vre114/115/116 precision reference supplies ? very high accuracy: 1.500 v output 150 v ? extremely low drift: 0.8 ppm/c 55c to +125c ? low warm - up drift: 1 ppm typ. ? excellent stability: 6 ppm/1000 hrs. typ. ? excellent line regulation: 3 ppm/v typ. ? hermetic 14 - pin ceramic dip ? military processing option description applications ? precision a/d and d/a converters ? transducer excitation ? accurate comparator threshold reference ? high resolution servo systems ? digital voltmeters ? high precision test and measurement instruments features selection guide vre114ds rev. c nov 2000 vre114 series precision voltage references provide ultrastable +1.500v (vre114), - 1.500v (VRE115) and 1.500v (vre116) outputs with 150 v initial accuracy and temperature coefficient as low as 0.8 ppm/c over the full military temperature range. this improvement in accuracy is made possible by a unique, proprietary multipoint laser compensation technique developed by thaler corporation. significant improvements have been made in other performance parameters as well, including initial accuracy, warm - up drift, line regulation, and long - term stability, making the vre114 series the most accurate and stable 1.5v reference available. vre114/115/116 devices are available in two operating temperature ranges, - 25c to +85c and - 55c to +125c, and two performance type output temperature operating range max. volt deviation vre114c +1.5v - 25c to +85c 150 v vre114ca +1.5v - 25c to +85c 75 v vre114m +1.5v - 55c to +125c 240 v vre114ma +1.5v - 55c to +125c 120 v VRE115c - 1.5v - 25c to +85c 150 v VRE115ca - 1.5v - 25c to +85c 75 v VRE115m - 1.5v - 55c to +125c 240 v VRE115ma - 1.5v - 55c to +125c 120 v vre116c 1.5v - 25c to +85c 150 v vre116ca 1.5v - 25c to +85c 75 v vre116m 1.5v - 55c to +125c 240 v vre116ma 1.5v - 55c to +125c 120 v grades. all devices are packaged in 14 - pin hermetic ceramic packages for maximum long - term stability. "m" versions are screened for high reliability and quality. superior stability, accuracy, and quality make these references ideal for precision applications such as a/d and d/a converters, high - accuracy test and measurement instrumentation, and transducer ex citation. thaler corporation ? 2015 n. forbes boulevard ? tucson, az. 8574 5 ? (520) 882 - 4000
model c ca m ma parameters min typ max min typ max min typ max min typ max units absolute maximum ratings power supply 13.5 22 * * * * * * v operating temperature - 25 85 * * - 55 125 - 55 125 c storage temperature - 65 150 * * * * * * c short circuit protection continuous * * * output voltage vre114 +1.5 * * * v VRE115 - 1.5 * * * v vre116 1.5 * * * v output voltage errors initial error 300 150 300 150 v warmup drift 2 1 2 1 ppm tmin - tmax 150 75 240 120 v long - term stability 6 * * * ppm/1000hr. noise (.1 - 10hz) 1.0 * * * vpp output current range 10 * * * ma regulation line 3 10 * * * * * * ppm/v load 3 * * * ppm/ma output adjustment range 5 * * * mv temperature coefficient 1 * * * v/c/mv power supply currents vre114 +ps/ - ps 5 7 * * * * * * ma vre116 +ps 7 9 * * * * * * ma VRE115/116 - ps 4 6 * * * * * * ma specifications vre114/115/116 vps =15v, t = 25c, rl = 10k ? unless otherwise noted. notes: *same as c models. 1. using the box method, the specified value is the maximum deviation from the output voltage at 25c over the specified operating temperature range. 2. the specified values are unloaded. electrical (1) (2) vre114ds rev. c nov 2000
typical performance curves vre114ds rev. c nov 2000 temperature o c vre114/115/116c v out vs. temperature v out vs. temperature v out vs. temperature temperature o c vre114/115/116ca temperature o c vre114/115/116m temperature o c vre114/115/116ma v out vs. temperature quiescent current vs. temp temperature o c junction temp. rise vs. output current output current (ma) psrr vs. frequency frequency (hz) vre114/115 vre116 quiescent current vs. temp temperature o c junction temp. rise vs. output current output current (ma) psrr vs. frequency frequency (hz) positive output negative output quiescent current vs. temp temperature o c junction temp. rise vs. output current output current (ma) psrr vs. frequency frequency (hz)
theory of operation the following discussion refers to the schematic below. a fet current source is used to bias a 6.3v zener diode. the zener voltage is divided by the resistor network r1 and r2. this voltage is then applied to the noninverting input of the operational amplifier which amplifies the voltage to produce a 1.500v output. the gain is determined by the resistor networks r3 and r4: g=1 + r4/r3. the 6.3v zener diode is used because it is the most stable diode over time and temperature. the current source provides a closely regulated zener current, which determines the slope of the reference's voltage vs. temperature function. by trimming the zener current, a lower drift over temperature can be achieved. but since the voltage vs. temperature function is nonlinear, this method leaves a residual error over wide temperature ranges. to remove this residual error, thaler corporation has developed a nonlinear compensation network of thermistors and resistors that is used in the vre114 series references. this proprietary network eliminates most of the nonlinearity in the voltage vs. temperature function. by then adjusting the slope, thaler corporation produces a very stable voltage over wide temperature ranges. this network is less than 2% of the overall network resistance so it has a negligible effect on long term stability. discussion of performance application information figure 1 shows the proper connection of the vre114 series voltage reference with the optional trim resistors. when trimming the vre116, the positive voltage should be trimmed first since the negative voltage tracks the positive side. pay careful attention to the circuit layout to avoid noise pickup and voltage drops in the lines. the vre114 series voltage references have the ground terminal brought out on two pins (pin 6 and pin 7) which are connected together internally. this allows the user to achieve greater accuracy when using a socket. voltage references have a voltage drop across their power supply ground pin due to quiescent current flowing through the contact resistance. if the contact resistance was constant with time and temperature, this voltage drop could be trimmed out. when the reference is plugged into a socket, this source of error can be as high as 20ppm. by connecting pin 7 to the power supply ground and pin 6 to a high impedance ground point in the measurement circuit, the error due to the contact resistance can be eliminated. if the unit is soldered into place the contact resistance is sufficiently small that it doesn't effect performance. vre114 vre116 vre114ds rev. c nov 2000
inches millimeter 14 - pin hybrid package top view top view vre116 vre114 (VRE115) gnd ref. gnd nc - ps nc nc nc fine adj. +1.5v ( - 1.5v) fine adj. +ps ( - ps) nc nc nc fine +adj. +1.5v fine +adj. +ps nc nc nc gnd ref. gnd nc - 1.5v fine - adj. fine - adj. - ps dim min max min max dim min max min max e . 480 .500 12.1 12.7 a .120 .155 3.0 4.0 l . 195 .215 4.9 5.4 q .015 .035 0.4 0.9 d . 775 .805 19.7 20.4 q1 n/a .030 n/a 0.7 b . 016 .020 0.4 0.5 c .009 .012 0.2 0.3 b1 .038 .042 0.9 1.0 g1 .290 .310 7.3 7.8 b2 .095 .105 2.4 2.6 s . 085 .105 2.1 2.6 p . 004 .006 0.10 0.15 external connections figure 1 inches millimeter mechanical pin configuration 1. optional fine adjust for approximately 5mv. VRE115 trim pot center tap connects to - 15v. vre114ds rev. c nov 2000
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