Datasheet AD5235-EP (Analog Devices)

Nonvolatile Memory, Dual 1024-Position Digital Potentiometer Enhanced Product AD5235-EP FEATURES FUNCTIONAL BLOCK DIAGRAM Dual-channel, 1024-position resolution AD5235-EP 25 kΩ nominal resistance ADDR VDD CS DECODE RDAC1 Low temperature coefficient: 35 ppm/°C REGISTER CLK A1 Nonvolatile memory stores wiper settings SERIAL W1 SDI Permanent memory write protection INTERFACE B1 RDAC1 SDO EEMEM1 Wiper setting readback Resistance tolerance stored in EEMEM POWER-ON PR RESET RDAC2 Predefined linear increment/decrement instructions REGISTER A2 WP Predefined ±6 dB/step log taper increment/decrement EEMEM W2 RDY CONTROL instructions B2 EEMEM2 RDAC2 SPI-compatible serial interface V +2.7 V to +5 V single supply or ±2.5 V dual supply SS 26 BYTES RTOL* 26 bytes extra nonvolatile memory for user-defined USER EEMEM GND information
1 00
100-year typical data retention, T
5-
A = 55°C *RAB TOLERANCE
18 09
Power-on refreshed with EEMEM settings
Figure 1.
Enhanced Features
In scratchpad programming mode, a specific setting can be
Supports defense and aerospace applications (AQEC)
programmed directly to the RDAC2 register that sets the resistance
Temperature range: −40°C to +125°C
between Terminal W and Terminal A, and Terminal W and
Controlled manufacturing baseline 1 assembly/test site
Terminal B. This setting can be stored into the EEMEM and
1 fabrication site
is restored automatically to the RDAC register during system
Product change notification
power-on.
Qualification data available on request
The EEMEM content can be restored dynamically or through
APPLICATIONS
external PR strobing, and a WP function protects EEMEM contents.
DWDM laser diode driver, optical supervisory systems
To simplify the programming, the independent or simultaneous
Mechanical potentiometer replacement
linear-step increment or decrement commands can be used to move
Instrumentation: gain, offset adjustment
the RDAC wiper up or down, one step at a time. For logarithmic
Programmable voltage-to-current conversion
±6 dB changes in the wiper setting, the left or right bit shift
Programmable filters, delays, time constants
command can be used to double or halve the RDAC wiper setting.
Programmable power supply
The AD5235-EP patterned resistance tolerance is stored in the
Low resolution DAC replacement
EEMEM. Therefore, in readback mode, the host processor can
Sensor calibration
know the actual end-to-end resistance. The host can execute the
GENERAL DESCRIPTION
appropriate resistance step through a software routine that simplifies The AD5235-EP is a dual-channel, nonvolatile memory,1 open-loop applications as well as precision calibration and digitally controlled potentiometer2 with 1024-step resolution. tolerance matching applications. The device performs the same electronic adjustment function as a The AD5235-EP is available in a thin, 16-lead TSSOP package. mechanical potentiometer with enhanced resolution, solid state The part is guaranteed to operate over the extended industrial reliability, and superior low temperature coefficient performance. temperature range of −40°C to +125°C. The AD5235-EP’s versatile programming via an SPI®-compatible serial interface allows 16 modes of operation and adjustment Full details about this enhanced product, including theory of including scratchpad programming, memory storing and restoring, operation, register details, and applications information, are increment/decrement, ±6 dB/step log taper adjustment, wiper setting available in the AD5235 data sheet, which should be consulted readback, and extra EEMEM1 for user-defined information such as in conjunction with this data sheet. memory data for other components, look-up tables, or system 1 The terms nonvolatile memory and EEMEM are used interchangeably. 2 The terms digital potentiometer and RDAC are used interchangeably. identification information.
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Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ELECTRICAL CHARACTERISTICS INTERFACE TIMING AND EEMEM RELIABILITY CHARACTERISTICS Timing Diagrams ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS TEST CIRCUITS OUTLINE DIMENSIONS ORDERING GUIDE