Wamicon 2005 1GHz Clearwater Florida

1. M. Zamin Khan & R. Raut
SSUET, Pakistan &
Concordia University, Canada
Presented by M. Zamin Khan

2. Agenda
 Introduction and Motivation
 Noise Figure and Optimization
 Low Noise Amplifier Topologies
 Proposed Design Approach
 Simulation Results
 Conclusion

3. Introduction
LNA is a key component in RF-Front-End
receiver
 Enough gain
 Over all noise figure
 Linearity
 Low power consumption
RF Filter LNA
Image-reject
Filter
L0

4. Motivation
 The apparent simplicity of an LNA
is misleading.
 Design should be easy because of
relatively few Components.
 Trade-Offs complicate the design.
 Proposed topology is suitable to
design LNA for 0.65V power
supply

5. Noise Figure represents how much the
given system degrades the signal-to-noise
ratio, which is defined as
Noise Figure and Optimization-I

6. Noise Figure and Optimization-II
• A LNA determines the performance of the
communication system.
• A system noise factor is defined as
N o is e
S t a g e 1
N o is e S t a g e 2 N o is e S t a g e M
A 1 , F 1 A 2 , F 2 A M , F M
R L V O U T
R S
m a t c h e d
m a t c h e d
V I N
Ftot = F1 + (F2 – 1) / A1
2
+ (F3-1)/(A1
2
A2
2
) + … + (FM-1)/(A1
2
…AM-1
2
)

7.  Sensitivity in the system
 Determine the over all NF
 Add as little Noise as possible
 Provide enough Gain
Noise Figure and Optimization-III

8. LNA Topologies-I
---- Classical noise matching
• Simply to provide 50
ohm impedance
matching at the input
port
• Large noise penalty
• One cannot obtain
input matching and
minimum N.F
simultaneously

9. LNA Topologies-II
---- Inductively degenerated common-
source amplifier
To achieve lower noise and input matching, input impedance of
the LNA is
Disadvantages:
• Cascode topology needs
higher power supply
• Consumes more power

10. Proposed design approach
• The proposed topology
works for low power
supply such as 0.65V
• Input matching without
increasing any N.F
• Casecode common
source common gate
topology gives higher
Gain

11. Complete Schematic of
proposed LNA Design

12. Simulation Results-I
Power Gain=23dB N.F=1.1dB

13. Simulation Results-II
S11=-13.5dB S22=-21dB

14. Simulation Results-III
IIP3=-29dBm

15. Layout of the Proposed LNA

16. Comparison of various recent
reported LNAs

17. Conclusion
 Spectre simulation TSMC 0.18um CMOS
technology
 Low power supply=0.7V
 Low N.F=1.1dB
 High power gain=23dB
 S11=-13.5dB(Good input matching)
 S22=-21dB(Good output matching)
 S12=-72dB
 Very low power consumption=8.4mw

18. Thank You!