The MAX97001 mono audio subsystem combines a mono speaker amplifier with a stereo headphone amplifier and an analog DPST switch. The headphone and speaker amplifiers have independent volume control and on/off control. The 4 inputs are configurable as 2 differential inputs or 4 single-ended inputs. The entire subsystem is designed for maximum efficiency. The high-efficiency, 700mW, Class D speaker amplifier operates directly from the battery and consumes no more than 1FA in shutdown mode. The Class H headphone amplifier utilizes a dual-mode charge pump to maximize efficiency while outputting a groundreferenced signal that does not require output coupling capacitors.