Mixers RF IC for Wireless Communications Omar Wing Shanghai Jiao Tong University Omar Wing RF IC-Mixers 1 Shanghai Jiao Tong University
Omar Wing RF IC - Mixers Shanghai Jiao Tong University 1 Mixers RF IC for Wireless Communications Omar Wing Shanghai Jiao Tong University
Mixer Function To convert an RF signal at fer to an IF signal at fir by "mixing"the RF with a signal at fo generated by a local oscillator (LO). LO Image Rejection LNA Mixer IF amp Omar Wing RF IC-Mixers 2 Shanghai Jiao Tong University
Omar Wing RF IC - Mixers Shanghai Jiao Tong University 2 Mixer Function To convert an RF signal at to an IF signal at by "mixing" the RF with a signal at generated by a local oscillator (LO). RF IF LO f f f Image Rejection LNA Mixer IF amp LO RF f IF f LO f
Design Goals Mixing should generate only IF and no other frequency components. Conversion gain,IF/RF,should be high Conversion should be linear.Large IP3. Good dynamic range of RF. ·Low noise.Low power. Good isolation from strong LO. Omar Wing RF IC-Mixers 3 Shanghai Jiao Tong University
Omar Wing RF IC - Mixers Shanghai Jiao Tong University 3 Design Goals • Mixing should generate only IF and no other frequency components. • Conversion gain, IF/RF, should be high. • Conversion should be linear. Large IP3. • Good dynamic range of RF. • Low noise. Low power. • Good isolation from strong LO
Ideal Mixer ARE COSOREt -y(t) ALo cos@Lot y(t)=ARF COS ORFt.ALo cOS@Lot 2isrineos(@u0ol加+7Asr4oeoow+oolr Yr()=Ame Aro COs(@wr-0o) Conversion gain =ALo/2 Omar Wing RF IC-Mixers 4 Shanghai Jiao Tong University
Omar Wing RF IC - Mixers Shanghai Jiao Tong University 4 Ideal Mixer cos ARF RF t cos ALO LO t y(t) ( ) cos cos RF RF LO LO y t A t A t 1 1 cos( ) cos( ) 2 2 ARF ALO RF LO RF LO RF LO t A A t 1 ( ) cos( ) 2 IF RF LO RF LO y t A A t C o n ve rsio n g a in = / 2 AL O
Square Law Mixer y(t)=(ARF coS@RFt+ALo cos@Lot) -ARF ALo COS(ORF-@LO)t+ARF ALo COS(@RF +@Lo)t dc terms+terms at 20gr and 20Lo YIF (t)=ARr ALo COS(@RF-@LO)t Conversion gain =ALo Omar Wing RF IC-Mixers 5 Shanghai Jiao Tong University
Omar Wing RF IC - Mixers Shanghai Jiao Tong University 5 Square Law Mixer 2 ( ) ( cos cos ) RF RF LO LO y t A t A t cos( ) cos( ) ARF ALO RF LO RF LO RF LO t A A t dc terms + terms at 2 and 2 . RF LO ( ) cos( ) IF RF LO RF LO y t A A t Conversion gain =ALO