Basic current mirror Small signal: Rin = 1/(gm1+gds1)  1/gm1 Chapter 3 Figure 01 Small signal: Rin = 1/(gm1+gds1)  1/gm1 Ai  gm2/gm1  W2/W1

Large signal: Iin = m1Cox1(W1/L1)(VGS1-Vt1)^2*(1+l1Vds1) = mCox(W1/L)(Vin-Vt)^2*(1+lVin) Iout = m2Cox2(W2/L2)(VGS2-Vt2)^2*(1+l2Vds2) = mCox(W2/L)(Vin-Vt)^2*(1+lVout) Iout/Iin = (W2/W1) *(1+lVout)/(1+lVin) So: need Vout=Vin to have accurate mirror ratio. Also: need Vout > Veff for the analysis to be valid.  Voutmin = Veff

D1 connects to S2 VDD Large signal: Want all T’s in saturation From ID1=IQ, estimate VG1Q by ignoring l-effect For M1 in sat, Vds1 > Veff1 From ID2=IQ, estimate VGS2Q Need VG2Q > VGS2Q+Veff1 For M2 in sat, Vds2 > Veff2 So, need Vo> VG2Q-Vt2 IQ M2 M1 Cascode

Small signal Assume all T’s in saturation Draw small signal circuit Compute small signal parameters Rin Ro Ai Av …

connecting S1 to D2 Source follower, or common drain amplifier. Read book for analysis. Av is less than but close to 1. Ro is small, so can drive resistive load. Commonly used as buffer

D1 connects to S2 VDD Large signal: same as cascode Small signal: IQ Ro same as cascode Rin = rds1||rincg rincg: be careful Av: Ai: IQ M2 M1 Common Gate amp

M2 M1 Vbb Vin CL M4 M3 Vyy Vxx VDD VDD Vo<Vxx+|Vt3| flip up-down for source Rb M2 Vbb CL M1 Vin connecting D1 to S2 cascoding Vo> Vbb-Vt2 ro = rop||ron, Av=-gm1*ro

VDD VDD flip left-right to get this differential telescopic cascoded amplifier M7 M5 Vyy Vxx Vo<Vxx+|Vt3| M8 M6 vo- vo+ CL M3 M4 Vbb CL M1 M2 vin+ vin- Vs Vo> Vbb-Vt2 Tail current to change gnd to virtual gnd

Let vin+ = Vic + ½ vid, vin- = Vic - ½ vid The cross source: Vs = Vic – VGS1Q. Left half circuit same as two slides back, but with vin = ½ vid. So vo- = - gm1ro-(½ vid), where ro- = ro5,7||ro1,3. Similarly, vo+ = - gm1ro+(-½ vid), where ro+ = ro6,8||ro2,4. Hence: vod = gm1rovid Av = vod/vid = gm1ro where ro = ro- = ro+

ICMR M3 M4 Vbb What is Vicmax? VD1 = Vbb-Vt3-Veff3 For M1 in saturation, need VD1>VG1Q–Vt1 =Vic–Vt1. So, Vic<Vbb-Vt3-Veff3+Vt1 Vicmax=Vbb-Veff3 What is Vicmin? Vs>Veff9 for M9 in saturation. Vic>Veff9+Veff1+Vt1 Vicmin=Veff9+Veff1+Vt1 M1 M2 vin+ vin- Is M1 M2 vin+ vin- M9

VDD VDD Diode connection to turn diff out to single-ended output  M7 M5 M8 Vo<VG6+|Vt6| M6 vo Same ICMR. But Vo range is different. VG6=VDD-2Vtp-2Veff M3 M4 CL Vbb M1 M2 vin+ vin- Vo>Vbb-Vt2 Same Av, ro

VDD VDD Vo Vo Folded cascode

VDD Vin CL Vbb flip up-down for I sources VDD M1 Vin CL M2 Vbb connecting n-D to p-S

VDD VDD folded cascode amp Vbb Vin+ Vin- CL

D1 connects to G2, two stages VDD VDD VDD VDD two stage CS amplifier CS amplifier with a source follower buffer

VDD VDD VDD V? Vx Vx Same as above, only T2 is pMOS Connecting S1 to D2 makes ro really small buffer or output stage