The LT3008 may be thought of as a higher input voltage, lower noise version of the LT3009. Summarizing the key differences, the LT3008 has a higher maximum VIN (45V vs. LT3009’s 20V), and a higher minimum V_IN (2.0V vs. 1.6V) which is not good for 2xAA or 2xAAA battery powered operations. Lower noise (92µV_RMS vs. 150µV_RMS) is primarily due to the larger output cap (2.2µF vs. 1µF), and an improved Darlington stage in the error amplifier. The 8-lead SOT-23 package also gives the LT3008 improved thermal performance. Both products are offered in a 2mm x 2mm DFN-6 package which has the same thermal resistance as the SOT-23 package.