Mackenzie Cook
Mohamed Khelifi
Jonathon Lee
Meshegna Shumye
Supervisors: John W.M. Rogers, Calvin Plett
1


Motivation and Applications
Block Diagram
2
3
LNA
Meshegna Shumye
LNA Schematic





Requirements:
Good Gain
Low Noise
Good Linearity
Input Matching
Gain vs. Frequency
Noise Figure vs. Frequency
4.3
21.0
4.2
20.0
NF (dB)
Gain (dB)
20.5
19.5
19.0
18.5
4.1
4.0
3.9
18.0
3.8
17.5
3.7
17.0
1
10
100
Frequency (MHz)
Gain
=
18dB
1000
1
10
100
Frequency (MHz)
NF = 3.8 dB
1000
Pout (dBm)
1dB Compression
Pin vs. Pout
-30
-20
-35
-30
-40
Pout (dBm)
-40
-45
-50
-55
-50
-60
-70
-60
-100
-90
-80
-70
-65
-80
-70
-90
-60
Pin (dBm)
P1dB = -68dBm
-50
-40
-90
-80
-70
-60
-50
Pin (dBm)
IIP3 = -52 dBm
-40
220u
220u
Mackenzie Cook
9

Traditional Superheterodyne Architecture
◦ High Order Filtering
◦ Off Chip Requirements

Quadrature Feedback Channel Selection at RF
◦ First Order Filtering
◦ Significantly Reduced Off Chip Requirements
10

20dB Stop Band Rejection

5dB Adjacent Channel Rejection
 200kHz channel spacing at 88-108MHz

150kHz bandwidth

Tunable Channel Selection via Local Oscillator

Differential Operation
11
Interference
Amplified
Desired Channel
Removed
Desired Channel
Mixed to 0Hz
12
13
14
100MHz Passed
Adjacent Channel
11.3dB Rejection
Peak Rejection 18.6dB
15
1.8mm
2.2mm
16
Mohamed Khelifi
17
Local Oscillator: The Story
HF
HF
Channel
Select
Filter
LF
FM
Demodulator
Reference
Signal
Channel Select Voltage
Control
Generator
Oscillators

Context: a local reference is fundamental to RF design.

Why: Reference frequencies for signal manipulations

Solution: a set of electrically tunable oscillators
18
Local Oscillator: The Solution
Ring Oscillator
4
3
Voltage (V)
460 MHz
Sinewave
2
1
0
2.0E-08
4.0E-08
6.0E-08
8.0E-08
Time

Delay In Each Stage + Negative Feedback = Oscillation

Minimum stages = 3

Highest Frequency so Far
◦ 460 MHz before tuning
◦ Tunable down to 380 MHz (voltage controlled C’s).
19
Local Oscillator: The Optimization
Voltage (V)
6
Voltage Vs Time
4
2
115 MHz
Squarewave
0

Frequency divide-by-2 FlipFlops

Advantages

Disadvantage – Size increase due to dividers
◦ Squarewave - easier to work with
◦ Four Phases for the Channel Select
◦ Frequency error also divided down
20
Local Oscillator: The Challenges

IC Area

Overall Integration – Cannot use resonator (C and L)

Varying LO Demand from µFM components
21
Jonathon Lee
22
FM Demodulation
-How to extract the information
• A phase locked loop (PLL) can be used for FM demodulation
FM Signal
Charge Pump
VDD
Demodulated Signal
PFD
Phase
Frequency
Detector
UP
id
PLL
DN
Loop Filter
R
C1
C2
Voltage Controlled
Oscillator
VCO
PLL
• In Summary: The PLL, through feedback, tracks the frequency
of the FM signal. The control voltage of the VCO is the
demodulated signal.
23
Circuit Layout
Phase Frequency Detector (PFD)
Charge Pump
Loop Filter (Off chip)
VCO
24
PLL – Acquisition and Lock
Voltage (V)
fc = 12.5 MHz
•
•
•
•
Time (µs)
Blue Waveform (Input): 50 kHz pure sine wave
Red Waveform (Output): The output of the demodulator
The first 95 µs are the start-up transient as the PLL acquires lock
Lock range (11.88 MHz – 14.38 MHz)
25

Design – No PMOS transistors (NMOS only)

Simulation – Initially no models for 2.5 µm
NFETs

Layout - Single metal layer
26

Completed design and fabrication of 7 RF
circuits

Generated and updated transistor models for
Carleton’s Process

First group ever to design 2.5 µm circuits
using Carleton’s Process
27
Team: Remaining Work
Testing the silicon
RF Probes
28

Two possible paths:
1. Create a product:
 Connect all ICs on chip
 Select:
 Power supply
 Antenna
 Audio amplifier
 Product packaging
2. Further Research:
 Further integration of off-chip components
 Optimization (layout and circuitry)
 Higher frequency applications
29
Thank you for your attention.
Questions?



John Rogers and Calvin Plett
Garry Tarr and Ryan Griffin
Rob Vandusen and Angela Burns
30
Local Oscillator
Ring OSC
Freq. ÷2
•
Context: Low frequency => cheaper ; high
frequency => better RF performance, smaller size.
•
Need: local reference signals for RF signal
manipulations (e.g. RF  low frequency).
•
Delivered: an electrically (voltage) tunable
oscillator operating at required frequencies.
•
Optimization: 4-Phase high frequency Squarewave
– Better compatibility for PLLs and Channel Select.
– Dividers divide down differences errors make.
31
Frequency Modulation (FM)
Frequency ≈ 10 𝑘𝐻𝑧
Frequency ≈ 100 𝑀𝐻𝑧
Transmit (Tx)
Voice Amplitude
Time
FM Modulator
(VCO)
Antenna
In Summary: Amplitude variations of the desired signal are transmitted
as frequency variations of the carrier frequency
Receive (Rx)
Voice Amplitude
Antenna
FM Demodulator
(PLL)
Time
In Summary: Frequency variations of the carrier frequency are converted to
variations in the amplitude of the received signal
32
2.
Designing an NMOS charge pump
CMOS
CP
UP
DN
UP
DN
33
Commercial FM Spectrum (Radio)
Commercial FM broadcasting:
• 101 FM channels located between 87.9 MHz and 107.9 MHz
• 200 kHz channel spacing
Channel Spectrum:
• Mono audio between 30 Hz – 15 kHz
• Stereo audio between 23 kHz - 53 kHz
• Additional spectrum for services above 53 kHz
34
Layout - Metal Routing
35
Step-by-Step Demod Example
1.
Initial Conditions:
–
–
Incoming FM frequency is 10.75 MHz
Loop VCO frequency is 10.70 MHz
• Therefore the VCO frequency must increase to match incoming
frequency
2. Transient Action:
–
The PFD sees the mismatch in frequencies and tells the VCO
frequency to speed up:
I.
II.
III.
PFD tells the charge pump to pump more current into the loop
This increase in current is converted to an increase in voltage by the loop filter
This increase in voltage is at the input of the VCO
–
The loop frequency will increase since the output frequency of the VCO is proportional
to the input voltage
3. Lock Obtained:
–
The VCO frequency will now stay locked with the incoming
frequency until it changes again!
36
PLL Design Considerations
• Frequency Response
– Natural Frequency (ωn)
• Determines bandwidth of the PLL
𝜔𝑛 =
𝐾𝑝ℎ𝑎𝑠𝑒 𝐾𝑉𝐶𝑂
𝐶1
– Damping Coefficient (ζ)
• Designed to be 0.707 (critically damped)
𝜁=
𝑅
𝐾𝑝ℎ𝑎𝑠𝑒 𝐾𝑉𝐶𝑂 𝐶1
2
37
PLL Waveforms
Input
Loop
Charge
Pump
Reset
38
PLL Response to 3 MHZ Frequency Step
39