high precision, 2.5 v ic reference ad580 rev. b 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 that may result from its use. specifications subject to change without notice. no license is granted by implication or otherwise under any patent or patent ri ghts of analog devices. trademarks and registered trademarks are the property of their respective owners. one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781.329.4700 www.analog.com fax: 781.326.8703 ? 2004 analog devices, inc. all rights reserved. features laser-trimmed to high accuracy: 2.500 v 0.4% 3-terminal device: voltage in/voltage out excellent temperature stability: 10 ppm/c (ad580m, u) excellent long-term stability: 250 v (25 v/month) low quiescent current: 1.5 ma maximum small, hermetic ic package: to-52 can mil-std-883 compliant versions available functional block diagram +e ?e e out 00525-b-001 bottom view figure 1. general description the ad580 is a 3-terminal, low cost, temperature-compensated, bandgap voltage reference, which provides a fixed 2.5 v output for inputs between 4.5 v and 30 v. a unique combination of advanced circuit design and laser-wafer trimmed thin film resistors provide the ad580 with an initial tolerance of 0.4%, a temperature stability of better than 10 ppm/c, and long-term stability of better than 250 v. in addition, the low quiescent current drain of 1.5 ma maximum offers a clear advantage over classical zener techniques. the ad580 is recommended as a stable reference for all 8-, 10-, and 12-bit d/a converters that require an external reference. in addition, the wide input range of the ad580 allows operation with 5 volt logic supplies, making the ad580 ideal for digital panel meter applications or whenever only a single logic power supply is available. the ad580j, k, l, and m are specified for operation over the 0c to +70c temperature range; the ad580s, t, and u are specified for operation over the extended temperature range of C55c to +125c. product highlights 1. laser-trimming of the thin film resistors minimizes the ad580 output error. for example, the ad580l output tolerance is 10 mv. 2. the three-terminal voltage in/voltage out operation of the ad580 provides regulated output voltage without any external components. 3. the ad580 provides a stable 2.5 v output voltage for input voltages between 4.5 v and 30 v. the capability to provide a stable output voltage using a 5 v input makes the ad580 an ideal choice for systems that contain a single logic power supply. 4. thin film resistor technology and tightly controlled bipolar processing provide the ad580 with temperature stabilities to 10 ppm/c and long-term stability better than 250 v. 5. the low quiescent current drain of the ad580 makes it ideal for cmos and other low power applications. 6. the ad580 is available in versions compliant with mil- std-883. refer to the analog devices military products data book or the current ad580/ad883b data sheet for detailed specifications.
ad580 rev. b | page 2 of 8 table of contents specifications ..................................................................................... 3 absolute maximum ratings ............................................................ 4 ad580 chip dimensions and pad layout ............................... 4 esd caution .................................................................................. 4 theory of operation ........................................................................ 5 voltage variation versus temperature ....................................... 5 noise performance ....................................................................... 6 the ad580 as a current limiter .................................................6 the ad580 as a low power, low voltage, precision reference for data converters .......................................................................7 outline dimensions ..........................................................................8 ordering guide .............................................................................8 revision history 8/04changed from rev. a to rev. b updated format................................................................ universal
ad580 rev. b | page 3 of 8 specifications table 1. v in = 15 v and 25c ad580j ad580k ad580l ad580m model min typ max min typ max mi n typ max min typ max units output voltage tolerance error from nominal 2.500 v output 75 25 10 10 mv output voltage change t min to t max 15 7 4.3 1.75 mv 85 40 25 10 ppm/c line regulation 7 v v in 30 v 1.5 6 1 1.5 4 2 2 mv 4.5 v v in 7 v 0.3 3 0.3 2 1 1 mv load regulation ?i = 10 ma 10 10 10 10 mv quiescent current 1.0 1.5 1.0 1.5 1.0 1.5 1.0 1.5 ma noise (0.1 hz to 10 hz) 8 8 8 8 v p-p stability long term 250 250 250 250 v per month 25 25 25 25 v temperature performance specified 0 +70 0 +70 0 +70 0 +70 c operating C55 +125 C55 +125 C55 +125 C55 +125 c storage C65 +175 C65 +175 C65 +175 C65 +175 c package option 2 to-52 (h-03a) ad580jh AD580KH ad580lh ad580mh table 2. ad580s ad580t ad580u model min typ max min typ max min typ max units output voltage tolerance error from nominal 2.500 v output 25 1 10 10 mv output voltage change t min to t max 25 11 4.5 mv 55 25 10 ppm/c line regulation 7 v v in 30 v 1.5 6 2 2 mv 4.5 v v in 7 v 0.3 3 1 1 mv load regulation ?i = 10 ma 10 10 10 mv quiescent current 1.0 1.5 1.0 1.5 1.0 1.5 ma noise (0.1 hz to 10 hz) 8 8 8 v p-p stability long term 250 250 250 v per month 25 25 25 v temperature performance specified C55 +125 C55 +125 C55 +125 c operating C55 +150 C55 +150 C55 +150 c storage C65 +175 C65 +175 C65 +175 c package option 2 to-52 (h-03a) ad580sh ad580th ad580uh 1 specifications shown in boldface are tested on all production units at final electrical test. results from those tests are used to calculate outgoing quality l evels. all min and max specifications are guaranteed, although only those shown in boldface are tested on all production units. 2 h = metal can.
ad580 rev. b | page 4 of 8 absolute maximum ratings table 3. parameter rating input voltage 40 v power dissipation @ 25c ambient temperature 350 mw derate above 25c 2.8 mw/c lead temperature (soldering 10 sec) 300c thermal resistance junction-to-case 100c junction-to-ambient 360c/w stresses above those listed under absolute maximum ratings may cause permanent damage to the device. this is a stress rating only; functional operation of the device at these or any other conditions above those listed in the operational sections of this specification is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. ad580 chip dimensions and pad layout dimensions shown in inches and (millimeters). 00525-b-002 *both e out pads must be connected to the output. 0.075 (1.90) e out * ?e +e 0.046 (1.16) figure 2. the ad580 is also available in chip form. consult the factory for specifications and applications information. esd caution esd (electrostatic discharge) sensitive device. electros tatic charges as high as 4000 v readily accumulate on the human body and test equipment and can discharge wi thout detection. although this product features proprietary esd protection circuitry, permanent dama ge may occur on devices subjected to high energy electrostatic discharges. therefore, proper esd precautions are recommended to avoid performance degradation or loss of functionality.
ad580 rev. b | page 5 of 8 theory of operation the ad580 family (ad580, ad581, ad584, ad589) uses the bandgap concept to produce a stable, low temperature coef- ficient voltage reference suitable for high accuracy data acqui- sition components and systems. the device makes use of the underlying physical nature of a silicon transistor base-emitter voltage in the forward-biased operating region. all such tran- sistors have approximately a C2 mv/c temperature coefficient, unsuitable for use directly as a low tc reference. extrapolation of the temperature characteristic of any one of these devices to absolute zero (with an emitter current propor-tional to the absolute temperature), however, reveals that it will go to a v be of 1.205 v at 0 k, as shown in figure 3. thus, if a voltage could be developed with an opposing temperature coefficient to sum with v be to total 1.205 v, a 0 tc reference would result and operation from a single, low voltage supply would be possible. the ad580 circuit provides such a compensating voltage, v1 in figure 4, by driving two transistors at different current densities and amplifying the resulting v be difference (?v be which now has a positive tc). the sum, v z , is then buffered and amplified up to 2.5 v to provide a usable reference-voltage output. figure 5 shows the schematic diagram of the ad580. the ad580 operates as a 3-terminal reference, meaning that no additional components are required for biasing or current setting. the connection diagram, figure 6, is quite simple. 1.5 1.0 1.205 0.5 0 ?273 c ?200 c ?100 c 100 c 0 c 0k 73k 173k 373k 273k 00525-b-003 temperature junction voltage (v) for both devices required compensation voltage? same devices v be vs. temperature for two typical devices (i e t) constant sum = 1.205v figure 3. extrapolated variation of base-emitter voltage with temperature (i e t), and required compensation, shown for two different devices 00525-b-004 r7 r8 r2 r1 i 2 ? i 1 2i 1 = i 1 + i 2 +v in com r4 r5 q2 8a q1 a v 1 = 2 ? v be r 1 r 2 ? v be v be (q1) v out = v z 1 + = 2.5v r 4 r 5 = v be + 2 ? v be r 1 r 2 = v be + 2 ln r 1 r 2 kt q j 1 j 2 = 1.205v v z = v be + v 1 figure 4. basic bandgap-reference regulator circuit 00525-b-005 com r12 r13 r7 q14 q3 q13 q7 q4 q10 q11 q12 q15 q5 q6 q8 q9 q2 8a q1 a r2 r1 r3 r6 c1 r11 r5 r4 r9 r10 r8 ?e +e 2.5v out figure 5. schematic diagram 00525-b-006 +e 4.5 v in 30v ?e e out load ad580 figure 6. connection diagram voltage variation versus temperature some confusion exists in the area of defining and specifying reference voltage error over temperature. historically, references are characterized using a maximum deviation per degree centigrade; i.e., 10 ppm/c. however, because of the inconsistent nonlinearities in zener references (butterfly or s type characteristics), most manufacturers use a maximum limit error band approach to characterize their references. this technique measures the output voltage at 3 to 5 different temperatures and guarantees that the output voltage deviation will fall within the guaranteed error band at these discrete temperatures. this approach, of course, makes no mention or guarantee of performance at any other temperature within the operating temperature range of the device.
ad580 rev. b | page 6 of 8 the consistent voltage versus temperature performance of a typical ad580 is shown in figure 7. note that the characteristic is quasi-parabolic, not the possible s type characteristics of classical zener references. this parabolic characteristic permits a maximum output deviation specification over the devices full operating temperature range, rather than just at 3 to 5 discrete temperatures. 2.51 2.50 2.49 2.48 2.47 2.46 ?55 ?30 0 25 50 75 100 125 00525-b-007 temperature ( c) output voltage (v) maximum voltage change from 0 c to 70 c figure 7. typical ad580k output voltage vs. temperature the ad580m guarantees a maximum deviation of 1.75 mv over the 0c to 70c temperature range. this can be shown to be equivalent to 10 ppm/c average maximum; i.e., average cppm v c m v max/10 5.2 1 70 ma x 75.1 = the ad580 typically exhibits a variation of 1.5 mv over the power supply range of 7 v to 30 v. figure 8 is a plot of ad580 line rejection versus frequency. noise performance figure 9 represents the peak-to-peak noise of the ad580 from 1 hz (3 db point) to a 3 db high end shown on the horizontal axis. peak-to-peak noise from 1 hz to 1 mhz is approximately 600 v. 140 130 0 10 20 30 40 50 60 70 80 90 100 110 120 10 100 1k 10k 100k 00525-b-008 line frequency (hz) e out , p-p (mv) ad580 k e out p-p e = 23v p-p e = 18.5v e in composite (17v v in 30v) figure 8. ad580 line rejection plot 1mv 100 v 10 v 0 100 1k 10k 100k 1m 00525-b-009 frequency (hz) peak-to-peak noise figure 9. peak-to-peak output noise vs. frequency 00525-b-010 5v 500 a figure 10. input current vs. input voltage (integral loads) the ad580 as a current limiter the ad580 represents an excellent alternative to current limiter diodes that require factory selection to achieve a desired current. this approach often results in temperature coefficients of 1%/c. the ad580 approach is not limited to a specially selected factory set current limit; it can be programmed from 1 ma to 10 ma with the insertion of a single external resistor. the approximate temperature coefficient of current limit for the ad580 used in this mode is 0.13%/c for i lim = 1 ma and 0.01%/c for i lim = 13 ma (see figure 11). figure 10 displays the high output impedance of the ad580 used as a current limiter for i lim = 1, 2, 3, 4, and 5 ma. 00525-b-011 bottom view of 2.5v precision reference circuit in to-52 case ad580 v+ v? output r load 2.5v 2.5v r i ? + 1ma figure 11. a two-component precision current limiter
ad580 rev. b | page 7 of 8 the ad580 as a low power, low voltage, precision reference for data converters the ad580 has a number of features that make it ideally suited for use with a/d and d/a data converters used in complex microprocessor-based systems. the calibrated 2.500 v output minimizes user trim requirements and allows operation from a single, low voltage supply. low power consumption (1 ma quiescent current) is commensurate with that of cmos-type devices, while the low cost and small package complements the decreasing cost and size of the latest converters. figure 12 shows the ad580 used as a reference for the ad7542 12-bit cmos dac with complete microprocessor interface. the ad580 and the ad7542 are specified to operate from a single 5 v supply, thus eliminating the need to provide a 15 v power supply for the sole purpose of operating a reference. the ad7542 includes three 4-bit data registers, a 12-bit dac register, and address decoding logic. it may thus be interfaced directly to a 4-, 8- or 16-bit data bus. only 8 ma of quiescent current from the single 5 volt supply is required to operate the ad7542 which is packaged in a small, 16-pin dip. the ad544 output amplifier is also low power, requiring only 2.5 ma quiescent current. its laser-trimmed offset voltage preserves the 1/2 lsb linearity of the ad7542kn without user trims, and it typically settles to 1/2 lsb in less than 3 s. it will provide the 0 v to C2.5 v output swing from 5 v supplies. 00525-b-012 7 d0 6 d1 5 d2 4 d3 ad7542 clr 13 from system reset from address bus a0 10 a0 a1 11 a1 wr 9 from wr cs 812 3 15 14 16 1 2 from address decoder ad7 ad0 system 8-bit data bus ad544l dgnd ?5v analog input agnd i out2 i out1 rfb v ref v dd 22pf 200 ? 500 ? gain adjust e out +e +5v ?e ad580 figure 12. low power, low voltage reference for the ad7542 microprocessor-compatible, 12-bit dac
ad580 rev. b | page 8 of 8 outline dimensions controlling dimensions are in inches; millimeters dimensions (in parentheses) are rounded-off inch equivalents for reference only and are not appropriate for use in design 0.250 (6.35) min 0.150 (3.81) 0.115 (2.92) 0.050 (1.27) max 0.019 (0.48) 0.016 (0.41) 0.021 (0.53) max 0.030 (0.76) max base & seating plane 0.195 (4.95) 0.178 (4.52) 0.230 (5.84) 0.209 (5.31) 0.500 (12.70) min 0.046 (1.17) 0.036 (0.91) 0.048 (1.22) 0.028 (0.71) 0.050 (1.27) t.p. 3 1 0.100 (2.54) t.p. 0.050 (1.27) t.p. 45 t.p. 2 figure 13. toC52 package dimensions shown in inches and (millimeters) ordering guide model output voltage tolerance temperature coefficient operating temperature range package option package description ad580jh 75 mv 85 ppm/c C55c to +125c toC52 h (metal can) AD580KH 25 mv 40 ppm/c C55c to +125c toC52 h (metal can) ad580lh 10 mv 25 ppm/c C55c to +125c toC52 h (metal can) ad580lmh 10 mv 10 ppm/c C55c to +125c toC52 h (metal can) ad580sh 25 mv 55 ppm/c C55c to +125c toC52 h (metal can) ad580sh/883b 25 mv 55 ppm/c C55c to +125c toC52 h (metal can) ad580th 10 mv 25 ppm/c C55c to +125c toC52 h (metal can) ad580uh 10 mv 10 ppm/c C55c to +125c toC52 h (metal can) ad580uh/883b 10 mv 10 ppm/c C55c to +125c toC52 h (metal can) ad580tchips 10 mv die ? 2004 analog devices, inc. all rights reserved. trademarks and registered trademarks are the prop erty of their respective owners. c00525-0-8/04(b)
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