? pin and function compatible with ref01 ? very high accuracy: 10.000 v output 0.3 mv ? extremely low drift: 0.5 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 20 terminal ceramic lcc ? military processing option vre210 precision surface mount reference supplies 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 vre210 series precision voltage references provide ultrastable +10.000v outputs with 0.3 mv initial accuracy and temperature coefficient as low as 0.5 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 vre210 series the most accurate and stable 10v surface mount references available. vre210 devices are available in two operating temperature ranges, -25c to +85c and -55c to +125c, and two electrical performance grades. all devices are packaged in 20 terminal ceramic lcc packages for maximum long-term stability. "m" versions are screened for high reliability and quality. type output temperature operating range max. volt deviation VRE210C +10v -25c to +85c 0.6mv VRE210Ca +10v -25c to +85c 0.3mv vre210m +10v -55c to +125c 1.0mv vre210ma +10v -55c to +125c 0.5mv vre210ds rev. c june 1995
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 vre210 +10 * * * v output voltage errors initial error 500 300 800 400 m v warmup drift 2 1 2 1 ppm t min - t max 600 300 1000 500 m v long-term stability 6 * * * ppm/1000hrs noise (.1-10hz) 6 * * * m vpp output current range 10 * * * ma regulation line 3 10 * * * * * * ppm/v load 3 * * * ppm/ma output adjustment range 20 * * * mv temperature coeff. 4 * * * mv/c/mv power supply currents vre210 +ps 5 7 * * * * * * ma vre210 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. (1) (2) vre210ds rev. c june 1995 vps =15v, t = 25c, rl = 10k w unless otherwise noted. electrical specifications
typical performance curves vre210ds rev. c june 1995 temperature o c VRE210C v out vs. temperature temperature o c VRE210Ca 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) temperature o c vre210m v out vs. temperature temperature o c vre210ma v out vs. temperature
theory of operation the following discussion refers to the schematic below. in operation, approximately 6.3 volts is applied to the noninverting input of the op amp. the voltage is amplified by the op amp to produce a 10.000v output. the gain is determined by the networks r1 and r2: g=1 + r2/r1. the 6.3v zener diode is used because it is the most stable diode over time and temperature. the zener operating current is derived from the regulated output voltage through r3. this feedback arrangement provides a closely regulated zener current. this current determines the slope of the references' 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 compensation technique is not well suited for wide temperature ranges. thaler corporation has developed a nonlinear compensation network of thermistors and resistors that is used in the vre series voltage 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. by using highly stable resistors in our network, we produce a voltage reference that also has very good long term stability. discussion of performance vre210 figure 1 application information figure 2 shows the proper connection of the vre210 series voltage references with the optional trim resistors. pay careful attention to the circuit layout to avoid noise pickup and voltage drops in the lines. the vre210 series voltage references have the ground terminal brought out on two pins (pin 9 and pin 10) 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 10 to the power supply ground and pin 9 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 does not effect performance. vre210ds rev. c june 1995
external connections figure 2 mechanical pin configuration ref gnd top view vre210 11 12 13 9 10 18 17 16 15 14 4 5 6 7 8 1 20 19 3 2 nc nc nc nc v in nc nc trim gnd nc nc v out nc nc nc nc nc nc nc 11 12 13 9 10 18 17 16 15 14 4 5 6 7 8 1 20 19 3 2 +15v v out = +10v 10k w ref. gnd. vre210ds rev. c june 1995 a 0.090 0.110 2.29 2.79 b 0.022 0.028 0.56 0.71 d 0.342 0.358 8.68 9.09 d1 0.048 0.052 1.22 1.32 e 0.342 0.358 8.68 9.09 e1 0.045 0.055 1.114 1.40 j 0.010 ref .254 ref h 0.040 ref 1.02 ref l 0.045 0.055 1.14 1.40 dim inches min max max millimeter min
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