LM431
www.ti.com
SNVS020G –MAY 2000–REVISED APRIL 2013
LM431 Electrical Characteristics
T
A
= 25°C unless otherwise specified
Symbol Parameter Conditions Min Typ Max Units
V
REF
Reference Voltage V
Z
= V
REF
, I
I
= 10 mA 2.440 2.495 2.550 V
LM431A (Figure 4 )
V
Z
= V
REF
, I
I
= 10 mA 2.470 2.495 2.520 V
LM431B (Figure 4 )
V
Z
= V
REF
, I
I
= 10 mA 2.485 2.500 2.510 V
LM431C (Figure 4 )
V
DEV
Deviation of Reference Input Voltage Over V
Z
= V
REF
, I
I
= 10 mA, 8.0 17 mV
Temperature
(1)
T
A
= Full Range (Figure 4 )
ΔV
REF
/ΔV
Z
Ratio of the Change in Reference Voltage I
Z
= 10 mA V
Z
from V
REF
to 10V −1.4 −2.7 mV/V
to the Change in Cathode Voltage (Figure 5 )
V
Z
from 10V to 36V −1.0 −2.0
I
REF
Reference Input Current R
1
= 10 kΩ, R
2
= ∞, I
I
= 10 mA 2.0 4.0 μA
(Figure 5 )
∝I
REF
Deviation of Reference Input Current over R
1
= 10 kΩ, R
2
= ∞, I
I
= 10 mA,
0.4 1.2 μA
Temperature T
A
= Full Range (Figure 5 )
I
Z(MIN)
Minimum Cathode Current for Regulation V
Z
= V
REF
(Figure 4 ) 0.4 1.0 mA
I
Z(OFF)
Off-State Current V
Z
= 36V, V
REF
= 0V (Figure 6) 0.3 1.0 μA
r
Z
Dynamic Output Impedance
(2)
V
Z
= V
REF
, LM431A, 0.75 Ω
Frequency = 0 Hz (Figure 4 )
V
Z
= V
REF
, LM431B, LM431C 0.50 Ω
Frequency = 0 Hz (Figure 4 )
(1) Deviation of reference input voltage, V
DEV
, is defined as the maximum variation of the reference input voltage over the full temperature
range.
The average temperature coefficient of the reference input voltage, ∝V
REF
, is defined as:
Where:
T
2
− T
1
= full temperature change (0-70°C).
V
REF
can be positive or negative depending on whether the slope is positive or negative.
Example: V
DEV
= 8.0 mV, V
REF
= 2495 mV, T
2
− T
1
= 70°C, slope is positive.
(2) The dynamic output impedance, r
Z
, is defined as:
When the device is programmed with two external resistors, R1 and R2, (see Figure 5 ), the dynamic output impedance of the overall
circuit, r
Z
, is defined as:
Copyright © 2000–2013, Texas Instruments Incorporated Submit Documentation Feedback 3
Product Folder Links: LM431
