A　1.2V　rail　to　rail　output　driving　amplifier　used　to　drive　the　hearing　aid　loudspeaker　is　proposed　in　this　paper.　Since　the　linearity　of　the　cascoded　amplifier　degrades　with　the　supply　voltage　decreasing,　a　three-stage　cascaded　amplifier　is　adopted.　For　the　rail　to　rail　output　signal　with　high　linearity,　a　special　folded　class-AB　output　stage　current　control　circuit　is　incorporated　in　the　amplifier.　The　minimum　supply　voltage　can　be　reduced　to　VGS+2|Vdsat|.　Fabricated　with　a　0.18　μm　CMOS　process,　the　amplifier　with　the　loading　resistance　100ohm　achieves　-85dB　THD　while　operating　from　a　1.2V　supply　and　using　a　1kHz　input　sine　wave.　©　2018　IEEE.