[SOLVED] dtmf decoder using 8870

[akshay15]

i m making project on dtmf decoder and i am unable to get output through my mt8870 ic .i have tried different gain by changiing resistor values between ppin 2 and pin3.but still no breakthrough in the circuit. please help me out.

 

[pranam77]

Trace your circuit again, and see xtal used is 3.59Mhz. Also there are ample duplicate makes of 8870 in the market. Confirm the chip is from a reliable source. Try other chip from different vendor too. You may also tri KT3170 as a pin to pin replacement.
Cheers

 

[akshay15]

yes i hav have placed a 3.59MHZ crystal oscillator .i m using a 9v cell to power it can this be a problem .what is the the maximum output current of this cell?.could this have damaged my mt8870 ic ??