Which IC produces PWM that can be filtered into sine wave?
If you begin with an analogue sine wave (basically an oscillator like a Colpitts or phase shift type), you can adjust it's amplitude to 1 volt peak to peak and feed it into an LTC6992.


  
  Pulse Width Modulation (PWM) Controlled by Simple 0V to 1V Analog Input 
  
  
  The LTC®6992 is a silicon oscillator with an easy-to-use analog
  voltage-controlled pulse width modulation (PWM) capability.




\$R_{SET}\$ adjusts the oscillation frequency of the PWM.