The LDO series (Low Dropout) TPS80 from Texas Instruments (www.ti.com) can provide output voltages from 1.5 to 54.2 V fixed or adjustable from 1.22 to 5.25 V with maximum current 150 mA output. The voltage drop is only 200 mV with 200 mA of output current. The power consumed is extremely low, with a current of only 500 nA. The circuit is stable with 1 uF ceramic capacitors and in addition it has both thermal protection and overcurrent protection. The integrated circuit enclosures can be either TSOT23-5 or SQN-5. Another important feature is the selection of two output voltage levels, which allows designers to direct the design of the sources for specific applications. Voltage programming is done by EPROM. Readers interested in more information can obtain the datasheet directly from the Texas Instruments website. In figure 1 we have the diagram for an adjustable regulator, with the formula for calculating the components that program the output voltage.
