AD5235-EP Datasheet, PDF (1/16 Pages) Analog Devices – Nonvolatile Memory, Dual 1024-Position Digital Potentiometer

Nonvolatile Memory, Dual
1024-Position Digital Potentiometer
AD5235-EP
FEATURES
Dual-channel, 1024-position resolution
25 kΩ nominal resistance
Low temperature coefficient: 35 ppm/°C
Nonvolatile memory stores wiper settings
Permanent memory write protection
Wiper setting readback
Resistance tolerance stored in EEMEM
Predefined linear increment/decrement instructions
Predefined ±6 dB/step log taper increment/decrement
instructions
SPI-compatible serial interface
3 V to 5 V single supply or ±2.5 V dual supply
26 bytes extra nonvolatile memory for user-defined
information
100-year typical data retention, TA = 55°C
Power-on refreshed with EEMEM settings
Enhanced Features
Supports defense and aerospace applications (AQEC)
Temperature range: −40°C to +125°C
Controlled manufacturing baseline
1 assembly/test site
1 fabrication site
Enhanced product change notification
Qualification data available on request
APPLICATIONS
DWDM laser diode driver, optical supervisory systems
Mechanical potentiometer replacement
Instrumentation: gain, offset adjustment
Programmable voltage-to-current conversion
Programmable filters, delays, time constants
Programmable power supply
Low resolution DAC replacement
Sensor calibration
GENERAL DESCRIPTION
The AD5235-EP is a dual-channel, nonvolatile memory,¹
digitally controlled potentiometer² with 1024-step resolution.
The device performs the same electronic adjustment function as a
mechanical potentiometer with enhanced resolution, solid state
reliability, and superior low temperature coefficient performance.
The AD5235-EP’s versatile programming via an SPI®-compatible
serial interface allows 16 modes of operation and adjustment
including scratchpad programming, memory storing and restoring,
increment/decrement, ±6 dB/step log taper adjustment, wiper setting
readback, and extra EEMEM¹ for user-defined information such as
memory data for other components, look-up tables, or system
identification information.
Rev. 0
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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 that may result from its use. Specifications subject to change without notice. No
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FUNCTIONAL BLOCK DIAGRAM
CS
CLK
SDI
SDO
ADDR
DECODE
SERIAL
INTERFACE
RDAC1
REGISTER
AD5235-EP
EEMEM1
RDAC1
PR
POWER-ON
RESET
WP
RDY
EEMEM
CONTROL
RDAC2
REGISTER
EEMEM2
RDAC2
RTOL*
26 BYTES
USER EEMEM
V_DD
A1
W1
B1
A2
W2
B2
V_SS
GND
*RAB TOLERANCE
Figure 1.
In scratchpad programming mode, a specific setting can be
programmed directly to the RDAC² register that sets the resistance
between Terminal W and Terminal A, and Terminal W and
Terminal B. This setting can be stored into the EEMEM and
is restored automatically to the RDAC register during system
power-on.
The EEMEM content can be restored dynamically or through
external PR strobing, and a WP function protects EEMEM contents.
To simplify the programming, the independent or simultaneous
linear-step increment or decrement commands can be used to move
the RDAC wiper up or down, one step at a time. For logarithmic
±6 dB changes in the wiper setting, the left or right bit shift
command can be used to double or halve the RDAC wiper setting.
The AD5235-EP patterned resistance tolerance is stored in the
EEMEM. Therefore, in readback mode, the host processor can
know the actual end-to-end resistance. The host can execute the
appropriate resistance step through a software routine that simplifies
open-loop applications as well as precision calibration and
tolerance matching applications.
The AD5235-EP is available in a thin, 16-lead TSSOP package.
The part is guaranteed to operate over the extended industrial
temperature range of −40°C to +125°C.
Full details about this enhanced product, including theory of
operation, register details, and applications information, are
available in the AD5235 data sheet, which should be consulted
in conjunction with this data sheet.
1 _{The terms nonvolatile memory and EEMEM are used interchangeably.}
2 _{The terms digital potentiometer and RDAC are used interchangeably.}
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