chaturvedi_san
Newbie
lmx2326
Hi I need help. I am designing a PLL at 1680 MHz using LMX2326 with a cutom VCO (1650-1700 MHz with atuning range of 0 to +5volts). I use a third order passive Loop filter designed on natinal webbench(C1:47pF, R2:68KΩ,C2:330pF,R3:82KΩ,C3:39pF). The reference oscilator is generating a peak to peak signal of ~3.8-4.2Volts. Still the PLL doesnot lock. The o/p of the loop filter always stays at 0V. I have tried both programming the LMX2326 with a ATtiny microcontroller as well as National's codeloader software but with same result (no lock!!). Please guide
Hi I need help. I am designing a PLL at 1680 MHz using LMX2326 with a cutom VCO (1650-1700 MHz with atuning range of 0 to +5volts). I use a third order passive Loop filter designed on natinal webbench(C1:47pF, R2:68KΩ,C2:330pF,R3:82KΩ,C3:39pF). The reference oscilator is generating a peak to peak signal of ~3.8-4.2Volts. Still the PLL doesnot lock. The o/p of the loop filter always stays at 0V. I have tried both programming the LMX2326 with a ATtiny microcontroller as well as National's codeloader software but with same result (no lock!!). Please guide