MAX98089EVKIT+WLP Maxim Integrated, MAX98089EVKIT+WLP Datasheet - Page 60

• Manufacturer Part Number: MAX98089EVKIT+WLP
• Description: Audio IC Development Tools
• Manufacturer: Maxim Integrated
• Type: Audio CODECr

Specifications of MAX98089EVKIT+WLP

• Product: Evaluation Kits
• Tool Is For Evaluation Of: MAX98089
• Operating Supply Voltage: 2.8 V to 5.5 V
• Interface Type: I2C
• Operating Supply Current: 1 A

The MAX98089 is a fully integrated stereo audio codec
with FLEXSOUND technology and integrated amplifiers.
Two differential microphone amplifiers can accept signals
from three analog inputs. One input can be retasked to
support two digital microphones. Any combination of two
microphones (analog or digital) can be recorded simul-
taneously. The analog signals are amplified up to 50dB
and recorded by the stereo ADC. The digital record path
supports voice filtering with selectable preset highpass
filters and high stopband attenuation at f
ic gain control (AGC) circuit monitors the digitized signal
and automatically adjusts the analog microphone gain
to make best use of the ADC’s dynamic range. A noise
gate attenuates signals below the user-defined threshold
to minimize the noise output by the ADC.
The IC includes two analog line inputs. One of the line
inputs can be optionally retasked as a third analog micro-
phone input. Both line inputs support either stereo single-
ended input signals or mono differential signals. The line
inputs are preamplified and then routed to the ADC for
recording and/or to the output amplifiers for playback.
The single-ended line inputs signals from INA1 and INA2
can bypass the PGAs, and be connected directly to the
ADC input to provide the best dynamic range.
Integrated analog switches allow two differential micro-
phone signals to be routed out the third microphone input
to an external device. This eliminates the need for an
external analog switch in systems that have two devices
recording signals from the same microphone.
Through two digital audio interfaces, the device can
transmit one stereo audio signal and receive two stereo
audio signals in a wide range of formats including I
PCM, and up to four mono slots in TDM. Each interface
can be connected to either of two audio ports (S1 and
S2) for communication with external devices. Both audio
interfaces support 8kHz to 96kHz sample rates. Each
input signal is independently equalized using 5-band
parametric equalizers. A multiband automatic level con-
trol (ALC) boosts signals by up to 12dB. One signal path
additionally supports the same voiceband filtering as the
ADC path.
The IC includes a stereo Class D speaker amplifier, a
high-efficiency Class H stereo headphone amplifier, and
a differential receiver amplifier that can be configured as
a single-ended stereo line output.
Maxim Integrated
Detailed Description
S
/2. An automat-
Low-Power, Stereo Audio Codec
2
with FlexSound Technology
S,
When the receiver amplifier is disabled, analog switches
allow RECP/RXINP and RECN/RXINN to be reused for
signal routing. In systems where a single transducer is
used for both the loudspeaker and receiver, an exter-
nal receiver amplifier can be routed to the left speaker
through RECP/RXINP and RECN/RXINN, bypassing the
Class D amplifier. If the internal receiver amplifier is used,
then leave RECP/RXINP and RECN/RXINN unconnected.
In systems where an external amplifier drives both the
receiver and the MAX98089’s line input, one of the dif-
ferential signals can be disconnected from the receiver
when not needed by passing it through the analog switch
that connects RECP/RXINP to RECN/RXINN.
The stereo Class D amplifier provides efficient amplifica-
tion for two speakers. The amplifier includes active emis-
sions limiting to minimize the radiated emissions (EMI)
traditionally associated with Class D. In most systems,
no output filtering is required to meet standard EMI limits.
To optimize speaker sound quality, the IC includes an
excursion limiter, a distortion limiter, and a power limiter.
The excursion limiter is a dynamic highpass filter with
variable corner frequency that increases in response
to high signal levels. Low-frequency energy typically
causes more distortion than useful sound at high sig-
nal levels, so attenuating low frequencies allows the
speaker to play louder without distortion or damage. At
lower signal levels, the filter corner frequency reduces
to pass more low frequency energy when the speaker
can handle it. The distortion limiter reduces the volume
when the output signal exceeds a preset distortion level.
This ensures that regardless of input signal and battery
voltage, excessive distortion is never heard by the user.
The power limiter monitors the continuous power into the
loudspeaker and lowers the signal level if the speaker is
at risk of overheating.
The stereo Class H headphone amplifier uses a dual-
mode charge pump to maximize efficiency while out-
putting a ground-referenced signal. This eliminates the
need for DC-blocking capacitors or a midrail bias for the
headphone jack ground return. Ground sense reduces
output noise caused by ground return current.
The IC integrates jack detection allowing the detection
of insertion and removal of accessories as well as button
presses.
MAX98089
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