Medical device delivery systems that include a distal protection feature are provided. When the AGC voltage is within a predetermined voltage range, the overall gain of the AGC amplifier circuit is varied by the variable-gain amplifier; however, when the AGC voltage is outside the predetermined voltage range, the overall gain is kept constant by the fixed-gain amplifier. The complementary areas of the conducting layer are rendered insulating by oxidation. The supply potentials of the secondary read amplifier are provided so that the secondary read amplifier operates within the amplifying operating range when either of its input terminals is driven to the first logic potential and the other input terminal is driven to the second logic potential.