1528 半导体学报 第26卷 V PMO UP+ UPH+ Level UP- shifter UPH+ UPH- DNH- DNH+ UPH- (L2H) PM2 PMI DN+ DNH+ Level PM4 PM3 DN- shifter DNH- (L2H) UP+ UPL+ Level UPL- NM4 NM UP- shifter (L2L) DN+ DNL+ DNL DNL+ Level NM2 NMI DN- shifter DNL- (L2L) MO Fig.3 Differential charge pump schematic changest.The obvious improvement here is that extra variation is considered,contributed from not THDADECIEINCIINCI only N but also the charge pump current Ice,loop filter,and VCO gain Kvco. 3.3 Linear gain VCO Fig.4 Proposed current cell with double-half adjust- VCO comprises complementary cross-coupled ment negative Gm pairs and LC-tank,as shown in Fig.5. Vep and Vem are differential control nodes to in- which two are ON and two are OFF in default.If a crease the linearity of Kvco by symmetry.The tank is larger than amax,it should decrease the current Ier by disable (nDEC=0)one current branch to consists of inductor,capacitor,and cross-switched varactors.The varactors are realized by MIM ca- half the factor a.If a is smaller than amin,then in- crease Icp by enable (INC=1)two current bran- pacitors and the cross switches are realized by tran- ches to double the factor.For example,if amin sistors.Excellent linear property has been demon- 0.5,amax=1.5,△Kvco/Kvco=0.2,△Ie/I.=0.2, strated in Ref.[13].The better linear VCO gain △R/R=0.2,and△C/C1=0.l,the worst total results in smaller variation and is better for the negative variation without adjustment according to stability.Phase noise performance can also be im- Eq.(15)is 0.37,which is below amin and the loop proved with inductors L1,L2 and capacitors Cl~ tends to be under-damping.With the current doub- C3. le adjustment,the total variation factor becomes 3.4 Divider 0.74,which is acceptable.The similar half adjust- ment is for the worst positive variation.The simple A divider is implemented in ripple-like local- current cell can replace the transistor NMO and feedback architecture.The divider has a range PMO in Fig.3.There is also a complex technique from 24 to 2"+1-1.The most important benefit of that adjusts current to keep the ratio Ice/N as N the structure is to reuse the 2/3 divider cell.The半 导 体 学 报 第!#卷 U8J>4 18HH=D=?F879:G7DJ=MN6M<:G=67F8: U8J>2 -DEME<=R:NDD=?F:=99@8FGRENK9=0G79H7R;N<F0 6=?F @G8:GF@E7D=W+7?RF@E7D=WUU8?R=H7N9F>(H) 8<97DJ=DFG7?)67\$8F<GEN9RR=:D=7<=FG=:NDD=?F T)- KLR8<7K9= %?1’)g"&E?=:NDD=?FKD7?:GFE G79HFG=H7:FED)>(H)8<<6799=DFG7?)68?$FG=?8?0 :D=7<=T)- KL=?7K9= %(+)g$&F@E:NDD=?FKD7?0 :G=<FERENK9=FG=H7:FED>UED=\76M9=$8H)68? g "‘5$)67\ g$‘5$,NV)W)NV)W g"‘!$,T:)T: g"‘!$ ,B)Bg"‘!$7?R ,A$)A$ g"‘$$FG= @ED<FFEF79 ?=J7F8X=X7D87F8E?@8FGENF7R;N<F6=?F7::EDR8?JFE ’^>%$5&8<"‘43$@G8:G8<K=9E@)68?$7?RFG=9EEM F=?R<FEK=N?R=D0R76M8?J>S8FGFG=:NDD=?FRENK0 9=7R;N<F6=?F$FG=FEF79X7D87F8E?H7:FEDK=:E6=< "‘32$@G8:G8<7::=MF7K9=>/G=<86897DG79H7R;N<F0 6=?F8<HEDFG=@ED<FME<8F8X=X7D87F8E?>/G=<86M9= :NDD=?F:=99:7?D=M97:=FG=FD7?<8<FED +A"7?R -A"8?U8J>4>/G=D=8<79<E7:E6M9=\F=:G?8^N= FG7F7R;N<F<:NDD=?FFEa==MFG=D7F8ET)-)G 7<G :G7?J=<-3. >/G=EKX8EN<86MDEX=6=?FG=D=8<FG7F =\FD7X7D87F8E?8<:E?<8R=D=R$:E?FD8KNF=RHDE6 ?EF E?9LG KNF79<EFG=:G7DJ=MN6M:NDD=?FT)-$9EEM H89F=D$7?RV)WJ78?NV)W> TYT 5JG@CA=CJG80% V)W:E6MD8<=<:E6M9=6=?F7DL:DE<<0:ENM9=R ?=J7F8X=?6 M78D<7?RP)0F7?a$7<<GE@?8?U8J>5> U:M 7?RU:? 7D=R8HH=D=?F879:E?FDE9?ER=<FE8?0 :D=7<=FG=98?=7D8FLEHNV)W KL<L66=FDL>/G=F7?a :E?<8<F<EH8?RN:FED$:7M7:8FED$7?R:DE<<0<@8F:G=R X7D7:FED<>/G=X7D7:FED<7D=D=798]=RKL A(A :70 M7:8FED<7?RFG=:DE<<<@8F:G=<7D=D=798]=RKLFD7?0 <8<FED<>’\:=99=?F98?=7DMDEM=DFLG7<K==?R=6E?0 <FD7F=R8? Z=H>-$4.>/G=K=FF=D98?=7DV)W J78? D=<N9F<8?<6799=DX7D87F8E?7?R8<K=FF=DHEDFG= <F7K898FL>-G7<=?E8<=M=DHED67?:=:7?79<EK=860 MDEX=R@8FG8?RN:FED<P$$P!7?R:7M7:8FED<)$# )4> TYU $JXJL@A * R8X8R=D8<86M9=6=?F=R8?D8MM9=098a=9E:790 H==RK7:a7D:G8F=:FND=-$2. >/G=R8X8R=DG7<7D7?J= HDE6 !L FE!(f$ 0$>/G= 6E<F86MEDF7?FK=?=H8FEH FG=<FDN:FND=8<FED=N<=FG=!)4R8X8R=D:=99>/G= $5!&