AD5231 Datasheet, PDF (1/24 Pages) Analog Devices – Nonvolatile Memory, 1024-Position Digital Potentiometers

a
Nonvolatile Memory,
1024-Position Digital Potentiometers
AD5231^*
FEATURES
Nonvolatile Memory¹ Preset Maintains Wiper Settings
1024-Position Resolution
Full Monotonic Operation
10 k⍀, 50 k⍀, and 100 k⍀ Terminal Resistance
Permanent Memory Write-Protection
Wiper Settings Read Back
Linear Increment/Decrement
Log Taper Increment/Decrement
Push Button Increment/Decrement Compatible
SPI Compatible Serial Interface with Readback Function
3 V to 5 V Single Supply or ؎2.5 V Dual Supply
28 Bytes User Nonvolatile Memory for Constant Storage
100 Year Typical Data Retention T_A = 55؇C
APPLICATIONS
Mechanical Potentiometer Replacement
Instrumentation: Gain, Offset Adjustment
Programmable Voltage to Current Conversion
Programmable Filters, Delays, Time Constants
Line Impedance Matching
Power Supply Adjustment
Low Resolution DAC Replacement
FUNCTIONAL BLOCK DIAGRAM
CS
CLK
SDI
GND
ADDR
DECODE
SDI
SERIAL
INTERFACE
AD5231
V_DD
RDAC
RDAC
REGISTER
A
W
EEMEM1
B
SDO
WP
RDY
SDO
EEMEM
CONTROL
DIGITAL
REGISTER
2 _DIGITAL
O1
OUTPUT
O2
BUFFER
EEMEM2
28 BYTES
V_SS
USER EEMEM
PR
100
R_WA
75
R_WB
GENERAL DESCRIPTION
The AD5231 provides nonvolatile memory digitally controlled
potentiometers² with 1024-position resolution. These devices
perform the same electronic adjustment function as a mechanical
potentiometer. The AD5231’s versatile programming via a stan-
dard 3-wire serial interface allows 16 modes of operation and
adjustment, including scratch pad programming, memory stor-
ing and retrieving, increment/decrement, log taper adjustment,
wiper setting read back, and extra user-defined EEMEM.
In the scratch pad programming mode, a specific setting can be
programmed directly to the RDAC² register, which sets the resis-
tance at terminals W-A and W-B. The RDAC register can also
be loaded with a value previously stored in the EEMEM¹ regis-
ter. The value in the EEMEM can be changed or protected.
When changes are made to the RDAC register, the value of the
new setting can be saved into the EEMEM. Thereafter, such value
will be transferred automatically to the RDAC register during
system power ON. It is enabled by the internal preset strobe.
EEMEM can also be retrieved through direct programming and
external preset pin control.
50
25
0
0
256
512
768
1023
CODE – Decimal
Figure 1. R_WA(D) and R_WB(D) vs. Decimal Code
Other operations include linear step increment and decrement
commands such that the setting in the RDAC register can be
moved UP or DOWN, one step at a time. For logarithmic changes
in wiper setting, a left/right bit shift command adjusts the level
in ± 6 dB steps.
The AD5231 is available in thin TSSOP-16 package. All parts
are guaranteed to operate over the extended industrial tempera-
ture range of –40°C to +85°C.
NOTES
1_{The terms Nonvolatile Memory and EEMEM are used interchangeably.}
2_{The terms Digital Potentiometer and RDAC are used interchangeably.}
*Patent pending
REV. 0
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