const byte LED = 3; // Timer 2 "B" output: OC2B
const int divider = 2;
const long frequency = 150000L; // Hz (eg:150000=150khz)

void setup()
{
  Serial.begin(9600);
  pinMode (LED, OUTPUT);

  TCCR2A = _BV (WGM20) | _BV (WGM21) | _BV (COM2B1); // fast PWM, clear OC2B on compare
  TCCR2B = _BV (WGM22) | _BV (CS21); // fast PWM, prescaler of 8
  OCR2A = ((F_CPU / 8) / frequency) - 1; // zero relative
  OCR2B = ((OCR2A + 1) / divider) - 1; // 50% duty cycle
}

void loop()
{
}