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TL431Z Datasheet, PDF (6/15 Pages) List of Unclassifed Manufacturers – PROGRAMMABLE PRECISION SHUNT REGULATOR | |||
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PROGRAMMABLE PRECISION SHUNT REGULATOR TL431Z/AZ /CZ
The deviation parameters VREF(DEV) and IREF(DEF) are defined as the differences between the maximum and minimum
values obtained over the recommended temperature range. The average full-range temperature coefficient of the
reference voltage, αV REF, is defined as :
ï½Î±VREFï½ï¼
ppm
â
ï¼
ï¼=
VREVF aI(dte2v)5âï¼x106
ÎTA
Maximum VREF
Minimum VREF
VI(dev)
ÎTA
Where :
ÎTA is the recommended operating free-air temperature range of the device.
αVREF can be positive or negative, depending on whether minimum V REF or maximum VREF, respectively, occurs at the
lower temperature.
Example : Maximum VREF=2496ã· at 30â, maximum VREF=2492ã· at 0â, VREF=2495ã· at 25â, ÎTA=70â
for TL431CZ
ï½Î±VREFï½= ï¼ 2449ã·5ã·ï¼x106 ~~ 23PPM/â
70â
Because minimum VREF occurs at the lower temperature, the coefficient is positive.
Calculating Dynamic Impedance
The dynamic impedance is defined
as
:
ï½ZKAï½=
ÎVKA
ÎIKA
When the device is operating with two external resistors (see Figure 3), the total dynamic impedance of the circuit
is given by :
ï½Z'ï½=
ÎV
ÎI
~~ï½ZKAï½ ï¼1+
R1
R2 ï¼
Figure 1. Calculating deviation parameters and dynamic impedance
Jan. 2007 - Rev 1.0
6
HTC
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