The MAX9867 is a codec specially designed for ultra-low power stereo applications. Its design is suitable for portable consumer devices such as mobile phones and portable gaming consoles. Stereo differential microphone inputs that can be connected to either analog or digital microphones is an added feature. It has single-ended line inputs, with configurable preamplifier, so input can be sent to the ADC for record or routed directly to the headphone amplifier for playback.
An auxiliary ADC path can be used to track any DC voltage. The stereo headphone amplifiers support differential, single-ended, and capacitorless output configurations. Using the capacitorless output configuration, the device can output 10mW into 32Ω headphones. Comprehensive click-and-pop circuitry suppresses audible clicks and pops during volume changes and startup or shutdown. Utilizing Maxim’s proprietary digital circuitry, the device can accept any available 10MHz to 60MHz system clock. This architecture eliminates the need for an external PLL and multiple crystal oscillators. The stereo ADC and DAC paths provide user-configurable voiceband or audioband digital filters. Voiceband filters provide extra attenuation at the GSM packet frequency and greater than 70dB stopband attenuation at fS/2. The MAX9867 operates from a single 1.8V supply, and supports a 1.65V to 3.6V logic level. An I2C 2-wire serial interface provides control for volume levels, signal mixing, and general operating modes. The MAX9867 is available in a tiny 2.2mm x 2.7mm, 0.4mm-ball-pitch, WLP package. A 32-pin 5mm x 5mm TQFN package is also available.
The stereo playback path accepts digital audio through a flexible interface compatible with I2S, TDM, and leftjustified signals. An oversampling sigma-delta DAC converts the incoming digital data stream to analog audio and outputs the audio through the stereo headphone amplifier. The headphone amplifier can be configured in differential, single-ended, and capacitorless output modes.
The stereo record path has two analog microphone inputs with selectable gain. An integrated microphone bias can be used to power the microphones. The left analog microphone inputs can also accept data from up to two digital microphones. An oversampling sigmadelta ADC converts the microphone signals and outputs the digital bit stream over the digital audio interface. Integrated digital filtering provides a range of notch and highpass filters for both the playback and record paths to limit undesirable low-frequency signals and GSM transmission noise.
_ 1.8V Single-Supply Operation
_ 6.7mW Playback Power Consumption
_ 90dB Stereo DAC, 8kHz ≤ fs ≤ 48kHz
_ 85dB Stereo ADC, 8kHz ≤ fs ≤ 48kHz
_ Battery-Measurement Auxiliary ADC
_ Support for Any Master Clock Between 10MHz to 60MHz
_ Stereo Digital Microphone Input Support
_ Stereo Analog Differential Microphone Inputs
_ Stereo Headphone Amplifiers: Differential, Single-Ended, or Capacitorless
_ Stereo Line Inputs
_ Voiceband Filter with a Stopband Attenuation Greater than 70dB
_ 1.65V to 3.6V Digital Interface Supply Voltage
_ I2S/TDM-Compatible Digital Audio Bus
_ 30-Bump, 2.2mm x 2.7mm 0.4mm-Pitch WLP
-Portable Gaming Devices
-Portable Navigation Devices
-Portable Multimedia Players
Repost: Oct 8th, 2009