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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 :
Where :
ΔTA 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=2496㎷ at 30℃, maximum VREF=2492㎷ at 0℃, VREF=2495㎷ at 25℃, ΔTA=70℃
for TL431CZ
Because minimum VREF occurs at the lower temperature, the coefficient is positive.
Calculating Dynamic Impedance
The dynamic impedance is defined as :
When the device is operating with two external resistors (see Figure 3), the total dynamic impedance of the circuit
is given by :
Figure 1. Calculating deviation parameters and dynamic impedance
Jan. 2007 - Rev 1.0
HTC
6
70℃
4㎷
2495㎷
x10
6
)
(
|αVREF|=
~ 23PPM/℃
x10
6
VI(dev)
VREFat 25℃
)
(
|αVREF|
ΔTA
ppm
℃
=
)
(
ΔV
ΔI
(1+
)
R1
R2
|Z'|=
~|ZKA|
ΔVKA
ΔIKA
|ZKA|=
ΔTA
VI(dev)
Maximum VREF
Minimum VREF
~
~