functional block diagram 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. a low cost, precision 2.5 v ic references AD1403/AD1403a* one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 617/329-4700 fax: 617/326-8703 product description the AD1403 and AD1403a are improved three-terminal, low cost, temperature compensated, bandgap voltage references that provide a fixed 2.5 v output voltage for inputs between 4.5 v and 40 v. a unique combination of advanced circuit design and laser-wafer-trimmed thin-film resistors provides the AD1403/ AD1403a with an initial tolerance of 10 mv and a tempera- ture stability of better than 25 ppm/ c. in addition, the low quiescent current drain of 1.5 ma (max) offers a clear advan- tage over classical zener techniques. the AD1403 or AD1403a is recommended as a stable refer- ence for all 8-, 10- and 12-bit d-to-a converters that require an external reference. in addition, the wide input range of the AD1403/AD1403a allows operation with 5 volt logic supplies, making these devices ideal for digital panel meter applications and when only a single logic supply is available. the AD1403 and AD1403a are specified for operation over the 0 c to +70 c temperature range. the ad580 series of 2.5 volt precision ic references is recommended for applications where operation over the C55 c to +125 c range is required. * protected by u.s. patent numbers: 3,887,863, re30,586. features improved, lower cost, replacements for standard 1403, 1403a 3-terminal device: voltage in/voltage out laser trimmed to high accuracy: 2.500 v 6 10 mv (AD1403a) excellent temperature stability: 25 ppm/ 8 c (AD1403a) low quiescent current: 1.5 ma max 10 ma current output capability low cost convenient mini-dip package product highlights 1. the AD1403a offers improved initial tolerance over the in- dustry-standard 1403a: 10 mv versus 25 mv at a lower cost. 2. the three-terminal voltage in/voltage out operation of the AD1403/AD1403a provides a regulated output voltage with- out any external components. 3. the AD1403/AD1403a provides a stable 2.5 v output volt- age for input voltages between 4.5 v and 40 v making these devices ideal for systems that contain a single logic supply. 4. thin film resistor technology and tightly controlled bipolar processing provide the AD1403a with temperature stabilities of 25 ppm/ c. 5. the low 1.5 ma maximum quiescent current drain of the AD1403 and AD1403a makes them ideal for cmos and other low power applications.
rev. a C2C AD1403/AD1403aCspecifications characteristic symbol min typ max unit output voltage (i o = 0 ma) v o AD1403 2.475 2.500 2.525 v AD1403a 2.490 2.500 2.510 temperature coefficient of output voltage d v o / d t ppm/ c AD1403 10 40 AD1403a 10 25 output voltage change, 0 c to +70 c d v o mv AD1403 7.0 AD1403a 4.4 line regulation reg in mv (15 v v in 40 v) 1.2 4.5 (4.5 v in 15 v) 0.6 3.0 load regulation reg load 10 mv (0 ma < i o < 10 ma) quiescent current i i 1.2 1.5 ma (i o = 0 ma) specifications subject to change without notice. (v in = 15 v, t a = +25 8 c unless otherwise noted.) maximum ratings (t a = +25 c unless otherwise noted) rating symbol value unit input voltage v in 40 v storage temperature t stg C25 to 100 c junction temperature t j +175 c operating ambient temperature range t a 0 to +70 c ordering guide initial package model tolerance option* AD1403 25 mv n-8 AD1403a 10 mv n-8 *n plastic dip. figure 1. AD1403/AD1403a connection diagram figure 2. simplified AD1403 schematic
AD1403/AD1403a rev. a C3C figure 3. typical change in v out vs. v in (normalized to v out @ v ln = 15 v @ t c = 25 c) figure 4. change in output voltage vs. load current (normalized to v out @ v in = 15 v, l out = 0 ma) figure 5. quiescent current vs. temperature (v in = 15 v, i out = 0 ma) typical performance curvesC figure 6. change in v out vs. temperature (normalized to v out @ v in = 15 v) figure 7. change in v out vs. temperature (normalized to v out @ v ln = 15 v, i out = 0 ma) voltage variation vs. temperature and line some confusion exists in the area of defining and specifying ref- erence voltage error over temperature. historically, references are characterized using a maximum deviation per degree centi- grade; i.e., 10 ppm/ c. however, because of the inconsistent nonlinearities in zener references (butterfly or s type charac- teristics), most manufacturers use a maximum limit error band approach to characterize their references. this technique mea- sures 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 ap- proach, of course, makes no mention or guarantee of perfor- mance at any other temperature within the operating temperature range of the device. the consistent voltage vs. temperature performance of a typi- cal AD1403 is shown in figure 6. note that the characteristic is quasi-parabolic, not the possible s type characteristics of clas- sical 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.
AD1403/AD1403a rev. a C4C c551aC9C7/82 printed in u.s.a. the AD1403 exhibits a worst-case shift of 7.5 mv over the en- tire range of operating input voltage, 4.5 volts to 40 volts. typi- cally, the shift is less than 1 mv as shown in figure 3. the AD1403a as a low power, low voltage precision reference for data converters the AD1403a has a number of features that make it ideally suited for use with a/d and d/a data converters used in com- plex microprocessor-based systems. the calibrated 2.500 volt output minimizes user trim requirements and allows operation from a single low voltage supply. low power consumption (1.5 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 8 shows the AD1403a used as a reference for the ad7524 low-cost 8-bit cmos dac with complete micro- figure 8. low power, low voltage reference for the ad7524 microprocessor-compatible 8-bit dac processor interface. the AD1403a and the ad7524 are speci- fied to operate from a single 5 volt supply; this eliminates the need to provide a +15 volt power supply for the sole purpose of operating a reference. the ad7524 includes an 8-bit data regis- ter, and address decoding logic; it may thus be interfaced di- rectly to an 8- or 16-bit data bus. only 300 m a of quiescent current from the single +5 volt supply is required to operate the ad7524 which is packaged in a small 16-pin dip. the ad542 output amplifier is also low power, requiring only 1.5 ma quies- cent current. its laser-trimmed offset voltage preserves the 1/2 lsb linearity of the ad7524kn without user trims and it typi- cally settles to 1/2 lsb in less than 5 microseconds. it will pro- vide the 0 volt to C2.5 volt output swing from 5 volt supplies. the AD1403 as a precision programmable current source the AD1403 is an excellent building block for precision current sources. its wide range of operating voltages, 4.5 v to 40 v, along with excellent line regulation over that range (7.5 mv) result in high insensitivity to varying load impedances. the low quiescent current (i i ) of 1.5 ma (max) and the maximum speci- fied maximum load current of 10 ma allows the user to pro- gram current to any value between 1.5 ma and 10 ma. figure 9a shows the AD1403 connected as a current source. total current is equal to the quiescent current plus the load current. most of the temperature coefficient comes from the quiescent current term i i , which has a typical tc of 0.13%/ c (1300 ppm/ c). the load voltage (and hence current) tc is much lower at 40 ppm/ c max (AD1403). therefore, the overall temperature coefficient decreases rapidly as the load cur- rent is increased. figure 9b shows the typical temperature coef- ficient for currents between 1.5 ma and 10 ma. use of an AD1403a will not improve the tc appreciably. figure 9a. the AD1403 as a precision programmable current source figure 9b. typical temperature coefficient of current source outline dimensions dimensions shown in inches and (mm). applying the AD1403/AD1403a 8-pin mini-dip (n)
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