SLVS543J − AUGUST 2004 − REVISED DECEMBER 2005
TL431, TL431A, TL431B
TL432, TL432A, TL432B
ADJUSTABLE PRECISION SHUNT REGULATORS
electrical characteristics over recommended operating conditions, T
A
= 25°C (unless otherwise
noted)
PARAMETER
Vref
VI(dev)
DV
ref
DV
KA
Iref
II(dev)
Imin
Ioff
|zKA|
Reference voltage
Deviation of reference voltage
over full temperature range
(see Figure 1)
Ratio of change in reference voltage
to the change in cathode voltage
Reference current
Deviation of reference current
over full temperature range
(see Figure 1)
Minimum cathode current
for regulation
Off-state cathode current
Dynamic impedance (see Figure 1)
TEST
CIRCUIT
2
2
TEST CONDITIONS
MIN
VKA = Vref,
VKA = Vref,
IKA = 10 mA,
TA = 0°C to 70°C
IKA = 10 mA
IKA = 10 mA
SOT23-3 and TL432
devices
All other devices
∆V
KA = 10 V − Vref
∆V
KA = 36 V − 10 V
2440
TL431C
TL432C
TYP
2495
6
4
−1.4
−1
2
0.4
MAX
2550
16
25
−2.7
−2
4
1.2
mV
V
µA
µA
mV
mV
UNIT
3
3
3
IKA = 10 mA, R1 = 10 kΩ, R2 =
∞
IKA = 10 mA, R1 = 10 kΩ, R2 =
∞,
TA = 0°C to 70°C
VKA = Vref
VKA = 36 V,
Vref = 0
IKA = 1 mA to 100 mA, VKA = Vref,
f
≤
1 kHz
2
4
1
0.4
0.1
0.2
1
1
0.5
mA
µA
Ω
The deviation parameters V
ref(dev)
and I
ref(dev)
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,
α
Vref
, is defined as:
V(
I dev)
V at 25°C
ref
Maximum Vref
a
V
ref
ppm
+
°C
10
6
Minimum Vref
∆T
A
VI(dev)
DT
A
where:
∆T
A
is the recommended operating free-air temperature range of the device.
a
Vref
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
= 2496 mV at 30°C, minimum V
ref
= 2492 mV at 0°C, V
ref
= 2495 mV at 25°C,
∆T
A
= 70°C for TL431C
a
V
+
4 mV
2495 mV
10
6
ref
70°C
[
23 ppm
°C
Because minimum V
ref
occurs at the lower temperature, the coefficient is positive.
Calculating Dynamic Impedance
The dynamic impedance is defined as:
|z
KA
|
+
DV
KA
DI
KA
When the device is operating with two external resistors (see Figure 3), the total dynamic impedance of the circuit
is given by:
|z |
+
DV
[
|z
KA
| 1
)
R1
DI
R2
Figure 1. Calculating Deviation Parameters and Dynamic Impedance
12
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