PRELIMINARY TECHNICAL DATA

Nonvolatile Memory Digital Potentiometers

AD5231/AD5232/AD5233

REV PrF

12

22 MAR '01

Information contained in this Preliminary data sheet describes a product in the early definition stage. There is no guarantee that the

information contained here will become a final product in its present form. For latest information contact Walt Heinzer/Analog Devices, Santa

Clara, CA. TEL(408)382-3107; FAX (408)382-2708; walt.heinzer@analog.com

Latched Digital Outputs

A pair of digital outputs, O1 & O2, is available on the AD5231,

and the AD5233 parts that provide a nonvolatile logic 0 or logic

1 setting. O1 & O2 are standard CMOS logic outputs shown in

figure 2A. These outputs are ideal to replace functions often

provided by DIP switches. In addition, they can be used to drive

other standard CMOS logic controlled parts that need an

occasional setting change.

OUT P U T S

O1 & O2

PINS

V

DD

GND

Figure 2A. Logic Outputs O1 & O2.

Using Additional internal Nonvolatile EEMEM

The AD523x family of devices contains additional internal user

storage registers (EEMEM) for saving constants and other 8-bit

data. Table 6 provides an address map of the internal storage

registers shown in the functional block diagrams as EEMEM1,

EEMEM2, … EEMEMn, and bytes of USER EEMEM.

Table 6: EEMEM Address Map

EEMEM Contents of each device

EEMEM(ADDR)

EEMEM

Address

(ADDR)

AD5231 (16B)

AD5232

(8B)

AD5233

(8B)

0000

RDAC

RDAC1

RDAC1

0001

O1 & O2

RDAC2

RDAC2

0010

USER 1

USER 1

RDAC3

0011

USER 2

USER 2

RDAC4

0100

USER 3

USER 3

O1 & O2

0101

USER 4

USER 4

USER 1

***

***

***

***

1111

USER 14

USER 14

USER 11

NOTES:

1.

RDAC data stored in EEMEM locations are transferred to

their corresponding RDAC REGISTER at Power ON, or

when the following instructions are executed Inst#1 and

Inst#8.

2.

O1 & O2 data stored in EEMEM locations are transferred

to their corresponding DIGITAL REGISTER at Power ON,

or when the following instructions are executed Inst#1 and

Inst#8.

3.

USER data are internal nonvolatile EEMEM registers

available to store and retrieve constants using Inst#3 and

Inst#9 respectively.

4.

AD5231 EEMEM locations are 2 bytes each (16-bits) of

data, while the AD5232 & AD5233 are 1 byte each (8-bits).

Detail Programmable Potentiometer Operation

The actual structure of the RDAC is designed to emulate the

performance of a mechanical potentiometer. The RDAC

contains a string of connected resistor segments, with an array of

analog switches that act as the wiper connection to several

points along the resistor array. The number of points is the

resolution of the device. For example, the AD5232 has 256

connection points allowing it to provide better than 0.5% set-

ability resolution. Figure 3 provides an equivalent diagram of

the connections between the three terminals that make up one

while one of the switches SW(0) to SW(2

a time depending upon the resistance step decoded from the

A

X

R

S

R

S

R

S

W

X

B

X

RD A C

W IPER

R E G IST ER

&

DE CO D E R

R

S

= R

AB

/ N

SW

A

SW

B

SW (0 )

SW (1 )

DIG IT A L

CIR CUIT R Y

O M ITTE D FO R

CL A R IT Y

Figure 3. Equivalent RDAC structure

TEST CIRCUITS

Figures X7 to X15 define the test conditions used in the product

specification's table.

Figure X7. Potentiometer Divider Nonlinearity error test circuit

(INL, DNL)