TL431A Adjustable Precision Shunt Regulator
1
FEATURES
• Programmable Output Voltage to 36V
• Low Dynamic Output Impedance 0.2Ω
• Sink Current Capability of 0.1 mA to 100 mA
• Equivalent Full-Range Temperature Coefficient of 50 ppm/oC
• Temper atu re Compensated f o r Operation over Full Rated
Operati ng Temp er ature Range
• Low Output Noise Voltage
• Fast Turn on Response
DESCRIPTION
The TL431A is a three-terminal adjustable regulator series with a guaranteed thermal stability over applicable temperature ranges.
The output voltage may be set to any value between Vref (approxim ately 2.5 volts) and 36 volts with two external resistors. These
devices have a typical dynamic output impedance of 0.2Ω. Active output circuitry provides a very sharp turn-on characteristic,
making these devices excellent replacement for zener diodes in many applications.
The TL431A is characterized for operation from -0oC to +70oC.
SYMBOL FUNCTIONAL BLOCK DIAGRAM
SCHEMATIC DIAGRAM
Wing Shing Computer Components Co., (H.K.)Ltd. Tel:(852)2341 9276 Fax:(852)2797 8153
Homepage: http://www.wingshing.com E-mail: wsccltd@hkstar.com
TO-92
REF
ANODE
CATHODE
SOT-89
REF
ANODE
CATHODE
TL431CLP
TL431CPK
TL431A Adjustable Precision Shunt Regulator
2
ABSOLUTE MAXIMUM RATINGS
(Operating temperature range applies unless otherwise specified)
Characteristic Symbol Value Unit
Cathode Voltage VKA 37 V
Cathode Current Range (Continuous) IK-100 ~ +150 mA
Reference Input Current Range IREF 0.05 ~ +10 mA
Operati ng Temp er ature Range TA0 ~ +70 oC
Storage Temperature Range Tstg -65 ~ +150 oC
RECOMMENDED OPERATING CONDITIONS
Characteristic Symbol Test Condition Min Typ Max Unit
Cathode Voltage VKA VREF 36 V
Cathode Curr ent IK1.0 100 mA
ELECTRICAL CHARACTERISTICS
(TA = 25oC, unless otherwise specified)
Characteristic Symbol Test Condition Min Typ Max Unit
Reference Input Voltage VREF VKA = VREF, IK = 10mA 2.475 2.495 2.515 V
Deviation of Reference Input Voltage
Over-Temperature (Not e 1) VREF(dev) VKA = VREF, IK = 10mA
Tmin ≤ TA ≤ Tmax
317 mV
Ratio of Change in Reference Input
Voltage to the Change in ∆
∆V
VREF
KA IK = 10mA ∆VKA = 10V-VREF -1.4 -2.7 mV/V
Cathode Voltage ∆KKA = 36V- 10V -1.0 -2.0
Reference Input Current IREF IK = 10mA, R1 = 10KΩ, R2 = ∞1,8 4 µA
Deviation of Reference Input Current
Over Full Tem perature Rang e IREF(dev) IK = 10mA, R1 = 10KΩ, R2 = ∞
Ta = Full Range
0.4 1.2 µA
Minimum Cathode Current for
Regulation IK(min) VKA = VREF 0.5 1.0 mA
Off-Stat e C athode Current IK(off) VKA = 36V, VREF = 0 0.26 1.0 µA
Dynamic Impedance (Note2) ZKA VKA = VREF, IK = 10mA to 100mA
f ≤ 1.0KHz
0.22 0.4 Ω
Note: 1. The deviation parameters VREF(dev) and IREF(dev) are defined as the differ ences between the ma ximum and minimum values obt ain ed over the rated
temperature range.
VREF(dev) = VREF(max) - VREF(min)
The equivalent full-range temperature coefficient of the reference
input voltage, αVREF is defined as:
αVREF
( )
ppm
C° =
( )
V
V@C
Ta
REF(dev)
REF °×106
∆
Where ∆TA is the rated opera tin g free-ai r temper atu r e range of
the device.
αVREF can be positive or negative depending on whether minimum VREF or
maximum VREF respectively, occurs at the
lower temperature.
2. The dynamic impedance is defined as:
ZKA = ∆
∆
V
I
KA
K
Wing Shing Computer Components Co., (H.K.)Ltd. Tel:(852)2341 9276 Fax:(852)2797 8153
Homepage: http://www.wingshing.com E-mail: wsccltd@hkstar.com
A
A
A
TL431A Adjustable Precision Shunt Regulator
3
When the d evice is operated wit h two external resistors ( see Figure 2), the total dynamic impedance of the circui t is given by:
Z' = ∆
∆
V
I = ZKA (1+ R
R
1
2)
TEST CIRCUITS
Fig.1. Test Circuit f o r VKA = VREF Fig.2. Test Circuit for VKA ≥
≥≥
≥ VREF
Fig.3. Test Circuit f o r Ioff
PAD LAYOUT
B T 43 1 PAD DIAGRAM
C h ip si ze: 1345 x 990
Pad size :
Unit : m
µ
(0 ,0 )
2
34 1
Wing Shing Computer Components Co., (H.K.)Ltd. Tel:(852)2341 9276 Fax:(852)2797 8153
Homepage: http://www.wingshing.com E-mail: wsccltd@hkstar.com
TL431A Adjustable Precision Shunt Regulator
4
PAD LOCATION
Unit: µm
Pad No. Pad Name Description X Y
1 R Reference 235 400
2 K Cathode -505 343.5
3 K Cathode -497.5 -346
4 A Anode -177.5 -341.5
Physical Characteristics
Wafes 4» 4» Wafes 460 ± 40 µm
Size 1.35 × 0.99 mm
Scribe width 90 µm
Wafe’s Backside Ti – Ni – Ag: Ti - 0.1 ± 0.02 µm
Ni - 0.5 ± 0.1 µm
Ag - 0.6 ± 0.1 µm
Passivation PSG
Wing Shing Computer Components Co., (H.K.)Ltd. Tel:(852)2341 9276 Fax:(852)2797 8153
Homepage: http://www.wingshing.com E-mail: wsccltd@hkstar.com
