TL43xLI/TL43xLI-Q1 Programmable Shunt Regulators Texas Instruments TL43xLI/TL43xLI-Q1 Programmable Shunt Regulators are three-terminal adjustable shunt regulators with specified thermal stability over applicable automotive, commercial, and military temperature ranges. The output voltage can be set to any value between Vref (approximately 2.495V) and 36V, with two external resistors. These devices have a typical output impedance of 0.3Ω. Active output circuitry provides a very sharp turn-on characteristic, making these devices excellent replacements for Zener diodes in many applications. These applications include onboard regulation, adjustable power and switching power supplies. These devices are a pin-to-pin alternative to the industry standard TL431, with optimized Iref and IIdev performance. The lower Iref and IIdev values enable designers to achieve higher system accuracy and lower leakage current. The TL432LI/TL432LI-Q1 device has precisely the same functionality and electrical specifications as the TL431LI/TL431LI-Q1 device but has a different pinout for the DBZ package.