Preliminary

PUI Audio, Inc. A Projects Unlimited Company, 3541 Stop Eight Road, Dayton, OH 45414

Tel: (937) 415-5901 Fax: (937) 415-5925

Microphone

Operation

bit digital input pin mode, the user provides a signal that will put the microphone into Wake on Sound or

Normal modes of operation. When in the Wake on Sound mode, should a sound be detected, the

microphone will output a digital high through the dout pin. The user can then switch the microphone to

Normal mode by providing a digital low to the mode pin. The user would at some later point, provide a

digital high to the mode pin to return the microphone to Wake on Sound mode. Figure 2 shows the states

of various pins that are either user provided (mode, Vdd) or PMM-3738-VM1010-R provided (dout, Vout)

at three points of operation.

Figure 2: Timing diagrams showing turn-on time (left), transition time

into Wake on Sound mode (center) & Normal mode (right)

It is recommend topowerup the microphone in Normal mode (mode pin low), and then enter into

WoS mode as needed.

Product Revision Technical Update

The PMM-3738-VM1010-R has been updated with a wider Wake on Sound range, on parts date

code 1811 and higher, giving designers more configurability in the acoustic threshold and

allowing for ZeroPower Listening to be used in more applications. Previously, this range was from

65 to 78 dB SPL. On parts date code 1811 and higher, this range has been extended from 65 dB to

89 dB SPL.

To accommodate this change, users simply need to change the Rg (GA1 to GA21 external resistor)

value. See the table below for the value of Rg to use to configure the turn-on threshold.