL
classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.

*Add "T1" suffix for tape and reel.

Pin Descriptions

VH and V

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
V

and VH references the relative position of the terminal in

L

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 movement
and whether the counter is incriminated 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

Chip Select (CS)

The device is selected when the CS input is LOW. The
current counter value is stored in nonvolatile memory when
CS
the store operation is complete the device will be placed in
the low power standby mode until the device is selected
once again.

L

input.

is returned HIGH while the INC input is also HIGH. After

Pinout

X9C303

(8 LD SOIC, 8 LD TSSOP, 8 LD PDIP)

INC

(CS)

(V

)

U/D

CC

)

(INC

V

H

(U/D

)

V

SS

TOP VIEW

1

2

X9C303

3

4

Pin Names

SYMBOL DESCRIPTION

V

H

V

W

V

L

V

SS

V

CC

U/D
INC

CS
NC No Connection

High Terminal (Potentiometer)
Wiper Terminal (Potentiometer)
Low Terminal (Potentiometer)
Ground
Supply Voltage
Up/Down Control Input
Increment Control Input
Chip Select Control Input

8

7

6

5

CS

V

V

CC

L

W

L

(V

)

W

)

(V

SS

(V

)

H

(V

)

V

2

FN8223.1

January 24, 2007

X9C303

www.BDTIC.com/Intersil

Potentiometer Relationships

S100

V

H

(VS)

R99

R98

R2

R1

V

L

Gi20Log

R1R2. . . R

(Refer Test Circuit 1)

R1R2. . . R

-------------------------------------------------

+++ R

S99

S98

S3

S2

S1

+++

R

TOTAL

=

99

TOTAL

V

W

V

i

W

--------- VL0V=()==
V

S

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 t
R

value for the device can temporarily be reduced by a

TOTAL

significant amount if the wiper is moved several positions.

(INC to VW change). The

IW

Instructions and Programming

The INC, U/D and CS inputs control the movement of the
wiper along the resistor array. With CS
selected and enabled to respond to the U/D
HIGH to LOW transitions on INC
(depending on the state of the U/D

set LOW the device is

and INC inputs.

will increment or decrement

input) a seven-bit counter.
The output of this counter is decoded to select one of one­hundred 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 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
CS

HIGH. The new wiper position would be maintained until

LOW while taking

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 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
L H Wiper Up (not recommended)
L L Wiper Down (not recommended)

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.

3

FN8223.1

January 24, 2007