PRELIMINARY TECHNICAL DATA
a
Nonvolatile Memory
Digital Potentiometers

AD5231/AD5232/AD5233

REV PrF, 22 MAR '01
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responsibility is assumed by Analog Devices for its use; nor for any infringements of patents
or other rights of third parties, which may result from its use. No license is granted by
implication or otherwise under any patent or patent rights of Analog Devices.

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Fax:617/326-8703 © Analog Devices, Inc., 1999

FEATURES
Nonvolatile Memory Preset Maintains Wiper Settings
AD5231 Single, 1024 Position Resolution
AD5232 Dual, 256 Position Resolution
AD5233 Quad, 64 Position Resolution
10K, 50K, 100K Ohm Terminal Resistance
Linear or Log taper Settings
Increment/Decrement Commands, Push Button Command
SPI Compatible Serial Data Input with Readback Function
+3 to +5V Single Supply or ±2.5V Dual Supply Operation
User EEMEM nonvolatile memory for constant storage

APPLICATIONS
Mechanical Potentiometer Replacement
Instrumentation: Gain, Offset Adjustment
Programmable Voltage to Current Conversion
Programmable Filters, Delays, Time Constants
Line Impedance Matching
Power Supply Adjustment
DIP Switch Setting
GENERAL DESCRIPTION
The AD5231/AD5232/AD5233 family provides a single-
/dual-/quad-channel, digitally controlled variable resistor (VR)
with resolutions of 1024/256/64 positions respectively. These
devices perform the same electronic adjustment function as a
potentiometer or variable resistor. The AD523X’s versatile
programming via a Micro Controller allows multiple modes of
operation and adjustment.
In the direct program mode a predetermined setting of the
RDAC register can be loaded directly from the micro controller.
Another key mode of operation allows the RDAC register to be
refreshed with the setting previously stored in the EEMEM
register. When changes are made to the RDAC register to
establish a new wiper position, the value of the setting can be
saved into the EEMEM by executing an EEMEM save
operation. Once the settings are saved in the EEMEM register
these values will be transferred automatically to the RDAC
register to set the wiper position at system power ON. Such
operation is enabled by the internal preset strobe and the preset
can also be accessed externally.
The basic mode of adjustment is the increment and decrement
command controlling the present setting of the Wiper position
setting (RDAC) register. An internal scratch pad RDAC register
can be moved UP or DOWN, one step of the nominal terminal
resistance between terminals A-and-B. This linearly changes the
wiper to B terminal resistance (R
WB
) by one position segment of
the device's end-to-end resistance (R
AB
). For
exponential/logarithmic changes in wiper setting, a left/right
shift command adjusts levels in +/-6dB steps, which can be
useful for sound and light alarm applications.
The AD523X are available in the thin TSSOP package. All
parts are guaranteed to operate over the extended industrial
temperature range of -40°C to +85°C.

FUNCTIONAL BLOCK DIAGRAMS
RDAC1
RDAC1
REGISTER
SERIAL
INTERFACE
SDI
SDO
EEMEM1
CS
CLK
SDI
SDO
V
DD
A
1
W
1
V
SS
WP
AD5231
ADDR
DECODE
B
1
DIGITAL
OUTPUT
BUFFER
DIGITAL 2
REGISTER
EEMEM2
O
1
O
2
2
RDY
GND
EEMEM
CONTROL
PR
28 BYTES
USER EEMEM

RDAC1RDAC1
REGISTER
SERIAL
INTERFACE
SDI
SDO
EEMEM1
CS
CLK
SDI
SDO
V
DD
A
1
W
1
V
SS
WP
AD5232
ADDR
DECODE
B
1
RDAC2
RDAC2
REGISTER
EEMEM2
RDY
GND
EEMEM
CONTROL
A
2
W
2
B
2
PR
14 BYTES
USER EEMEM

RDAC1RDAC1
REGISTER
SERIAL
INTERFACE
SDI
SDO
EEMEM1
CS
CLK
SDI
SDO
V
DD
A
1
W
1
WP
AD5233
ADDR
DECODE
B
1
RDAC2
RDAC2
REGISTER
EEMEM2
RDY
GND
EEMEM
CONTROL
A
2
W
2
B
2
RDAC3RDAC3
REGISTER
EEMEM3
A
3
W
3
V
SS
B
3
RDAC4
RDAC4
REGISTER
EEMEM4
A
4
W
4
B
4
DIGITAL
OUTPUT
BUFFER
DIGITAL 5
REGISTER
EEMEM5
2
O
1
O
2
PR
11 BYTES
USER EEMEM