|AD1585||2.5 V to 5.0 V Micropower, Precision Series Mode Voltage References|
|AD1585 Datasheet PDF : 16 Pages |
The AD1582/AD1583/AD1584/AD1585 are series references
that can be used for many applications. To achieve optimum
performance with these references, only two external compo-
nents are required. Figure 10 shows the AD1582/AD1583/
AD1584/AD1585 configured for operation under all loading
conditions. With a simple 4.7 µF capacitor attached to the input
and a 1 µF capacitor applied to the output, the devices can achieve
specified performance for all input voltage and output current
requirements. For best transient response, add a 0.1 µF capacitor
in parallel with the 4.7 µF capacitor. While a 1 µF output capacitor
can provide stable performance for all loading conditions, the
AD1582/AD1583/AD1584/AD1585 can operate under low
(−100 µA < IOUT < +100 µA) current conditions with just a
0.2 µF output capacitor. The 4.7 µF capacitor on the input can
be reduced to 1 μF in this condition.
Unlike conventional shunt reference designs, the AD1582/
AD1583/AD1584/AD1585 provide stable output voltages at
constant operating current levels. When properly decoupled,
as shown in Figure 10, these devices can be applied to any
circuit and provide superior low power solutions.
1µF AD1584/ 3
Figure 10. Typical Connection Diagram
The AD1582/AD1583/AD1584/AD1585 are designed for
applications where temperature performance is important.
Extensive temperature testing and characterization ensure
that device performance is maintained over the specified
The error band guaranteed with the AD1582/AD1583/AD1584/
AD1585 is the maximum deviation from the initial value at 25°C.
Therefore, for a given grade of the AD1582/AD1583/AD1584/
AD1585, the designer can easily determine the maximum total
error by summing initial accuracy and temperature variation. For
example, for the AD1582BRT, the initial tolerance is ±2 mV, and
the temperature error band is ±8 mV; therefore, the reference is
guaranteed to be 2.5 V ± 10 mV from −40°C to +125°C.
Figure 11 shows the typical output voltage drift for the AD1582/
AD1583/AD1584/AD1585 and illustrates the methodology. The
box in Figure 11 is bounded on the x-axis by operating tempera-
ture extremes. It is bounded on the y-axis by the maximum
and minimum output voltages observed over the operating
temperature range. The slope of the diagonal drawn from the
initial output value at 25°C to the output values at +125°C and
−40°C determines the performance grade of the device.
Duplication of these results requires a test system that is highly
accurate with stable temperature control. Evaluation of the
AD1582/AD1583/AD1584/AD1585 produces curves similar
to those in Figure 5 and Figure 11, but output readings can vary
depending on the test methods and test equipment used.
–40 –20 0
20 40 60 80 100 120
Figure 11. Output Voltage vs. Temperature
VOLTAGE OUTPUT NONLINEARITY VS.
When using a voltage reference with data converters, it is
important to understand the impact that temperature drift can
have on converter performance. The nonlinearity of the reference
output drift represents additional error that cannot be easily
calibrated out of the overall system. To better understand the
impact such a drift can have on a data converter, refer to Figure 12,
where the measured drift characteristic is normalized to the
endpoint average drift. The residual drift error for the AD1582/
AD1583/AD1584/AD1585 of approximately 200 ppm demon-
strates that these parts are compatible with systems that require
12-bit accurate temperature performance.
Figure 12. Residual Drift Error
Rev. J | Page 11 of 16
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