I started working with the LT1990 Differentiel amplifier. In the datasheet, it's stated that he needit needs a 1.25V voltage reference. I made some research and iI found the TLVH431 Low-voltage adjustable precision shunt regulators but iI didn't understand how heit works and how from an input voltage iI can have 1.25V voltage reference ? Can someone explain to me how heit works