analog devices fax-an-demand hotline - page 3~ --. analog w devices i low cost, 3 1/2 digit logic powered dpm with led displays ad2021 i features "second generation" mos-lsi design large 0.5#' (13mm) led dilplayl -t5vdc logic powered :t1.999v, :t199.9mv or :t19.99v full scale ranges limit8d differential input low power consumption: 2.0 watts small size, industry standard case design appltca tiohs general purpose logic powered dpm applieations portable applications requiring low power consumption general description the ad2021 is a low cost, 3~ digit, +5v dc logic powered digital panel meter with large led displays. while designed for general purpose dpm applications. the small size, light weight and low power consumption of the ad2021 make it an ideal digital readout for modern, compact instrument designs. the benefits of "second generation" design the ad2021 is designed around mos-lsi (metal-oxide-semi. conductor. large scale integration) integrated circuits, which greatly reduce the number of components, and thereby tbe size, and reduce power consumption to 2.0 watts. both the lower power consumption and fewer interconnections between components promise greatly increased reliability, and tbe cir- cuit design maintains the performance and features of earlier dpms. large 0.5 inch (13mm) led displays offer the visual appeal of gas discharge displays with the ruggedness and life- time of all solid state devices. excellent performance and easy application the ad2021 measures input voltage over a full scale range of :t1.999v de or :!:199.9mv dc ("s" option) with an accuracy of :!:o.os,," reading %0.025% full scale :i: 1 digit. using the "limited differential" input first used on analog devices' ad2010, the ad2021 prevents ground loop problems and provides 35 to sodb of common mode rejection at common mode voltages up to :l:200mv. normal mode rejection is 4odb at 50hz to 60hz. bcd data outputs are provided in a bit parallel. character serial format compatible to cmos logic systems. for those applica- tions requiring parallel bcd data. schemes for making the ser- ial to parallel conversion are available. controls to hold readings, select decimal points and blank the display are provided. designed and built for reliability the ad2021 is packaged in analog devices' logic powered dpm case size, only 1.25 incbes (32mm) deep. the small size of this dpm makes it easy to accommodate in any instrument rev. a information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of analog devices. figure 1. ad2021 bit parallel character serial to full parallel data conversion. ad2021 pin connections are shown in parentheses. for detailed infonnation, contact factory. one technology way, p.o. box 9106. norwood. ma 02062.9106, u.s.a. 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 (typical at +25c and nominal power supply voltage) design, and since several other manufacturers now use the same pand cutout for logic powered dpms, this industry standard- ization allows mechanical second sourcing. in addition, the ad2021 uses the same pin connections as the ad2010 (except in bcd outputs, of course:) as a convenience to allow updating designs to take advantage of the second generation design and larger display of the ad2021. each ad2021 receives a full one week failure free bum-in before shipment. display output . light emitting diode, planar seven segment display read- outs, 0.5" (l3mm) high for three data digits, 100% over- range and negative: polarity indication. overload indicated by flashing display, polarity remains valid. . decimal points selectable: at input connector. . display blanking on three data digits (does not affect overrange digit, polarity sign of decimal points). analog input . configuration: bipolar, limited differential . full scale range: :t1.999v or :t199.9mv ("s" option) :t 19. 99v ("v" option) . automatic polarity . auto zero . input impedance: 100mq (lmq - "v" option) . bias current: sofa . overvoltage protection: ;l:sov dc, sustained accuracy . ;1:0.05% reading ;1:0.025% full scale :tl digiti . resolution: imv,10mv ("v" option) or 100pv ("s" option) . temperature rangez: 0 to +soc operating; -25c to +85c storage . temperature coefficient: gain: soppm/oc zero: auto zero . warm-up time to rated accuracy: less than one minute . settling time to rated accuracy: 0.4 second normal mode rejection . 40db at 50-60hz 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 conversions per second . hold and read on command control inputs . display blankin2: (ttl, dtl compatible, 2 ttl loads). logic "0" or grounding blanks the three data digits only, not the decimal points, overrange digit (if on) and polar- ity sign. logic "i" or open circuit for normal operation. display blanking has no effect on output data and the display reading is valid immediately upon removal of a blanking signal. . hold: (cmos, dtl, ttl compatible, llp ttl load). logic "0" or grounding causes the dpm to cease conver- sions and display the data from the last conversion. logic "i" or open circuit for normal operation. after the "hold" input is removed, one to two conversions are needed before the reading is valid. . decimal points: grounding or logic "0" will illuminate the desired decimal point. external drive circuitry must sink 3sma peak at a 25% duty cycle when the decimal points are illuminated. da t a outputs (see application section for details on data outputs) . bcd data outputs: (cmos, lp ttl or lp schottky compatible), bit parallel, character serial format. . digit strobe outputs: (cmos, dtl, ttl compatible, one ttl load). logic "1" on any of these lines indicates the output data is valid for that digit. . polarity output: (cmos, ttl, dtl compatible, one ttl load). logic "i" indicates positive polarity input, logic "0" indicates negative polarity. . status: (cmos or lp ttl compatible). when this signal is at logic" 1", the output data is valid. . clock: (cmos, dtl, ttl compatible, one ttl load). the clock signal is brought out to facilitate conversion from character serial to parallel data. . interfacing data outputs. the: bcd data outputs are in a bit parallel, character serial format. there are four' bcd bit outputs (1,2,4,8) and four digit outputs (10,101, 102, 103). the bcd digits are gated onto the output lines sequentially, and the bcd bits are valid fot the digit whose digit line is high. the data is valid except when being updated which occurs within 2 milliseconds after the status line goes low. reference output . a 6.4v :t5% analog reference output is made available. this reference should be buffered and filtered if use in external circuitry is desired. power input . +5v dc ;1:5%, 1.45 watts calibration adjustments (see application section for calibration instructions) . gain . zero . recommended recalibration interval: six months size . 3"w x 1.8"h x 1.33"d (76 x 46 x 34mm) . 1.90" (48mm) overall depth to rear of card edge connector. . panel cutout required: 3.17'5" x uno" (80.65 x 45.97mm). weight . 4 ounces, (115 grams) options - ordering guide . input voltage range: ad2021 - 1.999v dc full s.cale ad2021/s - 199.9mv dc full scale ad2021/v - 19.99v dc full scale connector . 30 pin, 0.156" spacing card edge connector. viking 2vklsd/1-2 or equivalent. . optional: order aclsol notes j guaranteed at 25c and nominal supply voltage ~ guaranteed specifications subj~t to change without notice. -2- rev. a obsolete
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