Dearest Electronics Wizzards,
I'm trying to amplify the sound coming out of a Sparkfun MP3 Trigger board.
For this, I was planning to use the Analog Devices SSM2305 Amplifier.
However, the MP3 Trigger product page is filled with posts mentioning
the need for "ESD Protection" if you ever connect the board to anything
else then headphones. Furthermore, the data sheet for the SSM2305 mentions
"input coupling capacitors", but only under certain conditions. I could use some
advice as to which of these components I do need in my specific situation. I'm
planning to implement everything on one circuit board, running of a 5V battery.
Thanks in advance,
Jim
A bit of a semi-stealth bump update.
The SSM2305 Datasheet > http://www.analog.com/static/imported-files/data_sheets/SSM2305.pdf
The current layout I have > http://www.jimboproductions.be/server/projects/war_crosses/WarCrosses_Hardware_V1.jpg
The MP3 Trigger webpage > MP3 Trigger - WIG-13720 - SparkFun Electronics
Hey Mods, maybe this thread should be moved?
I'm really hoping I could get some info on this problem, but maybe
it will have more success in the "general electronics" section?
Hi BB, I did not read the data sheets you gave, but it is safe to add ESD protection and a series capacitor. The audio output voltage should be measured by you. It is good to use a voltage divider to keep the amplitude at about .1 volts peak voltage. If you measure a DC offset in the signal, the series capacitor will block that. I did this on my circuit as follows:
My output voltages were 3v plus or minus 3v. So I has a 6 v peak voltage and 0 v min. To get .1 volt audio voltage, I used a voltage divider of 2 resistors to get 1/60th of the voltage. Then a 1 uF polyester film capacitor in series followed by a 1 meg R to ground.
The ESD can be two diodes to the rails. ESD is 3000 volts, so is is OK to use diodes that conduct current only if the voltage is 0.7v over vcc or 0.7v under ground. A 470 ohm series R can be in series with the ESD diodes.
Thanks for the answer, Ambilobe.
I could use it even more "dumbed down", though.
Do I absolutely NEED any of these input coupling capacitors
or ESD protection components in my specific layout?
I would rather not implement them if not needed.
Thanks in advance,
Jim
"Do I absolutely NEED any of these input coupling capacitors
or ESD protection components in my specific layout? "
No.
Hah - excelent. I'll let you know if I manage to make magic smoke! 
If not needed, then why are they there? Will they make the circuit more robust?