Simplified Block Diagram
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- Low Emissions, Filterless Class D Amplifier Achieves Better than 10dB Margin Under EN55022 Class B Limits
- Low RF Susceptibility Design Rejects TDMA Noise from GSM Radios
- Input Mixer with User-Defined Input Mode
- 725mW Speaker Output (RSPK = 8Ω, PVDD = 3.7V)
- 53mW Headphone Output (RHP = 16Ω, VDD = 3.7V)
- Low 0.05% THD+N at 1kHz (Class D Power Amplifier)
- Low 0.016% THD+N at 1kHz (Headphone Amplifier)
- 87% Efficiency (RSPK = 8Ω, POUT = 750mW)
- 1.6Ω Analog Switch for Speaker Amplifier Bypass
- High Speaker Amplifier PSRR (72dB at 217Hz)
- High Headphone Amplifier PSRR (84dB at 217Hz)
- I²C Control
- Hardware and Software Shutdown Mode
- Click-and-Pop Suppression
- Current-Limit and Thermal Protection
- Available in a Space-Saving, 2.5mm x 2.0mm MaxFilm Package
- Cell Phones
- Portable Multimedia Players
The MAX9877A delivers up to 725mW from a 3.7V supply into an 8Ω load with 87% efficiency to extend battery life. The filterless modulation scheme combined with active emissions limiting circuitry and spread-spectrum modulation greatly reduces EMI while eliminating the need for output filtering used in traditional Class D devices.
The stereo Class AB headphone amplifier in the MAX9877A uses Maxim's DirectDrive architecture, that produces a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors, saving cost, space, and component height.
The device utilizes a user-defined input architecture, three preamplifier gain settings, an input mixer, volume control, comprehensive click-and-pop suppression, and I²C control. A bypass mode feature disables the integrated Class D amplifier and utilizes an internal DPST switch to allow an external amplifier to drive the speaker that is connected at the outputs of the MAX9877A.
The MAX9877A is available in a thermally efficient, space-saving 20-bump MaxFilm package.