Abstract: An integrated circuit package holder comprises a recess for a receipt of a removable spare power source such as two miniature cells to be interconnected between two pins of the holder into which two package supply pins are plugged. The holder can further contain, in a hybrid or integrated form, a circuit for detecting a voltage across spare source terminals that is lower than a predetermined discharge threshold, and a circuit for inhibiting a predetermined function in the integrated circuit when a main power source voltage between the supply pins disappears. A cover inserted between the holder and the package can be provided to connect the package pins to the holder pins without soldering, the cover and the package being locked to the holder by means of single pressures.