Datasheet AD581 (Analog Devices) - 6

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AD581 APPLYING THE AD581
The AD581 is easy to use in virtually all precision reference
V+
applications. The three pins are simply: primary supply, ground,
R40 R41
and output, with the case grounded. No external components
Q7 Q20 Q8
are required even for high precision applications; the degree of
Q10 Q11 C52
desired absolute accuracy is achieved simply by selecting the
Q12 Q15 R42 C51
required device grade. The AD581 requires less than 1 mA quies-
10V Q6 Q14 R34
cent current from an operating supply range of 13 V to 30 V.
13V TO 30V Q16 Q13 R37 Q5 C50 +VS R33 R32 R35 VOUT AD581 10V Q3 Q4 GND Q2 Q1
2
R39 R30 R36
00 4- 01 08 Figure 2. Pin Configuration (Bottom View)
R31
04 -0
V–
14 80 An external fine trim may be desired to set the output level to 0 Figure 4. Simplified Schematic exactly 10.000 V within less than a millivolt (calibrated to a main system reference). System calibration may also require a
VOLTAGE VARIATION vs. TEMPERATURE
reference slightly different from 10.00 V. In either case, the Some confusion exists in the area of defining and specifying optional trim circuit shown in Figure 3 can offset the output by reference voltage error over temperature. Historically, references up to ±30 mV (with the 22 Ω resistor), if needed, with minimal have been characterized using a maximum deviation per degree effect on other device characteristics. Celsius; that is, 10 ppm/°C. However, because of nonlinearities
+15V
in temperature characteristics, which originated in standard Zener references (such as S-type characteristics) manufacturers
TRIM MAX R RANGE Δ TCR
opt for the maximum limit error band approach to specify devices.
22Ω ±30mV 3.5ppm/°C 12Ω ±10mV 2.0ppm/°C +V
This technique involves measurement of the output at three,
S 3.9Ω ±5mV 0.6ppm/°C
five, or more different temperatures to guarantee that the output
VOUT AD581 +10V
voltage falls within the given error band. The temperature charac-
6.8kΩ GND
teristic of the AD581 consistently follows the S-curve shown in Figure 5. Three-point measurement of each device guarantees the error band over the specified temperature range.
10kΩ R 10.005
03 0
–15V
4-
4.3kΩ
01 08 Figure 3. Optional Fine Trim Configuration
) (V T 10.000 OUV
05 0 4- 01
9.995
08
–55 –50 –40 –30 –20 –10 0 10 20 30 40 50 60 70 80 90 100 110 120 125 TEMPERATURE (°C)
Figure 5. Typical Temperature Characteristic Rev. C | Page 6 of 12 Document Outline FEATURES FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION PRODUCT HIGHLIGHTS TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION APPLYING THE AD581 VOLTAGE VARIATION vs. TEMPERATURE OUTPUT CURRENT CHARACTERISTICS DYNAMIC PERFORMANCE PRECISION HIGH CURRENT SUPPLY CONNECTION FOR REDUCED PRIMARY SUPPLY THE AD581 AS A CURRENT LIMITER NEGATIVE 10 V REFERENCE 10 V REFERENCE WITH MULTIPLYING CMOS DACs OR ADCs PRECISION 12-BIT DAC REFERENCE OUTLINE DIMENSIONS ORDERING GUIDE