Analog Integrated Circuit Design

2nd edition


Problem 4.25

1. Schematic

1-1. With the source-follower

1-2. Without the source-follower

2. HSPICE Netlist

2-1. With the source-follower

* Problem 4.25

 

* MOS model

.include p35_cmos_models_tt.inc

 

* main circuit

mn1 1 2 3 3 nmos L=0.35u W=100u

Cin 2 0 30f

Rin 2 0 5K

CL 3 0 8p

 

* current source

Ibias 3 0 1.5m

Iin 0 2 dc 200u ac 1

** Iin dc value adjusted to ensure mn1 is in active region

 

* voltage source

vdd 1 0 dc 3.3

 

* analysis

.op

.ac dec 10 1k 100G

 

* options

.options post

.end

2-2. Without the source-follower

* Problem 4.25 without the sourece-follower

* MOS model
.include p35_cmos_models_tt.inc

* main circuit
Cin 2 0 30f
Rin 2 0 5K
CL 2 0 8p

* current source
Iin 0 2 dc 200u ac 1
** Iin dc value adjusted to ensure mn1 is in active region

* analysis
.op
.ac dec 10 1k 100G

* options
.options post

.end

3. Simulation Result

 

fT [MHz]
with the source follower 228
without the source follower 3.98



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