TL431B Datasheet, PDF (10/40 Pages) Texas Instruments – ADJUSTABLE PRECISION SHUNT REGULATORS

TL431, TL431A, TL431B, TL432, TL432A, TL432B
ADJUSTABLE PRECISION SHUNT REGULATORS
SLVS543A – AUGUST 2004 − REVISED AUGUST 2004
electrical characteristics over recommended operating conditions, T_A = 25°C (unless otherwise
noted)
Vref
VI(dev)
DV_ref
DV_KA
Iref
II(dev)
Imin
Ioff
|zKA|
PARAMETER
TEST
CIRCUIT
TEST CONDITIONS
Reference voltage
2
VKA = Vref,
IKA = 10 mA
Deviation of reference voltage
over full temperature range
(see Figure 1)
2
VKA = Vref,
IKA = 10 mA,
SOT23-3 and TL432
devices
TA = 0°C to 70°C _{All other devices}
Ratio of change in reference voltage
to the change in cathode voltage
3
IKA = 10 mA
∆VKA = 10 V − Vref
∆VKA = 36 V − 10 V
Reference current
3
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
Deviation of reference current
over full temperature range
(see Figure 1)
3
IKA = 10 mA, R1 = 10 kΩ, R2 = ∞,
TA = 0°C to 70°C
Minimum cathode current
for regulation
2
VKA = Vref
Off-state cathode current
Dynamic impedance (see Figure 1)
4
VKA = 36 V,
Vref = 0
1
IKA = 1 mA to 100 mA, VKA = Vref,
f ≤ 1 kHz
TL431C, TL432C
MIN TYP MAX
2440 2495 2550
UNIT
mV
6
16
mV
4
25
−1.4 −2.7 _mV
−1
−2 V
2
4 µA
0.4 1.2 µA
0.4
1 mA
0.1
1 µA
0.2 0.5 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:
Ť Ť _{ǒ Ǔ} ^{ǒ Ǔ} _aVref
VI(dev)
ppm
°C
+
Vref at 25°C
DT_A
10⁶
Maximum Vref
Minimum Vref
VI(dev)
∆TA
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 Vref or maximum Vref, 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
Ť Ť _aVref
ǒ ^{4 mV} Ǔ
+
2495 mV
70°C
10⁶
[
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:
ǒ Ǔ |z_Ȁ|
+
DV
DI
[
|z_KA|
1
)
R1
R2
Figure 1. Calculating Deviation Parameters and Dynamic Impedance
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