PRELIMINARY TECHNICAL DATA
Nonvolatile Memory
a
Digital Potentiometers
AD5231/AD5232/AD5233
FEATURES
FUNCTIONAL BLOCK DIAGRAMS
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
AD5231
C S
VD D
AD DR
D ECO D E
R D AC 1
REGISTER
C LK
SDI
R D AC 1
SDI
A1
W 1
B1
SERIAL
EEMEM1
INTERFACE
SDO
G ND
SDO
W P
D IG ITAL 2
REGISTER
O1
O2
D IG ITAL
O UTPU T
BUFFER
2
EEMEM
C ON TR O L
R D Y
PR
APPLICATIONS
EEMEM2
VSS
28 BYTES
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
USER EEM EM
AD5232
C S
VDD
ADDR
DECODE
R DAC1
R DAC1
C LK
SDI
R EG ISTER
A1
W 1
B1
SDI
SER IAL
G ND
EEM EM 1
IN TERFAC E
SDO
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.
R DAC2
SDO
W P
R DAC2
R EG ISTER
A2
W 2
B2
EEM EM
C ON TR O L
R DY
PR
EEM EM 2
14 BY T ES
VSS
U S ER E EM E M
AD5233
C S
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.
VDD
ADDR
DECODE
R DAC1
R DAC1
C LK
SDI
R EG ISTER
A1
W 1
B1
SDI
SER IAL
EEM EM 1
IN TERFAC E
SDO
R DAC2
SDO
W P
R DAC2
R EG ISTER
A2
W 2
B2
EEM EM
C ON TR O L
R DY
G ND
EEM EM 2
11 BY T ES
U S ER E EM E M
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 (RWB) by one position segment of
the device's end-to-end resistance (RAB). 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.
R DAC3
R DAC3
R EG ISTER
O1
O2
A3
W 3
B3
D IGITAL
O UTPU T
BUFFER
EEM EM 3
2
R DAC4
D IGITAL 5
R EG ISTER
R DAC4
A4
R EG ISTER
W 4
PR
B4
EEM EM 5
EEM EM 4
VSS
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.
REV PrF, 22 MAR '01
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or other rights of third parties, which may result from its use. No license is granted by
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