Description

The ADN2850 is a dual-channel, nonvolatile memory, digitallycontrolled resistors?with 1024-step resolution, offeringguaranteed maximum low resistor tolerance error of ?8%. Thedevice performs the same electronic adjustment function as amechanical rheostat with enhanced resolution, solid statereliability, and superior low temperature coefficientperformance. The versatile programming of the ADN2850 viaan SPI?-compatible serial interface allows 16 modes ofoperation and adjustment including scratchpad programming,memory storing and restoring, increment/decrement, ?6 dB/steplog taper adjustment, wiper setting readback, and extra EEMEM?for user-defined information such as memory data for other components, look-up table, or system identificationinformation.In the scratchpad programming mode, a specific setting canbe programmed directly to the RDAC?register, which sets theresistance between Terminal W and Terminal B. This setting canbe stored into the EEMEM and is restored automatically to theRDAC register during system power-on.The EEMEM content can be restored dynamically or throughexternal PR strobing, and a WP function protects EEMEM contents. To simplify the programming, the independent orsimultaneous linear-step increment or decrement commandscan be used to move the RDAC wiper up or down, one step at atime. For logarithmic ?6 dB changes in the wiper setting, theleft or right bit shift command can be used to double or halve theRDAC wiper setting.The ADN2850 patterned resistance tolerance is stored in theEEMEM. The actual full scale resistance can, therefore, beknown by the host processor in readback mode. The host canexecute the appropriate resistance step through a softwareroutine that simplifies open-loop applications as well asprecision calibration and tolerance matching applications.The ADN2850 is available in the 5 mm ? 5 mm 16-lead framechip scale LFCSP and thin, 16-lead TSSOP package. The part isguaranteed to operate over the extended industrial temperaturerange of ?40?C to +85?C.Applications SONET, SDH, ATM, Gigabit Ethernet, DWDM laser diode driver, optical supervisory systems Mechanical rheostat replacement Instrumentation gain adjustment Programmable filters, delays, time constants Sensor calibration

Type:

Part number: EVAL-ADN2850SDZ

More details from Analog Devices Inc.