Abstract

The LMX2820 RF synthesizer has a hardware MUTE pin to mute or unmute the RF outputs instantaneously. The attenuation after mute is as high as 50 dB. If the application system requires to switch or to sweep frequency very quick, the user can use two LMX2820 and a RF switch to ping-pong the two LMX2820's output. The additional isolation from the RF switch can probably add up the total attenuation on the mute side to more than 80 dB. This ping-pong architecture approach is therefore an excellent choice for high-power output system.

LMX2820 has Instant Calibration feature that allows VCO frequency change in a very short period of time. During the mute period, the user can change the VCO frequency so that a new frequency can pop up in the next unmute period. As a result, the user can sweep the output frequency of this ping-pong system very fast.