Datasheet TLV431 (Diodes) - 9

TLV431 Application Notes
(continued)
Printed Circuit Board Layout Considerations
The TLV431 in the SOT25 package has the die attached to pin 2, which results in an electrical contact between pin 2 and pin 5. Therefore, pin 2 of the SOT25 package must be left floating or connected to pin 5. The TLV431 in the SC70-6 (SOT363) package has the die attached to pin 2 and 5, which results in an electrical contact between pins 2, 5, and pin 6. Therefore, pins 2 and 5 must be left floating or connected to pin 6.
Other Applications of the TLV431
R3 Vin Vout  1 R  V  V 1  R4 R1 OUT REF  2 R  ZXTP2039F IB  I VN O V UT  Q1 3 R I  SH B I VREF TLV431 BE V R4  B I C1  I  0.1µF  SH    R2 I mA 15 B  h  ( FE min)   ISH GND
Figure 3. High-Current Shunt Regulator
It may at times be required to shunt-regulate more current than the 15mA that which the TLV431 is capable. Figure 3 shows how this can be done using transistor Q1 to amplify the TLV431’s current. Care must be taken so the power dissipation and/or SOA requirements of the transistor is not exceeded. IOUT ZXTN25020CFH Vin Vout Q1 R3 R1  1 R  V  V 1  OUT REF I  2 R  B   V I VN ( OUT V BE V ) REF 3 R  TLV431 B I  I  OUT(max)   C1  I  mA 15 B  h  ( FE min)   0.1µF R2 GND
Figure 4. Basic Series Regulator
A very effective and simple series regulator can be implemented as shown in Figure 4. This may be preferable if the load requires more current than can be provided by the TLV431 alone, and conserving power when the load is not being powered is required. This circuit also uses one component less than the shunt circuit shown in Figure 3. TLV431 9 of 17 March 2024 Document number: DS32088 Rev. 9 - 2
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