Think of Introduction to Crystal wwwtxccorpcom TXC Confidential amp Proprietary 1 TXC Confidential amp Proprietary 2 Quartz Crystal Basic Structure 33 45 67 21 21 00 ID: 377831
Download Presentation The PPT/PDF document "Think of Frequency" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Think of Frequency
Think of
Introduction to Crystal
www.txccorp.com
TXC Confidential & Proprietary |
1Slide2
TXC Confidential & Proprietary |
2
Quartz Crystal Basic: Structure
33
45
67
21
21
00
79
67
45
12
21
45
67
33
88
55
79
00
88
79
00
88
Silicon
Oxygen
Domain
Wall
X
Y
Z
Constitutes :
Silicon Dioxide, SiO
2
Crystal System
:
Trigonal
32
Melting Point :
~ 1,750 degree C @ 1
atm
Hardness :
~ 7.2
Mohs
@ 1
atm
Nature Quartz
Synthetic QuartzSlide3
TXC Confidential & Proprietary |
3
Si
4+
O
2-
O
2-
Si
4+
O
2-
O
2-
-
-
+
+
Si
4+
O
2-
O
2-
+
+
-
-
- Piezoelectric Effect
- Reverse Piezoelectric Effect
Si
4+
O
2-
O
2-
Electric neutral
When a pulling-outward force
is applied on O
2-, a positive electric field is induced.When a pushing-inward forceis applied on O
2-, a negative electric field is induced.Electric neutral
- -
- - - -
Si
4+
O
2-
O2-
+
+
+
+
+
+
+
+
+
+
+
+
-
-
-
-
- -
- - -
- - -
-
- - - -
-
+
+
+
+
+
+
+
+
+
+
+
+
Si
4+
O
2-
O
2-
When
an
electric field
is applied,
the
induced electric filed is
generated,and force the O2- moving outward.
When an electric field is applied, the induced electric filed is generated,and force
the O2- moving inward.
Quartz Crystal Basic: Piezoelectricity Slide4
TXC Confidential & Proprietary |
4
Natural
Quartz
Synthetic Quartz
Quartz Crystal Basic:
Natural vs. SyntheticSlide5
TXC Confidential & Proprietary |
5
AUTOCLAVE
HYDROTHERMAL METHOD
RAW MATERIAL
：
Silica HIGH TEMPERATURE： ~ 350 ~ 400 ℃
HIGH
PRESSURE
：
~ 900 ~ 1,000 Kg / cm
2
HIGH TEMP. STABILITY
：
± 3 ℃
LONG GROWTH TIME
：
1 ~ 6 Month
HIGH PURITY Infra-Red Absorption (IRA)
： 3585 CM-1
Crystal Growth
Region (~300
℃
)
Dissolving
Region (~400
℃)
Quartz Crystal Basic: Synthetic QuartzSlide6
TXC Confidential & Proprietary |
6
Quartz Crystal Basic:
Synthetic Quartz
Grown quartz bars from autoclave
Moving new autoclave to the factorySlide7
TXC Confidential & Proprietary |
7
Wire Sawing
Quartz Bar
A
1
2
3
4
5
6
7
8
9
0
EN
B
C
D
Lapping
22.1372
Wafer
Frequency
Processing time: <10 days
Manufacturing Process: From Bar to BlankSlide8
TXC Confidential & Proprietary |
8
Low Frequency
CT : +38
0
DT : -52
0
ET : +66
0
FT :
-
57
0
High
Frequency
AT
: +35
0
12’
BT : -49
0
Many cutting
angles for various applications.
AT
cutting is one of the most popular and applicable angles.
X
m
r
R
m
Z
r
R
m
X
r
Z
X
NT
GT
DT
BT
AT
CT
+2
0
+5
0
X
+5
0
+5
0
+50
0
+2
0
X
Y
Cutting AngleSlide9
TXC Confidential & Proprietary |
9
Cutting Angle: FT Characteristic of Different C
uts
20
40
0
- 20
- 40
- 60
- 80
- 100
- 160
- 120
- 140
- 40
- 20
0
20
40
60
80
Frequency Change in ppm
Temperature (
º
C )
AT
AT
GT
GT
DT
DT
XY
XY
CT
CTSlide10
TXC Confidential & Proprietary |
10
Cutting Angle: AT-Cut FT Characteristic
r
m
R
R
R
R
r
m
Y
Z
AT-cut
BT-cut
49
o
35¼
o
-1’
0
’
1
’
2
’
3
’
4
’
5
’
6
’
7
’
8
’
-1
’
0
’
1
’
2
’
3
’
4
’
5
’
6
’
7
’
8
’
Y-bar quartz
Z
25
20
15
10
5
0
-5
-10
-15
-20
-25
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
f
f
(ppm)
Temperature (
o
C
)
= 35
o
12.5’+ , = 0 for
fundamental mode
plano-plano
AT-cut
= 35
o
20’ + , = 0
for 5th overtone
AT-cutSlide11
TXC Confidential & Proprietary |
11
Thickness of Blank: Determines Frequency
A
l
AT Cut Crystal
- Resonance frequency is determined by thickness of blank.
- For a 20 MHz crystal, the thickness is around 83um.
(
The diameter of human hair is around
50~80um)
- The thinner the blank, the higher the frequency is.
Note
: The constant of 1670 is not the
exact number
for AT cutting. This number ranges from 1650 ~ 1685 depends on
the
dimension and thickness of the AT quartz plate.
FrequencySlide12
TXC Confidential & Proprietary |
12
Structure and Manufacturing Process
IC Die Bonding
Wire Bonding
Blank Cleaning
Base Plating
Frequency Adj.
Final Testing
Marking
Taping
Seam Sealing
Mechanical Testing
Blank Auto-Mounting
Crystal
Oscillator
Oscillator
■
40.000
TXC CM211
■
24.576
TXC CN001
Crystal
Metal Lid
Plated Blank
Ceramic Package
(Bottom)
Ceramic Package
(Top)
Oscillation IC
Processing time: <10 daysSlide13
TXC Confidential & Proprietary |
13
Specification
Tips of Defining the Specification of a Crystal:
1. Determine the Nominal Frequency
Ex: 8Z Series (2.5x2.0 mm)
2. Choose
the Load
Capacitance
3.
Define the Frequency Tolerance and Stability
4.
Define the Drivel
Level, Effective Resistance, and Shunt capacitance C
0Slide14
TXC Confidential & Proprietary |
14
Load Capacitance Choosing : C
L vs. Trim Sensitivity
Load Capacitance: 06~10 pF, high trim sensitivity: unstable, but tunable
Load
Capacitance: 16~30 pF, low trim sensitivity: stable, but hardly tunable
Ex. 3.2 x 2.5mm, 12.0 MHz, CL=8.0
pFSlide15
TXC Confidential & Proprietary |
15
Package Size vs
Drive Level & Resistance
Ex: 25MHz Crystal
Slide16
TXC Confidential & Proprietary |
16
Worldwide Lab Facilities
Three FAE locations with RD level testing equipment for Oscillation Circuit/Oscillator
When the assistance is needed, please contact account manager to arrange the test in different locations
Ningbo, China
Taoyuan
, Taiwan
San Jose, USA Slide17
TXC Confidential & Proprietary |
17
Services
Unit Analysis
Crystal
& Tuning Fork
Electrical Testing
(S&A 250B)
SPICE Model (RLC Model)
Oscillator
Electrical Testing
Testing
Temperature
：
-73
˚C ~175
˚CBoard Evaluation and Circuit Matching
Accuracy of Frequency
Drive Level
Negative Resistance
Start-up Time Operating Temperature
Testing (Stability)
Failure Part AnalysisInitial FA report Slide18
TXC Confidential & Proprietary |
18
Measuring Instruments and Test EquipmentSlide19
TXC Confidential & Proprietary |
19
Purpose of Matching
Mismatched Circuit:
None or inconsistent oscillation
Long startup timeBad temperature performanceCrystal resonator damaging
Bad jitter and frequency errorOthersMeasurements:
Accuracy of
Frequency
Drive Level
Negative Resistance
Startup time
Operating Temperature Test (Stability)Slide20
Think of Frequency
Think of
Introduction to Crystal Oscillators
www.txccorp.com
TXC Confidential & Proprietary |
20Slide21
TXC Confidential & Proprietary |
21
Crystal Oscillators
1.
Least integrated circuitry inside IC
2.
Best noise performance in LSI-based crystal oscillator
3.
±15 PPM
level temperature stability
4.
±10 PPM level frequency accuracy based on physical tuning capability
Amplifier
Buffer
Crystal
C
d
C
g
GND
F
out
VDD
Simple Packaged Crystal Oscillator (XO)
No Voltage Tunable CapabilitySlide22
TXC Confidential & Proprietary |
22
1.
Integrated
varactor inside
IC
2.
The tunable range of varactor and the load sensitivity of X'tal resonator influences the tunable range of VCXO
3.
±15
PPM level temperature stability
4.
±10 PPM level frequency accuracy based on physical tuning capability
Tunable Range over Temp.
VC
VC-plus
VC-minus
Amplifier
Buffer
(CMOS/
Differenial
)
F
out
VDD
Crystal
C
d
C
g
Varactor
V
C
GND
Voltage-Controlled Crystal Oscillator (VCXO)
Crystal OscillatorsSlide23
Tunable Range over Temp.
TXC Confidential & Proprietary |
23
Amplifier
Buffer
F
out
VDD
Crystal
C
d
C
g
Varactor
VC
Temperature Sensor and Compensation Circuitry
GND
1.
Integrated varactor
& compensation
circuit inside IC
2.
The tunable range of varactor and the load sensitivity of X'tal resonator influences the tunable range of VCXO
3.
<±2.5
to
±
0.28
(S3-TCXO)
PPM
level temperature stability
4.
<±2.5 PPM
level frequency accuracy based on physical tuning capability
Temperature-Compensated Crystal Oscillator (TCXO)
Crystal Oscillators
25 ̊C
T
F
Crystal
IC Compensated
Result
≦
2.5
ppm
≦
0.3 ppm (Stratum 3 TCXO)Slide24
TXC Confidential & Proprietary |
24
Oven
Amplifier
Buffer
F
out
V
dd
Crystal
C
d
C
g
Varactor
V
c
Temperature Sensor
Oven Control Circuit
1.
Discrete
electrical
components
&
oven controlled
circuit
2.
The tunable range of
varactor
and the load sensitivity of
X'tal
resonator influences the tunable range of VCXO
3.
<±
0.1
PPM
level temperature stability
4.
<±
0.1
PPM
level frequency accuracy based on physical tuning capability
Tunable Range over Temp.
(Depends on crystal cut)
Oven-Controlled Crystal Oscillator (OCXO)
Crystal OscillatorsSlide25
Less than 1/3 of CMOS voltage swing
Less than 1/6 of CMOS voltage swing
TXC Confidential & Proprietary |
25
Differential Output
CMOS (Single-ended)
Differential
CMOS: Single-ended
Differential
*
: Dual-ended (same frequency)
Advantage of Differential Output
Low
voltage swing
Better
noise rejection
*:
3 kinds of differential output that TXC is using:
LVPECL, LVDS, HCSLSlide26
TXC Confidential & Proprietary |
26
Thank you