AD2021

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ANALOG DEVICES fAX-aN-DEMAND HOTLINE - Page 3~ --.ANALOG W DEVICES I Low Cost,3 1/2Digit LogicPoweredDPM withLEDDisplays AD2021 I

FEATURES

"Second Generation"MOS-LSI Design Large0.5#'(13mm) LED Dilplayl -t5VDC LogicPowered :t1.999V,:t199.9mVor :t19.99VFullScaleRanges Limit8dDifferentialInput Low Power Consumption: 2.0Watts SmallSize,IndustryStandardCaseDesign APPLtCA TIOHS General Purpose Logic Powered DPM Applieations PortableApplicationsRequiring Low Power Consumption GENERAL DESCRIPTION The AD2021 isa low cost,3~ digit,+5V dc logicpowered digitalpanel meter with largeLED displays.While designedfor generalpurpose DPM applications.the smallsize,lightweight and low power consumption of the AD2021 make itan ideal digitalreadout formodern, compact instrumentdesigns. THE BENEFITS OF "SECOND GENERATION" DESIGN The AD2021 isdesigned around MOS-LSI (Metal-oxide-Semi. conductor. Large Scale Integration)integratedcircuits,which greatlyreduce the number of components, and thereby tbe size,and reduce power consumption to 2.0 watts. Both the lower power consumption and fewer interconnectionsbetween components promise greatlyincreasedreliability,and tbe cir- cuitdesignmaintains the performance and featuresof earlier DPMs. Large 0.5 inch (13mm) LED displaysofferthe visual appeal of gas dischargedisplayswith the ruggednessand life- time of allsolidstatedevices. EXCELLENT PERFORMANCE AND EASY APPLICATION The AD2021 measures inputvoltageover a fullscalerange of :t1.999V de or :!:199.9mVdc ("S" option) with an accuracy of :!:O.OS,,"reading%0.025% fullscale:I:1 digit.Using the "limiteddifferential"input firstused on Analog Devices' AD2010, the AD2021 preventsground loop problems and provides35 to SOdB of common mode rejectionat common mode voltagesup to :l:200mV.Normal mode rejectionis 4OdB at 50Hz to 60Hz. BCD data outputs are provided ina bitparallel.characterserial format compatible to CMOS logicsystems.For those applica- tionsrequiringparallelBCD data.schemes for making the ser- ialto parallelconversionare available.Controls to hold readings, selectdecimal pointsand blank the displayare provided. DESIGNED AND BUILT FOR RELIABILITY The AD2021 ispackaged in Analog Devices'logicpowered DPM case size,only 1.25 incbes(32mm) deep. The smallsize of thisDPM makes iteasy to accommodate inany instrument REV. A Informationfurnishedby Analog Devices isbelievedto be accurateand reliable.However, no responsibilityisassumed by Analog Devicesforits use,nor forany infringementsof patentsor other rightsofthirdparties which may resultfrom itsuse. No licenseisgranted by implicationor otherwise under any patentor patentrightsof Analog Devices. Figure1.AD2021 BitParallelCharacterSerialto FullParallel Data Conversion.AD2021 Pin ConnectionsAre Shown in Parentheses. For detailedinfonnation,contactfactory. Tel: 617/329-4700 Fax: 617/326-8703 Twx: 710/394.6577 Telex: 924491 Cable: ANALOG NORWOODMASS OBSOLETE

ANALOG DEVICES fAX-ON-DEMAND HOTLINE - Page 35 AD2021-SPECIFICATIONS(typicalat+25°Candnominalpowersupplyvoltage) design,and sinceseveralother manufacturers now use the same pand cutout forlogicpowered DPMs, thisindustrystandard- izationallowsmechanical second sourcing.In addition,the AD2021 usesthe same pin connections asthe AD2010 (except in BCD outputs,of course:)as a convenience to allowupdating designsto take advantage of the second generationdesignand largerdisplayof the AD2021. Each AD2021 receivesa full one week failurefreebum-in before shipment. DISPLAY OUTPUT . Lightemittingdiode,planarseven segment displayread- outs,0.5" (l3mm) high for threedata digits,100% over- range and negative:polarityindication.Overload indicated by flashingdisplay,polarityremains valid. . Decimal pointsselectable:at input connector. . Displayblankingon threedata digits(doesnot affect overrangedigit,polaritysignof decimal points). ANALOG INPUT . Configuration:bipolar,limiteddifferential . Full ScaleRange: :t1.999V or :t199.9mV ("S" option) :t19.99V ("V" option) . AutomaticPolarity. AutoZero . InputImpedance:100MQ (lMQ - "V" option) . BiasCurrent:SOFA . OvervoltageProtection:;l:SOVdc,sustained ACCURACY . ;1:0.05%reading;1:0.025%fullscale:tldigitI . Resolution:ImV,10mV ("V" option) or 100pV ("S" option) . Temperature Rangez: 0 to +SO°C operating;-25°C to +85°C storage . Temperature Coefficient:Gain: SOppm/oCZero: auto zero . Warm-Up Time to Rated Accuracy: lessthan one minute . SettlingTime to Rated Accuracy: 0.4 second NORMAL MODE REJECTION .40dB at50-60Hz COMMON MODE REJECTION .AD2021: 35dB (dc -10kHz) .AD2021/S: SOdS (dc -10kHz) .AD2021/V: lSdB (de -10kHz) COMMON MODE VOLT AGE . :!:20OmV CONVERSION RATE .5 conversionsper second . Hold and read on command CONTROL INPUTS . Display Blankin2:(TTL, DTL compatible,2 TTL loads). Logic "0" or grounding blanks the threedata digitsonly, not the decimal points,overrangedigit(ifon) and polar- itysign.Logic "I" or open circuitfornormal operation. Displayblankinghas no effecton output data and the displayreadingisvalidimmediately upon removal of a blankingsignal. . Hold: (CMOS, DTL, TTL compatible,lLP TTL load). Logic "0" or grounding causesthe DPM to ceaseconver- sionsand displaythe data from the lastconversion.Logic "I" or open circuitfornormal operation.After the "Hold" input isremoved, one to two conversionsare needed before the readingisvalid. . Decimal Points:Grounding or Logic "0" willilluminate the desireddecimal point.Externaldrivecircuitrymust sink 3SmA peak at a 25% duty cycle when the decimal points are illuminated. DA T A OUTPUTS (See ApplicationSection fordetailson data outputs) . BCD Data Outputs: (CMOS, LP TTL or LP Schottky compatible),bitparallel,characterserialformat. . DigitStrobe Outputs: (CMOS, DTL, TTL compatible, one TTL load).Logic "1" on any of theselinesindicates the output data isvalidfor thatdigit. . PolarityOutput: (CMOS, TTL, DTL compatible,one TTL load).Logic "I" indicatespositivepolarityinput, logic"0" indicatesnegativepolarity. . Status:(CMOS or LP TTL compatible).When thissignal isat Logic" 1",the output data isvalid. . Clock: (CMOS, DTL, TTL compatible,one TTL load). The clock signalisbrought out to facilitateconversion from characterserialto paralleldata. . INTERFACING DATA OUTPUTS. The:BCD data outputS arein a bitparallel,characterserialformat.There arefour' BCD bitoutputs (1,2,4,8) and four digitoutputs (10°,101, 102, 103).The BCD digitsaregated onto the output lines sequentially,and the BCD bitsarevalidfOTthe digitwhose digitlineishigh.The data isvalidexcept when being updated which occurswithin 2 millisecondsafterthe statUsline goes low. REFERENCEOUTPUT .A 6.4V :t5% analog referenceoutput ismade available. This referenceshould be bufferedand filteredifuse in externalcircuitryisdesired. POWER INPUT . +5V dc ;1:5%,1.45 watts CALIBRATION ADJUSTMENTS (See ApplicationSectionfor calibrationinstructions) . Gain. Zero . Recommended recalibrationinterval:sixmonths SIZE . 3"W x 1.8"H x 1.33"D (76 x 46 x 34mm) . 1.90"(48mm) overalldepthto rearofcardedgeconnector. WEIGHT . 4 ounces,(115grams) OPTIONS - ORDERING GUIDE . InputVoltageRange:AD2021 - 1.999V dc FullS.cale AD2021/S - 199.9mV dc FullScale AD2021/V - 19.99Vdc FullScale CONNECTOR . 30 pin,0.156" spacingcard edge connector.Viking 2VKlSD/1-2 or equivalent. . Optional:OrderAClSOl NOTES JGuaranteed at25°C and nominal supply voltage ~Guaranteed Specificationssubj~t to change without notice. -2- REV. A OBSOLETE