Data Sheet

LM431SA / LM431SB / LM431SC — Programmable Shunt Regulator
Electrical Characteristics
(7, 8)
(Continued)
Values are at T
A
= 25°C unless otherwise noted.
Notes:
7. T
MIN
= -40°C, T
MAX
= +85°C.
8. The deviation parameters V
REF(dev)
and I
REF(dev)
are defined as the differences between the maximum and minimum
values obtained over the rated temperature range. The average full-range temperature coefficient of the reference
input voltage, αV
REF
, is defined as:
where T
MAX
-T
MIN
is the rated 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: V
REF(dev)
= 4.5 mV, V
REF
= 2500 mV at 25 °C, T
MAX
-T
MIN
= 125 °C for LM431SAI.
Because minimum V
REF
occurs at the lower temperature, the coefficient is positive.
Symbol Parameter Conditions
LM431SAI
Unit
Min. Typ. Max.
V
REF
Reference Input Voltage V
KA
= V
REF
, I
KA
= 10 mA 2.450 2.500 2.550 V
V
REF(dev)
Deviation of Reference
Input Voltage Over-
Temperature
V
KA
= V
REF
, I
KA
= 10 mA,
T
MIN
≤ T
A
≤ T
MAX
520mV
Δ V
REF
/ Δ V
KA
Ratio of Change in
Reference Input Voltage
to Change in Cathode
Voltage
I
KA
= 10 mA
Δ V
KA
= 10 V - V
REF
-1.0 -2.7
mV/V
Δ V
KA
= 36 V - 10 V -0.5 -2.0
I
REF
Reference Input Current I
KA
= 10 mA, R
1
=10 KΩ, R
2
= ∞ 1.5 4.0 μA
I
REF(dev)
Deviation of Reference
Input Current Over Full
Temperature Range
I
KA
= 10 mA, R
1
= 10 KΩ, R
2
= ∞,
T
MIN
≤ T
A
≤ T
MAX
0.8 2.0 μA
I
KA(MIN)
Minimum Cathode
Current for Regulation
V
KA
= V
REF
0.45 1.00 mA
I
KA(OFF)
Off -Stage Cathode
Current
V
KA
= 36 V, V
REF
= 0 0.05 1.00 μA
Z
KA
Dynamic Impedance
V
KA
= V
REF
, I
KA
= 1 to 100 mA,
f ≥ 1.0 kHz
0.15 0.50 Ω
αV
REF
ppm
°C
------------


V
REF dev()
V
REF
at25°C()
--------------------------------------- -


10
6
⋅
T
MAX
T
MIN
–
------------------------------------------------------------
=
αV
REF
4.5mV
2500mV
------------------------


10
6
⋅
125°C
--------------------------------------------
14.4ppm °C⁄==
V
REF(min)
V
REF(max)
T MAX -T MIN
V
REF(dev)
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