All Problems in Single file : [PDF] [Solutions]
a. calculate the value of the small signal output resistance of the Wilson current
15. The basic idea used in the regulated cascode current sink is shown below.
16. Consider the schematic of the modified current
mirror shown below. Estimate the small signal resistance to ground at both
nodes A and B. if a resistor is used to connect node A to VDD, write
an equation relating the drain currents of M1 and M2 to the resistor value.
- Design a simple current mirror using a current of 1 μA and VGS of 1 volt.
- Design a circuit to bias the MOSFET in figure
shown, so that its drain current is 5 μA. Estimate the minimum voltage across
M1 if it is to remain in saturation.
- Determine the current that flows in M3 of figure shown. Neglect oxide encroachment and
the finite output resistance of the M3.
- Determine the currents that flow in figure
shown, if the size of M2 is 30/5. Compare the results with above problem and
write your observations.
- Determine the ac currents that comes from source vt. Assume λ = 0.06 per
volt.
- Design a bias circuit so that the current that
flows in M1 and M2 is 1μA. What are the small signal resistances looking into
the drains of M2 and M1 ? what is the minimum voltage across M1 and M2 for
operation in the saturation region ?
- Using small signal analysis, prove that the
resistance looking into drain of figure shown is
- For the circuit shown below, design current
sources with output currents of 10 μA and 15 μA. Estimate the minimum voltage
across the current sources and the output resistance. What is the VSG
of the 100/5 MOSFET that sources 10 μA current ?
- Estimate the variation in Io for the
simple current mirror shown below, for VSS changing from -2.4 volts
to -2.6 volts.
- Assume that a threshold voltage difference of 10 mV exists between the two MOSFETs used in a simple current mirror made using equal size MOSFETs. Calculate the difference in the drain currents to change with the MOSFET VGS ? Is matching between the currents better or worse with large VGS ? what happens to the minimum voltage across the current mirror if VGS is increased ?
- Using the Wilson
current mirror shown in figure and the CN 20 process, design a mirror in which
Io = 150 μA with I REF = 50 μA for VDD = 5
volts, VSS = 0 volts.
- A Wilson current mirror
is designed with VDD = 5 volts, VSS = 0 volts, IREF
= 10 μA and all devices sized to 10 μm / 10 μm. a.
calculate the value of the small signal output resistance of the Wilson current
mirror. b.
calculate the minimum output voltage, Vomin. c.
Layout the devices M4 through M7, assuming that each device is 40/5 using
an interditigated layout technique to match devices M5 and M6. Use
parallel devices for M4 and M7.
a. calculate the value of the small signal output resistance of the Wilson current
mirror.
b. calculate the minimum output voltage, Vomin.
14. Design
a regulated cascode current sink of 1 μA. Estimate the output resistance
of the current sink.b. calculate the minimum output voltage, Vomin.
15. The basic idea used in the regulated cascode current sink is shown below.
What is the output resistance of this configuration?
show that if the gain A is gm(ro/2), then the output resistance of the
configuration reduces to
