ST TS431 User Manual
TS431
Low voltage adjustable shunt reference
Features
■ Low voltage operation: 1.24 to 6 V
■ 2 %, 1 % and 0.5 % voltage precision
■ Wide operating range cathode current: 60 µA
to 30 mA
■ Low output impedance: 0.2 Ω
■ Typically stable for any capacitive loads
■ ESD protection:
– Human body model: 2 kV
– Machine model: 200 V
■ 100 ppm/°C temperature coefficient
Description
The TS431 is a low-voltage, three-terminal,
programmable shunt voltage reference. The
output voltage can be set to any value between
V
(1.24 V) and 6 V with two external resistors.
ref
The TS431 is able to operate at a lower voltage
(1.24 V) and lower cathode current than the
widely used TL431 and TL1431 shunt voltage
reference. When driving an optocoupler, the
TS431 is particularly useful for regulating 3.3 V
switching power supplies.
Z
TO92
(Plastic package)
L
SOT23-5
(Plastic micropackage)
August 2010 Doc ID 5558 Rev 7 1/13
www.st.com
13
Absolute maximum ratings and operating conditions TS431
1 Absolute maximum ratings and operating conditions
Table 1. Absolute maximum ratings
Symbol Parameter Value Unit
V
T
1. T
Table 2. Operating conditions
Cathode to anode voltage 10 V
KA
I
Continuous cathode current range -20 to +40 mA
k
Reference input current range -0.05 to +3 mA
I
ref
= 25 °C with
amb
(1)
625
500
Power dissipation
P
d
TO92 package
SOT23-5 package
Storage temperature range -65 to +150 °C
stg
= 150 °C, T
junction
R
= 200 °C/W for TO92 package and
thJA
R
= 250 °C/W for SOT23-5L package
thJA
mW
Symbol Parameter Value Unit
V
T
Cathode to anode voltage 1.24 to 6 V
KA
I
Cathode current 0.06 to 30 mA
k
Operating free air temperature range -40 to +125 °C
oper
2/13 Doc ID 5558 Rev 7
TS431 Electrical characteristics
2 Electrical characteristics
Table 3. T
= 25°C (unless otherwise specified)
amb
Symbol Parameter Test conditions Min. Typ. Max. Unit
V
ΔV
ΔVref
---------------ΔVka
I
ΔI
I
I
R
1. Limits are 100% production tested at 25°C. Behavior at the temperature range limits is guaranteed through correlation and
by design.
2. See definition below.
Output voltage
ref
ref
= V
V
KA
@ Ik = 100μA
ref
Output voltage change
Ik = 100μA, VKA = V
ref
(1) (2)
Ratio of change in reference input
voltage to change in cathode to
anode voltage
Reference input current Ik = 10mA 70 160 nA
ref
Reference input current deviation
ref
over temperature range
Minimum cathode current for
min
regulation
Off-state cathode current VKA = 6V, V
off
Static impedance VKA = V
KA
TS431
TS431A
TS431B
0 < T
-40 < T
-40 < T
-40 < T
= 10mA
I
k
V
KA
I
=10mA, R1=10kΩ, R2=∝
k
-40 < T
-40 < T
V
KA
< +70°C
amb
< +85°C
amb
< +105°C
amb
< +125°C
amb
= 6V to V
= V
ref
< +85°C
amb
< +125°C
amb
ref
= 0 0.001 0.1 μA
ref
, Ik = 0.1 to 15mA 0.2 0.4 Ω
ref
1.215
1.228
1.234
1.240 1.265
1.252
1.246
9
16
18
21
1.8 2.7 mV/V
70
90
160
240
40 60 μA
mV
nA
V
2.1 Definition of output voltage change over temperature range
ΔV
is defined as the difference between the maximum and minimum values obtained over
ref
the full temperature range.
ΔV
= V
ref
Figure 1. Output voltage change over temperature range
Vref max.
Vref min.
ref max
- V
ref min
T1
T2
Temperature
Doc ID 5558 Rev 7 3/13
Electrical characteristics TS431
Figure 2. Reference voltage vs. temperature Figure 3. Test circuit for VKA = V
1.252
Vka = Vref
Ik = 100 µA
Reference voltage (V)
1.248
1.244
1.24
1.236
1.232
1.228
-40 -20 0 20 40 60 80 100 120
Temperature (°C)
Figure 4. Cathode voltage vs. cathode
current
15
10
5
0
Vka = Vref
T = 25°C
Input
Ik
Vref
Figure 5. Cathode voltage vs. cathode
current
1.5
1
ref
Output
Vka
-5
Ika Cathode current (mA)
-10
-15
-1 -0.5 0 0.5 1 1.5
Vka Cathode voltage (V)
Figure 6. Reference input current vs.
temperature
100
80
60
40
Iref Reference current (nA)
20
0
-40 -20 0 20 40 60 80 100 120
Temperature (°C)
Ik = 10mA
R1 = 10 K
R2 = +
∞
0.5
Vka Cathode voltage (V)
0
0 102030405060
+25°C
-40°C
Ika Cathode current (µA)
+85°C
+125°C
Figure 7. Static impedance vs. temperature
0.4
Ω
0.3
Vka = Vref
Ik = 100µA to 15mA
0.2
0.1
Rka Static Impedance (Ohms)
0
-40 -20 0 20 40 60 80 100 120
Temperature (°C)
4/13 Doc ID 5558 Rev 7
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