analog devices fax-on-demand hotline - page 32 r-. analog w devices features led display with latched digital outputs small size, ughtweight automatic zero correction; max error: 0.05% :t: 1 digit high normal mode rejection: 4odb @ 50 or 60hz optional ratlometric operation leading "0" display blanking 5vdc powered applications medicaj/scientificlanalytic instruments data acquisition systems industrial weighing systems radouts in engineering units digi18l thennometen general description analog devices' model ad2010 represents an advance in price! performance capabilities of 3~ digit digital panel meters. the ad20l0 offers o.os% ~l digit maximum error with bipolar, single ended input, resolution of lostv, .and a common mode rejection ratio of 60db (cmrr) at %loom v (cmv). the ad20l0 features a light-cmitting-diode (led) display with a full scale range of 0 to ~l99.9 mirivolts, latched digital data outputs and control interface signals, and leading zero dis- play blanking. automatic-zero correction circuitry measures and compensates for offset and offset drift errors, thereby providing virtually no error. another useful feature of the ad20l0 is its sv de operation. the ad20l0 can operate from the users' sv de system supply, thereby eliminating the shield- ing and dc:coupling needed for line powered units when the ac line must be routed near signal leads. to satisfy most application requirements, the conversion rate of the ad2010 is normal1y 4 readings per second. however, an external trigger may be applied to vary the sampling rates from a maximum of 24 readings per second down to an indef'mite hold time. the ad2010 can also be connected for automaric conversion at its maximum conversion rate. during conversion, the previous reading is held by the latched logic. the numeric readout is available as bcd da.ta. applica.tion of the metering system in a computer or data logging system is made easy with the availability of the "overrange," "polarity, it. .. overload," and "status" signals. a simplified block diagram of the ad20l0, illustrating the features described above is shown in figure 1. foe detaikod information, contact &ctmy. rev. a infonnation 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. low cost, 3 1/2 digit dpm for oem applications ad2010 i '{. . ..'9 .~~ "", ,,-' ~, .' :!: -'," ,: ". "' "'- . ;. analog in analog ghd digital gnd 6vdo lied data { pou.rity signal overl,qai> signal overranae signal status signal. figure 1. simplified functional block diagram improved noise immunity, accuracy and zero stability dual-slope integration, as used in the ad2010 and as described in the tbeory of operation section, offers several design benefits. . conversion accuracy, for example, is independent of both the timing capacitor value and the clock frequency, since they affect both the up ramp and down ramp integration in the same ratio. . normal mode noise at line frequencies or its harmonics is rejected since the average value of this noise is zero over the integration period. . to achieve zero stability, a time interval during each conver- sion is provided to allow the automatic-zero correction cir- cuitry to measure and compensate for offset and offset drift errors, thereby, providing virtually no zero error. one t~hnology 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 analog section digital sea:tlcn 31ii digit a to 0 /888 obsolete
ahalog devices fax-oh-demahd hotlihe - page 33 ad201 0 -specifications (typical at +25c and +5v de unless otherwise noted) displa y ouj'put . display consists of four led's ( 0.27" (6.9mm) high). fol" data digits plus 100'11. overrange and polarity indication. . overload - three data digits display zeros and flashes. . decimal points - selectable at input connector. . leading "0" display blanking - controlled externally. input . full scale range - 0 to :1:199.9 millivolts . automatic zero . automatic polarity . bias current - 3na . dc impcciance - l00md . overvoltage protection - 20v sustained, 50v momentary without damage. . decimal points (3) - illuminate with logic "1", extin- guish with logic "0". accuracy . maximum error -0.05% ofreading:l:l digit . resolution - 0.1 millivolt . t~pera[ure range - 0 to +soc operating -30c to +8soc storage . temperature coefficient - :tsoppm/oc normal mode rejecfion . 4odb @ 60hz common mode rejection . 6odb @ :t200mv conversion rate . external trigger - up to 24 conversions per second . internal trigger - 4 conversions per second . automatic - a new conversion is initiated automatically upon completion of conversion in procc$s; conversion rate wid vary from 24/kc (0 4o/sec depending on input magnitude. . hold and read upon command. conversion time . normal conversion - 42ms max (full scale input) . overload conversion - 62ms max interface signals . dtlittl compatible logic "0" logic "i" in <0.8v >2.0v out <0.4v >2.4v . inputs external trigger - operation in the "external trigger" mode requires that the "external hold" input be a logic "0" or sround. neptive triaer pulses - applying a logical "low" to the "hold" input disables the internal trigger. a negative trigger pulse (logic "i" to logic "0") of 1.0p.s minimum applied to the "ext trigger" in- put will initiate conversion in the same manner as the internal oscillator. the external trigger should not be repeated, however, until the "status" indicates com- pletion of the convetsion in process. positive trigger pulses - the "hold" input can be . used to trigger the ad20 1 0 from a "normally low" signal with the "ext trigger" input open or logic "1". following a "hold" a new reading will be initiated on the leading edge of the "hold" signal thus, a mo~ntary positive pulse on the "hold" input can be used to trigger the ad201o. the drift correct interval, how- ever, begins on the trailing edge of the positive pulse, so if [he pulse width exceeds 1ms, the conversion will actually be initiated by the internal trigger. specifications subject to ebanje without notice. maximum conversion rate - automatic - the ad2010 can also be connected for automatic conversion at its maximum conversion rare by connecting the "status" output back into the "hold" input. in this manner the status signal going high at the end of one conversion immediately initiates a new conversion. the pu!$es appearing on the status line can be used to step a multiplexer directly, since the built-in drift-correct delay of 8.33ms will arow settling of the input prior to convctsion. a logic "0" applied to the "ext trigger" will inhibit [he automatic trigger mode. extetnal hold - logic "0" or ground applied to this in. put disables the internal trigger an~ the last conversion is held and displayed. for a new conversion under internal control the input must be opened or at logic "1", for a new conversion under external control, a positive pulse of less than 1.0ms can be applied (as previously explained). outputs . 3 bcd digits (8421 positive true) .latched - 3ttl loads . overrange -logic "." - latched - 6ttl loads, indicates overrange. . overload .logic "0" indicates overload (>199.9mv) logic "i" -latched. 6ttl loads, indicates. data valid. . polarity - logic "i" -latched - 6ttl loads. indicates positive polarity input. . status -logic "0" - conversion in process logic "i" -latched - 6ttl loads, indicates con- version complete:. power . +sv dc :1:5%, 50oma warm up . essentially none to specified accuracy adjustments . range potentiometer for full scale calibration. calibra- tion recommended every six months. size . 3"w x 1.8mh x 0.84"d (76.2 x 45.7 x 21.3mm) (overall depth for case and printed circuit board extension is 1.40" (35.6mm?. ordering guide . ad2010' standard ad2010 as described above - tuned for peak normal mode rejection at 60hz and its harmonics. weight . 4 oz. (113.sgm) overall dimensions all dimensions are given in inches and (nun). pin "a" pin "s" ,"--' ~0.30t7.62im'n. 1.41 ~ 1 ~ ---, l 0.840 (21.31 max. . --1 11-- .. 3.020 (78.7)'~~. ---j !:tag j3.94} max. i--- -3.420 188.8) max.--j normal mode adjustment (ad201or only) -2- rev. a obsolete
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