Synthesizer Block Diagram 8 Digital AFC Band Shift Level Shift cpo re Voltage /co PFD div Monitor C: /CO R Level cno S2 Shift Differential LPF cn Differential CP Divider DSM 6
6 Synthesizer Block Diagram Differential LPF PFD Digital AFC fref R1 R1 C1/2 C2 C2 R3 R3 C 3 C 3 Vref s1 s1 s 2 s 2 Differential CP up upb dn dnb Level Shift Vref s1 s1 Vcp Vcn Vcpo Vcno Divider DSM N fvco 8 Band Shift VCO LDO fdiv Voltage Monitor Level Shift
Simplified differential LC-tank Differential tuning of VCO -Inversion MOS transistors as varactors n-type /-MOS varactors p-type /-MOS varactors fixed capacitors 7
7 Simplified differential LC-tank • Differential tuning of VCO – Inversion MOS transistors as varactors Vop L Von Vcn Vcp n-type I-MOS varactors p-type I-MOS varactors fixed capacitors
Conventional Differentially Tuned Techniques Vocm=(Vop+Von)/2 p Vthn Vecm=(Vep+Ven)/2 ocm Vocm=(Vop+Von )2 好 op Vocm 8
8 Conventional Differentially Tuned Techniques Vccm=( Vcp + Vcn)/2 Vthn Vthn Vop Von Vcn Vcn Cn Vocm Vthn |Vthp| Vop Von Vcp Vcp Cp |Vthp| Vocm |Vthp| Vocm=( Vop + Von)/2 Vocm=( Vop + Von )/2