PROGRAMMABLE PRECISION SHUNT REGULATOR
TL431/A/C
The deviation parameters
ΔV
REF
/ΔT
and
ΔI
REF
/ΔT
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 :
V
I(dev)
(
) × 10
6
V at 25
℃
αV
REF
(ppm/
℃
) =
REF
ΔT
A
Where :
ΔT
A
is the recommended operating free-air temperature range of the device.
αV
REF
can be positive or negative, depending on whether minimum V
REF
or maximum V
REF
, respectively, occurs at
the lower temperature.
Example : Maximum V
REF
=2496mV at 30
℃
, maximum V
REF
=2492mV at 0
℃
, V
REF
=2495mV at 25
℃
,
ΔT
A
=70
℃
for TL431C.
αV
REF
4mV
) × 10
6
= 2495mV
≈
23ppm/
℃
70
℃
(
Because minimum V
REF
occurs at the lower temperature, the coefficient is positive.
Calculating Dynamic Impedance
The dynamic impedance is defined as :
Z
KA
=
ΔV
KA
ΔI
KA
When the device is operating with two external resistors, the total dynamic impedance of the circuit is given by:
Z
'
=
ΔV
≈
Z
KA
(
1 + R1/R2
)
ΔI
Dec. 2010 – Rev.1.5
-6-
HTC
HTC [ HTC KOREA TAEJIN TECHNOLOGY CO. ]
