Maxim Integrated introduced two series of 92 percent efficient tiny audio amplifiers. The MAX98357 is a digital pulse-code modulation (PCM) power amplifier, and the MAX98358 is a digital pulse-density modulated (PDM) power amplifier. Both are input Class D amplifiers that provide Class AB audio performance, offering five selectable gains (3 dB, 6 dB, 9 dB, 12 dB and 15 dB).
Two types of the MAX98357 supporting 8-channel time division multiplexed (TDM) data are offered: the MAX98357A supporting I2S data and the MAX98357B supporting left-justified data.
The MAX98358 can take a stereo pulse density modulated (SPDM) input directly into the digital to analog (DAC) converter.
Both device’s packages are available in 9-in wafer-level packaging (WLP), (1.345 mm x 1.435 mm x 0.64 mm) and 16-pin TQFN (3 mm x 3 mm x 0.75 mm) packages. Both are also specified for a temperature range of minus 40 degrees Celsius to 85 degrees Celsius.
These amplifiers are designed for applications ranging from cellular phones and tablets to notebooks and netbooks.
Important specifications and features include:
- Single-supply operation (2.5 V to 5.5 V)
- 3.2W output power into 4Ω at 5 V
- 1.8 mA and 2.4 mA quiescent current
- 92 percent efficiency (RL = 8Ω, POUT = 1 W)
- 25µVRMS output noise (AV = 15dB)
- Low 0.015 percent THD+N at 1kHz
- Sample rates of 8 kHz to 96 kHz
- Sophisticated edge rate control enables filterless Class D outputs
- 77dB PSRR at 217 Hz and 1 kHz
- Low RF susceptibility rejects TDMA noise from GSM radios
- Extensive click-and-pop reduction circuitry
- Robust short-circuit and thermal protection
- Available in space-saving packages: 1.345 mm x 1.435 mm WLP (0.4 mm pitch) and 3 mm x 3 mm TQFN
