Download The Design of a Radiation Tolerant, Low Power, High Speed Phase

The Design of a Low-Power
High-Speed Phase Locked Loop
Tiankuan Liu1, Datao Gong1, Suen Hou2, Zhihua Liang1, Chonghan Liu1,
Da-Shung Su2, Ping-Kun Teng2, Annie C. Xiang1, Jingbo Ye1
1
Department of Physics, Southern Methodist University, Dallas TX 75275,
U.S.A.
2 Institute of Physics, Academia Sinica, Nangang 11529, Taipei, Taiwan
[email protected]
Outline
• Introduction
• PLL Design
–
–
–
–
Block diagram
Layout
VCO design and simulation
Divider design and simulation
• PLL performances
– Acquisition time
– Deterministic jitter
– Random jitter
• Conclusion
• Acknowledgments
2
Introduction
• Application background
ATLAS Liquid Argon Calorimeter Optical Link Upgrade
Present
Upgrade
Data rate per front-end board (FEB) (Gbps)
1.6
100
Power consumption per Gbps (mW)
1188
90
• Silicon-on-Sapphire (SoS) CMOS technology
– High speed, low power, high quality inductors, no latch-up
– The radiation tolerance of a commercial 0.25 µm SoS CMOS technology has
been evaluated in the previous study
• Design Goals:
– Operation frequency: 4 ~ 5 GHz for data rate 8 ~ 10 Gbps
– Random jitter < 1 ps (RMS)
– Power consumption < 100 mW
3
PLL Design: Block Diagram
Phase
frequency
detector
Test
points
LC-tank based voltage
controlled oscillator
(VCO)
Divider (divide by 16)
LVDS
Receiver
is the
input
interface
charge pump with
programmable current
(20, 40, 60, 80 µA)
2nd order passive Low pass filter
with programmable bandwidth
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CML driver is used to drive
50 Ω coaxial cables
PLL Design: Shared Blocks
•
•
The LVDS receiver, the phase frequency detector (PFD), the charge pump, the pass
filter, the CMOS divider, and the CML driver are shared with the 5 Gbps 16:1
serializer. For details of these design blocks please see the poster “A 16:1 serializer
for data transmission at 5 Gbps” presented by Dr. Datao Gong at TWEPP, Paris
France, September, 2009.
The bandwidth of the low pass filter and the current of charge pump are
programmable to suit different applications. The loop bandwidth and the phase margin
are calculated in the following table.
Configuration C0C1C2
Charge pump
gain (µA)
001
010
100
BW
(MHz)
phase
margin
(deg)
BW
(MHz)
phase
margin
(deg)
BW
(MHz)
phase
margin
(deg)
20
0.42
46.33
0.84
46.34
1.68
46.33
40
0.72
56.29
1.44
56.30
2.88
56.31
60
1.02
59.50
2.04
59.50
4.08
59.53
80
1.31
59.99
2.63
59.99
5.25
60.04
5
PLL Design: Layout
Area 1.4 mm x 1.7 mm
6
PLL Design: VCO
Comparison of two common type VCOs
VCO Type
LC-tank based
VCO
Ring oscillatorbased VCO
Power Consumption
Low
High
Frequency
High
Low
Phase noise/jitter performance
Good
Bad
Radiation sensitivity
Small
Large
Tuning range
Narrow
Wide
Chip area
Large
Small
7
PLL Design: VCO Schematic
Cross-coupled
transistors provides
negative resistance,
compensating the
energy loss in the
LC tank
Decoupling
capacitors are
used to improve
the noise
performance
Start-up
circuit
Reference
current source
A NMOS or PMOS transistor with its
source and drain tied together serves a
varactor with monotonic
8 C-V curve and
large tuning range (Cmax/Cmin > 2).
On-chip spiral inductors
with a peak frequency of
5.1 GHz. The Q factor is
simulated to be 21.2 at 5
GHz.
PLL Design: VCO Simulation
• The tuning range is 3.79 – 5.01 GHz at the typical corner and room
temperature and varies less than 8% in all corners and temperature
range.
9
PLL Design: Dividers
• The divider consists of a CML divider
(divide by 2), a CML to CMOS converter,
and a CMOS divider (divide by 8)
• The dividers can work up to 5.1 GHz at all
corners from -40 °C to 85 °C
10
PLL Design: CML Divider
11
PLL Design:
CML to CMOS Converter
12
PLL Performances:
Acquisition Time
The PLL tracks the input frequency and phase after 9 µs
13
PLL Performances:
Deterministic Jitter
The deterministic jitter after tracking (9 µs) is less than 2 ps (peakpeak)
14
PLL Performances:
Random Jitter
The random jitter due to the VCO’s phase noise, the dominant
noise source, is less than 1 ps (RMS) from 10 kHz to 100 MHz
The phase
noise of the
VCO in the
worst case
15
Conclusion:
Simulated Results of the PLL
Tuning range (GHz)
3.78 – 5.01
power consumption (core PLL mW)
104
Area (including pads and decoupling caps, mm2)
1.4 x 1.7
Random Jitter from VCO (RMS, ps)
<1
Deterministic jitter after locking (peak-peak, ps)
2
Acquisition time (μs)
9
16
Conclusion:
Status and Plan
• Fabrication: submitted on August 3, 2009; Chip delivery:
November 28, 2009
• Test: in lab test: December 15, 2009; Radiation test:
February - March, 2010
• Plan: apply this LC-based PLL and design a multichannel 16:1 serializer with each channel working
around 10 Gbps in 2011
17
Acknowledgments
• Grant: US-ATLAS R&D program for the upgrade of the LHC and the
US Department of Energy grant DE-FG02-04ER41299.
• Peter Clarke, Jay Clementson, Yi Kang, Francis M. Rotella, John
Sung, and Gary Wu from Peregrine Semiconductor Corporation for
technical assistance.
• Justin Ross at Southern Methodist University for setting up and
maintaining the software environment.
• Jasoslav Ban, Mauro Citterio, Christine Hu, Sachin Junnarkar,
Valentino Liberali, Paulo Rodrigues Simoes Moreira, Mitch
Newcomer, Quan Sun, Fukun Tang, and Carla Vacchi for technical
assistance and reviewing of this design.
18