Maxim's MAX97220 is a differential-input DirectDrive® line driver/headphone amplifiers
The MAX97220 is a differential-input DirectDrive® line driver/headphone amplifier. This device is capable of driving line level loads with 3 VRMS into 1 kΩ with a 5 V supply and 2 VRMS into 600 Ω loads from a 3.3 V supply. A headphone load is capable of being driven with 125 mW into 32 Ω with a 5 V supply. The IC is offered with an internally-fixed 6 dB gain or an externally-set gain through external resistors. 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 are available with different turn-on times (tON). The A, C, and E versions for headphone applications feature a tON of 5.5 ms, while the B and D versions, intended for set-top-box applications, feature a 130 ms 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 powers on and off without clicks or pops. The IC is available in a 3 mm x 3 mm x 0.8 mm, 16-pin TQFN and is specified over the extended -40°C to 85°C temperature range.