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Description
MAX9814 Electret Microphone Amplifier + pam8406 Amplifier with AGC Function Bone Conduction Speaker driver board
introduction
Using max9814 microphone amplifier + pam8406 amplifier design, high sensitivity, suitable for 3.6v-4.2v lithium battery-powered bone conduction speaker or bone conduction headphone driver for hearing aids to use. Potentiometer with power switch, easy to control.
Note
As the overall sensitivity of the board is relatively high, only applies to the bone conduction speaker drive, do other uses to see if it is appropriate. Audio output is not common, the two negative can not be linked together.
AGC switch
Plug in the supporting short-circuit cap AGC function off, no plug short-circuited hat AGC open.
Board size
50mm * 20mm
Operating voltage
DC 3v-5.5v
Board wiring pitch
2.54mm
Please refer to the release ratio and gain settings as follows: The three-state start-up and release ratio selection controls the start-up time and release time ratio of the AGC circuit: A/R=GND: Start/release ratio is 1:500 A/R=VDD: Start/release ratio is 1:2000 A/R=floating: The start/release ratio is 1:4000
tristate amplifier gain control:
GAIN = VDD, the gain is set to 40dB.GAIN = GND, and the gain is set to 50dB. GAIN = floating, the uncompressed gain is set to 60dB.
Remark: The --GAIN in the above figure is the gain end on the board. A/R is the release ratio. VDD=the number on the board is +1=the number on the board.
