Datasheet AD589 (Analog Devices) - 5

AD589 UNDERSTANDING THE SPECIFICATIONS Dynamic Performance Voltage Variation Versus Temperature
Many low power instrument manufacturers are becoming increas- Some confusion exists in the area of defi ning and specifying ingly concerned with the turn-on characteristics of the components reference voltage error over temperature. Historically, references being used in their systems. Fast turn-on components often enable have been characterized using a maximum deviation per degree the end user to keep power off when not needed and yet respond Centigrade, i.e., 10 ppm/°C. However, because of nonlinearities quickly when the power is turned on for operation. Figure 3 dis- in temperature characteristics, which originated in standard Zener plays the turn-on characteristics of the AD589. This characteristic references (such as S type characteristics), most manufacturers is generated from cold-start operation and represents the true turn- have begun to use a maximum limit error band approach to specify on waveform after an extended period with the supplies off. The devices. This technique involves measurement of the output at fi gure shows both the coarse and fi ne transient characteristics of 3, 5, or more different temperatures to guarantee that the output the device; the total settling time to within ±1 mV is about 25 s, voltage will fall within the given error band. The temperature and there is no long thermal tail appearing after that point. characteristics of the AD589 consistently follows the curve shown in Figure 1. Three-point measurement guarantees the error band over the specifi ed temperature range. The temperature coeffi cients
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specifi ed in the Specifi cations section represent the slopes of the
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diagonals of the error band from 25°C to TMIN and 25°C to TMAX.
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Figure 1. Typical AD589 Temperature Characteristics
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Figure 4. Schematic Diagram
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Figure 2. Noise Spectral Density –4– REV. C Document Outline FEATURES PRODUCT DESCRIPTION FUNCTIONAL BLOCK DIAGRAMS PRODUCT HIGHLIGHTS SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS AD589 CHIP DIMENSIONS AND PAD LAYOUT ORDERING GUIDE UNDERSTANDING THE SPECIFICATIONS Voltage Variation Versus Temperature Dynamic Performance APPLICATION INFORMATION OUTLINE DIMENSIONS Revision History