AD5235

Features:

Dual, 1024 Position Resolution
25K, 250K Ohm Terminal Resistance with 50ppm/°C Tempco
Nonvolatile Memory Preset
SPI Compatible Serial Data Input with Readback Function
Increment/Decrement Commands, Push Button Command
+3 to +5V Single Supply Operation
±2.5V Dual Supply Operation
30 bytes of general purpose nonvolatile memory


Application

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


Pinout




Specifications

Absolute Maximum Rating (TA = +25°C, unless otherwise noted)
VDD to GND..............................................................   -0.3, +7V
VSS to GND.................................................................    0V, -7V
VDD to VSS .........................................................................+7V
VA, VB, VW to GND .................................................    VSS, VDD
AX BX, AX WX, BX WX ......................................     ±20mA
Ox to GND...................................................................  0V, VDD
Digital Inputs & Output Voltage to GND ..................     0V, +7V
Operating Temperature Range........................ -40°C to +85°C
Maximum Junction Temperature (T_J MAX)...................   +150°C
Storage Temperature ....................................-65°C to +150°C
Lead Temperature (Soldering, 10 sec)..........................+300°C
Thermal Resistance JA,TSSOP-16..............................180°C/W 
Package Power Dissipation = (TJMAX - TA) / JA 
 


Description

The AD5235 provides a dual channel, digitally controlled variable  resistor (VR) with resolutions of 1024 positions. These devices  perform the same electronic adjustment function as a potentiometer or  variable resistor. The AD5235'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 AD5235 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.

An internal scratch pad RDAC register can be programmed by the  micro controller to set the resistance between terminals W-and-B.  Once the target value is achieved, the RDAC content register can be  placed in the non-volatile memory for automatic recall during Power  Up.  The AD5235 is available in the thin TSSOP-16 package.  All parts are  guaranteed to operate over the extended industrial temperature range  of -40°C to +85°C.