TL431/TL432
ADJUSTABLE PRECISION SHUNT REGULATOR
Description
The TL431 and TL432 are three terminal adjustable shunt
regulators offering excellent temperature stability and output
current handling capability up to 100mA. The output voltage
may be set to any chosen voltage between 2.5 and 36 volts
by selection of two external divider resistors.
The devices can be used as a replacement for zener diodes
in many applications requiring an improvement in zener
performance. Diodes’ TL431 has the same electrical
specifications as the industry standard ‘431 and is available
in 2 grades with initial tolerances of 1% and 0.5% for the
A and B grades respectively.
Pin Assignments
TL431
(Top View)
CATHODE 1
3 ANODE
REF 2
SOT23
(Top View)
NC
5 ANODE
Features
•
•
Temperature range -40 to +125ºC
Reference Voltage Tolerance at 25°C
•
TL431A: 2.495V
±
1.0%
•
TL431B: 2.495V
±
0.5%
Low Output Noise
0.2Ω Typical Output Impedance
Sink Current Capability: 1mA to 100mA
Adjustable Output Voltage: V
REF
to 36V
All devices are:
•
Totally Lead-Free & Fully RoHS compliant
(Notes 1 & 2)
•
Halogen and Antimony Free. “Green” Device
(Note 3)
Leave floating or
2
connect to pin 5
CATHODE 3
SOT25
(Top View)
CATHODE 1
ANODE 2
ANODE 3
NC 4
SO-8
8 REF
7 ANODE
6 ANODE
5 NC
4 REF
•
•
•
•
•
SO-8 is a future product
Applications
•
•
•
•
Opto-Coupler Linearisers
Shunt Regulators
Improved Zener
Variable Reference
TL432
(Top View)
REF 1
3 ANODE
CATHODE 2
SOT23
Notes:
1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen and Antimony free,
"Green" and Lead-Free.
3. Halogen and Antimony free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and
<1000ppm antimony compounds.
TL431
*SO-8 is a future package
Document number: DS35044 Rev. 6 - 2
1 of 14
www.diodes.com
April 2012
© Diodes Incorporated
TL431/TL432
ADJUSTABLE PRECISION SHUNT REGULATOR
Absolute Maximum Ratings
(Note 4)
Symbol
V
KA
I
KA
I
REF
T
J
T
ST
P
D
Notes:
Parameter
Cathode Voltage
Continuous Cathode Current
Reference Input Current
Operating Junction Temperature
Storage Temperature
SOT23
Power Dissipation (Notes 5, 6)
SOT25
SO-8*
Rating
40
150
-0.050 to +10
+150
-55 to +150
330
500
700
Unit
V
mA
mA
°
°
C
C
mW
4. Operation above the absolute maximum rating may cause device failure. Operation at the absolute maximum ratings, for extended periods, may
reduce device reliability. Unless otherwise stated voltages specified are relative to the ANODE pin.
5. T
J
,
MAX
=150°C.
6. Ratings apply to ambient temperature at 25°C.
Recommended Operating Conditions
Symbol
V
KA
I
KA
T
A
Cathode Voltage
Cathode Current
Operating Ambient Temperature
Parameter
Min
V
REF
1
-40
Max
36
100
+125
Unit
V
mA
°C
TL431
*SO-8 is a future package
Document number: DS35044 Rev. 6 - 2
2 of 14
www.diodes.com
April 2012
© Diodes Incorporated
TL431/TL432
ADJUSTABLE PRECISION SHUNT REGULATOR
Electrical Characteristics
(T
A
= +25°C, unless otherwise noted)
Symbol
V
REF
Parameter
Reference voltage
Test Conditions
V
KA
= V
REF
,
I
KA
= 10mA
V
KA
= V
REF
,
I
KA
= 10mA
TL431A
TL431B
o
T
A
= 0 to 70 C
Min
2.470
2.482
Typ.
2.495
2.495
6
14
14
-1.4
-1
1
0.8
0.8
0.8
0.4
0.05
0.2
380
250
70
Max
2.520
2.507
16
34
34
-2.7
-2
4
1.2
2.5
2.5
0.7
0.5
0.5
Unit
V
V
DEV
ΔV
REF
ΔV
KA
I
REF
ΔI
REF
Deviation of reference voltage over
full temperature range (Note 5)
Ratio of the change in reference
voltage to the change in cathode
voltage
Reference input current
I
REF
deviation over full temperature
range (Note 7)
Minimum cathode current for
regulation
Off-state current
Dynamic output impedance (Note 8)
Thermal Resistance Junction to
Ambient
T
A
= -40 to +85
o
C
T
A
= -40 to +125
o
C
V
KA
= 10V to V
REF
mV
I
KA
= 10mA
V
KA
= 36V to 10V
mV/V
µA
µA
I
KA
= 10mA, R1 = 10KΩ, R2 =
∞
I
KA
= 10mA,
R1 = 10KΩ,
R2 =
∞
V
KA
= V
REF
V
KA
= 36V, V
REF
= 0V
V
KA
= V
REF,
f = 0Hz
SOT23
SOT25
SO-8*
o
T
A
= 0 to 70 C
T
A
= -40 to +85
o
C
T
A
= -40 to +125 C
o
I
KA(MIN)
I
KA(OFF)
|Z
KA
|
θ
JA
Notes:
mA
µA
Ω
o
C/W
7. Deviation of V
DEV
, and
ΔI
REF
are defined as the maximum variation of the values over the full temperature range.
The average temperature coefficient of the reference input voltage
αV
REF
is defined as:
Vmax
V
DEV
αV
REF
=
V
REF
@ 25ºC
T2 – T1
X 10
6
ppm/ºC
Vmin
Where:
T2 – T1 = full temperature change.
αV
REF
can be positive or negative depending on whether the slope is
positive or negative.
Notes: 8. The dynamic output impedance, R
Z
, is defined as:
V
DEV
= Vmax - Vmin
Z
KA
=
ΔV
KA
ΔI
KA
T1
Temperature
T2
When the device is programmed with two external resistors R1 and R2, the dynamic output
impedance of the overall circuit, is defined as:
Z’ =
ΔV
ΔI
≈
Z
KA
1+
R1
R2
TL431
*SO-8 is a future package
Document number: DS35044 Rev. 6 - 2
3 of 14
www.diodes.com
April 2012
© Diodes Incorporated
TL431/TL432
ADJUSTABLE PRECISION SHUNT REGULATOR
Test Circuits
Figure 1. Test circuit for V
KA
= V
REF
Figure 2. Test circuit for V
KA
> V
REF
Figure 3. Test circuit for I
OFF
TL431
*SO-8 is a future package
Document number: DS35044 Rev. 6 - 2
4 of 14
www.diodes.com
April 2012
© Diodes Incorporated
TL431/TL432
ADJUSTABLE PRECISION SHUNT REGULATOR
Typical Performance Characteristics
2600
2580
V
REF
Reference Voltage (mV)
I
KA
= 10mA
V
KA
= V
REF
T
A
= 25
°
C
0.2
R1 = 10K
Ω
R2 =
∞
I
KA
= 10mA
I
REF
Reference Current (
μ
A)
2560
2540
2520
2500
2480
2460
2440
2420
2400
-55 -35
0.15
0.1
0.05
-15
5
25 45
65 85 105 125
T
A
Free Air Temperature (
°
C)
Reference Voltage vs. Free Air Temperature
0
-55
-15
5
25 45 65
85 105 125
T
A
Free Air Temperature (
°
C)
Reference Current vs. Free Air Temperature
-35
150
V
KA
= V
REF
T
A
= 25
°
C
200
V
KA
= V
REF
T
A
= 25
°
C
100
I
KA
Cathode Current (mA)
I
KA
Cathode Current (
μ
A)
100
I
KMIN
50
0
0
-50
-100
-2
0
1
2
V
KA
Cathode Voltage (V)
Cathode Current vs. Cathode Voltage
-1
3
-100
-2
0
1
2
V
KA
Cathode Voltage
Cathode Current vs. Cathode Voltage
-1
3
0.50
V
KA
= 36V
-0.2
V
REF
= 0
V
KA
= 3V to 36V
0.45
I
KOFF
Off-State Cathode Current (
μ
A)
-0.3
-0.4
dV
REF
/dV
KA
(mV/V)
0.40
0.35
0.30
0.25
0.20
0.15
0.10
-0.5
-0.6
-0.7
-0.8
-0.9
0.05
0.00
-75
-1.0
-50
75
-25
0
25
50
100 125
T
A
Free Air Temperature (
°
C)
Off-State Cathode Current vs. Free Air Temperature
-50
0
25
50
75
100 125
T
A
Free Air Temperature (C)
Ratio of Delta Reference Voltage to Delta Cathode
Voltage vs. Free Air Temperature
-25
TL431
*SO-8 is a future package
Document number: DS35044 Rev. 6 - 2
5 of 14
www.diodes.com
April 2012
© Diodes Incorporated
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