The HT97230 is a differential input Direct Drive line driver/headphone amplifier, which can also drive single-ended input signal. It is capable of driving line level loads with 3VRMS into 1kΩ with a 5V supply and 2VRMS into 600Ω loads from a 3.3V supply. A headphone load is capable of being driven with 125mW into 32Ω with a 5V supply.

The IC performs excellent 3D surround technology realizing natural surround sound field regarded center orientation. The IC also integrates dynamic bass boost technology to provide graceful bass sound with low distortion. Both 3D surround and bass boost function is adjustable through external resistors and capacitors.

The IC is offered with an externally set gain through external resistors (or an inter­nally fixed 6dB gain which needs to be pre-booked. The external gain setting nodes can also be used to configure filters for set-top box applica­tions. The IC has exceptional THD+N over the full audio bandwidth.

Two versions of the IC can be chosen with different turn-on times (tON). The versions for headphone applications feature a tON of 5.5ms while the version, intended for set-top-box applications, which needs to be pre-booked, feature a 130ms tON. An on-chip charge pump inverts the power-supply input, creating a negative rail. The output stage of the amplifier is powered between the positive input sup­ply and the output of the charge pump. The bipolar sup­plies bias the output about ground, eliminating the need for large, distortion-introducing output coupling capaci­tors. The IC shutdowns and startups without click-pop noise.

The IC is available in a 4mm x 4mm, 24-pin QFN-PP and is specified over the extended -40°C to +85°C temperature range. 20-pin QFN-PP is also available only when pre-booked.