TL431 Programmable Precision References
FEATURES
lProgrammable Output Voltage to 36 Volts
lLow Dynamic Output Impedance, 0.22 Ω Typical
lSink Current Capability of 1.0 to 100 mA
lEquivalent Full-Range Temperature Coefficient of
50 ppm/oC Typical
lTemperature Compensated for operation over
Full Rated Operating Temperature Range
lLow Output Noise Voltage
TO-92
The TL431 integrated circuits are three-terminal
programmable shunt regulator diodes. These monolithic
IC voltage references operate as a low temperature
coefficient zener which is programmable from Vref to
36 volts with two external resistors. These devices
exhibit a wide operating current range of 1.0 to 100mA
with a typical dynamic impedance of 0.22 Ω. The
characteristics of these references make them
Pin: 1. Reference
2. Anode
3. Cathode
excellent replacements for zener diodes in many
applications such as digital voltmeters, power supplies,
and op amp circuitry. The 2.5 volt reference makes it
convenient to obtain a stable reference from 5.0 volt
logic supplies, and since the TL431 operates as a shunt
regulator, it can be used as either a positive or negative
voltage reference.
PIN ARRANGEMENT
DIP-8
Pin: 1 . Cathode
6. Anode
8. Reference
Other Pins: NC
SOP-8
Pin: 1. Cathode 5. NC
2. Anode 6. Anode
3. Reference 7. Anode
4. NC 8. Reference
This SOP-8 is an internally modified SOP-8 Package.
Pins 2, 3, 6 and 7 are electrically common to the die
attach flag. This internal lead frame modification
decreases package thermal resistance and increases
power dissipation capability when appropriately
mounted on a printed circuit board. This SOP-8
conforms to all external dimensions of the standard
SOP-8 package.
CIRCUIT SCHEMATIC
ORDERING INFORMATION
FUNCTIONAL BLOCK DIAGRAMSYMBOL
Temperature
Device Range Package
TL431CT TO-92
TL431CD 0 to +70 oC DIP-8
TL431CS SOP-8
TL431IT TO-92
TL431ID -40 to +85 oC DIP-8
TL431IS SOP-8
9-1
TL431 Programmable Precision References
Rating Symbol Value Unit
MAXIMUM RATINGS (Full operating ambient temperature range applies unless otherwise noted.)
Cathode to Anode Voltage VKA 37 V
Cathode Current Range, Continuous IK-100 to +150 mA
Reference Input Current Range, Continuous Iref -0.05 to +10 mA
Operating Junction Temperature TJ150 oC
Operating Ambient Temperature Range TAoC
TL431I, TL431AI, TL431BI -40 to +85
TL431C, TL431AC, TL431BC 0 to +70
Storage Temperature Range Tstg -65 to +150 oC
Total Power Dissipation @ TA = 25oCP
DW
Derate above TA = 25oC Ambient Temperature
T, S Suffix Packages 0.70
D Suffix Package 1.10
Total Power Dissipation @ TC = 25oCP
DW
Derate above TA = 25oC Case Temperature
T, S Suffix Packages 1 . 5
D Suffix Package 3 . 0
THERMAL CHARACTERISTICS
Characteristic Symbol T, S Suffix D Suffix Unit
Thermal Resistance, Junction to Ambient Rθ JA 178 114 oC/W
Thermal Resistance, Junction to Case Rθ JC 83 41 oC/W
RECOMMENDED OPERATING CONDITIONS
Condition / Value Symbol Min Max Unit
Thermal Resistance, Junction to Ambient VΚAVref 36 V
Thermal Resistance, Junction to Case IK1.0 100 mA
9-2
TL431 Programmable Precision References
ELECTRICAL CHARACTERISTICS (Ambient temperature at 25oC unless otherwise noted)
TL431I TL431C
Characteristic Symbol Min Typ Max Min Typ Max Unit
Reference Input Voltage (Fig. 1) Vref V
VKA = Vref, IK = 10mA
TA = 25oC 2.44 2.495 2.55 2.44 2.495 2.55
TA = Tlow to Thigh (Note 1) 2.41 - - - 2.58 2.423 --- 2.567
Reference Input Voltage Deviation Over ∆Vref --- 7.0 30 --- 3.0 17 mV
Temperature Range (Fig. 1, Note 1, 2, 4)
VKA = Vref, IK = 10mA
Ratio of Change in Reference Input Voltage ∆Vref mV/V
to Change in Cathode to Anode Voltage ∆VKA
IK = 10mA (Fig. 2),
∆VKA = 10V to Vref --- -1.4 -2.7 --- -1.4 -2.7
∆VKA = 36V to 10V --- -1.0 -2.0 --- -1.0 -2.0
Reference Input Current (Fig. 2) Iref µA
IK = 10mA, R1 = 10k, R2 =
TA = 25oC --- 1.8 4.0 --- 1.8 4.0
TA = Tlow to Thigh (Note 1) - - - - - - 6.5 --- --- 5.2
Reference Input Current Deviation Over ∆Iref --- 0.8 2.5 --- 0.4 1.2 µA
Temperature Range (Fig. 2, Note 1, 4)
IK = 10mA, R1 = 10k, R2 =
Minimum Cathode Current for Regulation Imin --- 0.5 1.0 --- 0.5 1.0 mA
VKA = Vref (Fig. 1)
Off - State Cathode Current (Fig. 3) Ioff --- 260 1000 --- 2.6 1000 nA
VKA = 36V, Vref = 0V
Dynamic Impedance (Fig. 1, Note 3) ZKA --- 0.22 0.5 --- 0.22 0.5 Ω
VKA = Vref, ∆IK = 1.0mA to 100mA,
f < 1.0 kHz
8
8
ELECTRICAL CHARACTERISTICS (Ambient temperature at 25oC unless otherwise noted)
TL431AI TL431AC TL431B
Characteristic Symbol Min Typ Max Min Typ Max Min Typ Max Unit
Reference Input Voltage (Fig. 1) Vref V
VKA = Vref, IK = 10mA
TA = 25oC 2.47 2.495 2.52 2.47 2.495 2.52 2.483 2.495 2.507
TA = Tlow to Thigh (Note 1) 2.44 - - - 2.55 2.453 - -- 2.537 2.475 2.495 2.515
Reference Input Voltage Deviation Over ∆Vref --- 7.0 30 --- 3.0 17 --- 3.0 17 mV
Temperature Range (Fig. 1, Note 1, 2, 4)
VKA = Vref, IK = 10mA
Ratio of Change in Reference Input Voltage ∆Vref mV/V
to Change in Cathode to Anode Voltage ∆VKA
IK = 10mA (Fig. 2),
∆VKA = 10V to Vref --- -1.4 -2.7 --- -1.4 -2.7 --- -1.4 -2.7
∆VKA = 36V to 10V --- -1.0 -2.0 --- -1.0 -2.0 --- -1.0 -2.0
Reference Input Current (Fig. 2) Iref µA
IK = 10mA, R1 = 10k, R2 =
TA = 25oC --- 1.8 4.0 --- 1.8 4.0 --- 1.1 2.0
TA = Tlow to Thigh (Note 1) - - - - - - 6.5 --- - - - 5.2 - - - - - - 4.0
Reference Input Current Deviation Over ∆Iref --- 0.8 2.5 --- 0.4 1.2 --- 0.4 1.2 µA
Temperature Range (Fig. 2, Note 1, 4)
IK = 10mA, R1 = 10k, R2 =
Minimum Cathode Current for Regulation I min --- 0.5 1.0 --- 0.5 1.0 --- 0.5 1.0 mA
VKA = Vref (Fig. 1)
Off - State Cathode Current (Fig. 3) Ioff --- 260 1000 --- 260 1000 --- 230 500 nA
VKA = 36V, Vref = 0V
Dynamic Impedance (Fig. 1, Note 3) ZKA --- 0.22 0.5 --- 0.22 0.5 --- 0.14 0.3 Ω
VKA = Vref, ∆IK = 1.0mA to 100mA,
f < 1.0 kHz
8
8
9-3
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