AD5235 Series

The AD5235 is a dual-channel, nonvolatile memory, digitally controlled potentiometer with 1024-step resolution, offering guaranteed maximum low resistor tolerance error of ±8%. 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 versatile programming of the AD5235 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 EEMEM for user-defined information such as memory data for other components, look-up table, or system identification information.In the scratchpad programming mode, a specific setting can be programmed directly to the RDAC register, which 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 externalPRstrobing, and aWPfunction 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 patterned resistance tolerance is stored in the EEMEM. The actual end-to-end resistance can, therefore, be known by the host processor in readback mode. 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 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 +85°C.APPLICATIONSDWDM laser diode driver, optical supervisory systemsMechanical potentiometer replacementInstrumentation: gain, offset adjustmentProgrammable voltage-to-current conversionProgrammable filters, delays, time constantsProgrammable power supplyLow resolution DAC replacementSensor calibration