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REF3025AIDBZR 参数 Datasheet PDF下载

REF3025AIDBZR图片预览
型号: REF3025AIDBZR
PDF下载: 下载PDF文件 查看货源
内容描述: 50PPM /℃ , 50uA的在SOT23-3 CMOS电压基准 [50ppm/C Max, 50UA in SOT23-3 CMOS VOLTAGE REFERENCE]
分类和应用:
文件页数/大小: 14 页 / 412 K
品牌: BB [ BURR-BROWN CORPORATION ]
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The REF30xx features a low quiescent current, which is  
extremely stable over changes in both temperature and  
supply. The typical room temperature quiescent current is  
42µA, and the maximum quiescent current over temperature  
is just 59µA. Additionally, the quiescent current typically  
changes less than 2.5µA over the entire supply range, as  
shown in Figure 3.  
THEORY OF OPERATION  
The REF30xx is a series, CMOS, precision bandgap voltage  
reference. Its basic topology is shown in Figure 1. The  
transistors Q1 and Q2 are biased such that the current  
density of Q1 is greater than that of Q2. The difference of the  
two base-emitter voltages, Vbe1 Vbe2, has a positive  
temperature coefficient and is forced across resistor R1. This  
voltage is gained up and added to the base-emitter voltage  
of Q2, which has a negative coefficient. The resulting output  
voltage is virtually independent of temperature. The curvature  
of the bandgap voltage, as seen in the typical curve, Output  
Voltage vs Temperature,is due to the slightly nonlinear  
temperature coefficient of the base-emitter voltage of Q2.  
Supply voltages below the specified levels can cause the  
REF30xx to momentarily draw currents greater than the  
typical quiescent current. Using a power supply with a fast  
rising edge and low output impedance easily prevents this.  
SUPPLY CURRENT vs INPUT VOLTAGE  
42.5  
42.0  
41.5  
41.0  
40.5  
40.0  
R1  
+
+
Vbe1 Vbe2  
Q1  
Q2  
1
1.5  
2
2.5  
3
3.5  
4
4.5  
5
5.5  
6
V
IN (V)  
FIGURE 3. Supply Current vs Supply Voltage.  
FIGURE 1. Simplified Schematic of Bandgap Reference.  
THERMAL HYSTERESIS  
APPLICATION INFORMATION  
Thermal hysteresis for the REF30xx is defined as the change  
in output voltage after operating the device at 25°C, cycling  
the device through the specified temperature range, and  
returning to 25°C, and can be expressed as:  
The REF30xx does not require a load capacitor, and is stable  
with any capacitive load. Figure 2 shows typical connections  
required for operation of the REF30xx. A supply bypass  
capacitor of 0.47µF is recommended.  
absVPRE VPOST  
VHYST  
=
106 ppm  
(
)
VNOM  
Where: VHYST = Calculated hysteresis  
VPRE = Output voltage measured at 25°C pre-  
VIN  
1
temperature cycling  
0.47µF  
3
REF30xx  
VPOST = Output voltage measured when device has  
been operated at 25°C, cycled through specified  
range 40°C to +125°C and returned to operation at  
25°C.  
VOUT  
2
TEMPERATURE DRIFT  
FIGURE 2. Typical Connections for Operating REF30xx.  
The REF30xx is designed to exhibit minimal drift error, defined  
as the change in output voltage over varying temperature.  
Using the boxmethod of drift measurement, the REF30xx  
features a typical drift coefficient of 20ppm from 0°C to 70°C—  
the primary temperature range of use for many applications.  
For industrial temperature ranges of 40°C to 125°C, the  
REF30xx family drift increases to a typical value of 50ppm.  
SUPPLY VOLTAGE  
The REF30xx family of references features an extremely low  
dropout voltage. With the exception of the REF3012, which  
has a minimum supply requirement of 1.8V, the REF30xx  
can be operated with a supply of only 1mV above the output  
voltage in an unloaded condition. For loaded conditions, a  
typical dropout voltage versus load is shown on the cover  
page.  
REF3012, 3020, 3025, 3030, 3033, 3040  
8
SBVS032E  
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