1. 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

2. 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

3. 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

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

5. 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

6. 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

7. 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

8. 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

9. 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+

10. 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

11. 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

12. VDD
VDD Vo Vo
Folded cascode

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

14. VDD
VDD
folded cascode amp
Vbb
Vin+
Vin- CL

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

16. 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