Preliminary Information
T73227
27 MHz VCXO Clock Generator IC
Applications
Crystal-driven clock source for low cost set top boxes and digital multimedia with MPEG video/audio
General Description
The TLSI T73227 is a single-chip, low-jitter Voltage-Controlled-Crystal-Oscillator. The device accepts a 27
MHz fundamental crystal input and produces a low-jitter output at the same frequency. A 0V to +3.3V
control signal is used to fine-tune the output clock frequency in the ±100ppm range. The T73227 is an
excellent replacement for more expensive canned VCXOs.
Features
•
•
•
+3.3V operating voltage
Uses inexpensive pullable
crystals
12mA drive capability at TTL
levels
•
•
•
•
Low Cost
200 ppm pull range (±100 ppm)
8-pin SOIC
and MSOP packages available
Lead-free
packages available
Figure 1. Functional Block Diagram
V
DD
1
V
DD
2
VIN
X2
Load Cap
Control
20 MHz – 30MHz
Pullable Crystal
Output
Buffer
Oscillator
CLK
X1
GND1
GND2
T73227PI
Page
1
Rev A, November 10, 2005
TLSI Incorporated, 770 Park Avenue, Huntington NY 11743
•
(631) 755-7005
•
Fax 631-755-7626
•
www.tlsi.com
T73227
Figure 2. Pin Configuration
X1
V
DD
1
V
IN
GND2
1
2
3
4
8
7
Preliminary Information
X2
GND1
V
DD
2
CLK
T73227
6
5
8-pin SOIC/MSOP
(See pages 4 & 5 for
package outlines
&
ordering information)
Table 1. Pin Description
Name
X1
V
DD
1
V
IN
GND2
CLK
V
DD
2
GND1
X2
Pin No.
1
2
3
4
5
6
7
8
Type
Xi
P
I
P
O
P
P
Xi
Connect to +3.3V.
Description
Crystal connection. Connect to a 20 MHz – 30 MHz pullable crystal
Tuning control input. Zero to +3.3V signal controls the frequency of the VCXO.
Connect to ground.
Clock output
Connect to +3.3V.
Connect to ground.
Crystal connection. Connect to a 20 MHz – 30 MHz pullable crystal.
Legend:
I = Input
O = Output
P = Power supply connection
Xi = Crystal connections
Functional Block Description
The VCXO provides a tunable, low-jitter frequency reference. Loading capacitance for the crystal is
internal to the T73227. No external components (other than the crystal resonator itself) are required for
operation of the VCXO. Tuning of the VCXO frequency is accomplished by varying the voltage on Vin
(Pin 3). The oscillator operates the crystal resonator in the parallel-resonant mode. Crystal warping, or
the “pulling” of the crystal oscillation frequency, is accomplished by altering the effective load
capacitance presented to the crystal by the oscillator circuit. The actual amount that changing the load
capacitance alters the oscillator frequency will be dependent on the characteristics of the crystal as well
as the oscillator circuit itself. Specifically, the motional capacitance of the crystal (usually referred to by
crystal manufacturers as C
1
), the static capacitance of the crystal (C
0
), and the load capacitance (C
L
) of
the oscillator determine the “warping” or “pulling” capability of the crystal in the oscillator circuit. A
simple formula to obtain the warping capability of a crystal oscillator is:
where C
L1
and C
L2
are the two extremes of the applied load capacitance.
EXAMPLE: A crystal with the following parameters is used. With C
1
= 0.025pF, C
0
= 6pF, C
L1
= 10pF,
and C
L2
= 20pF, the tuning range is:
T73227PI
Page
2
Rev A, November 10, 2005
TLSI Incorporated, 770 Park Avenue, Huntington NY 11743
•
(631) 755-7005
•
Fax 631-755-7626
•
www.tlsi.com
T73227
Table 2. Absolute Maximum Ratings
Parameter
Supply voltage, V
DD
Inputs and Clock Outputs
Soldering Temperature
Storage temperature
Input Static Discharge Voltage Protection
Preliminary Information
Conditions
Referenced to GND
Referenced to GND
Max of 10 seconds
Min
-0.5
Typ
Max
5
VDD+0.5
+260
Units
V
V
°C
°C
KV
-65
2
+150
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. These
ratings are stress specifications only and correct functional operation of the device at these or any other conditions
above those listed in the operational sections of the specifications is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect product reliability.
Table 3. Operating Conditions
Parameter
Operating Voltage, V
DD
Ambient Operating Temperature
VCXO control voltage, V
IN
Conditions
Min
+3.135
0
0
Typ
+3.3
Max
+3.465
+70
V
DD
Units
V
°C
V
Table 4. DC Electrical Characteristics
T
A
= 0°C to +70°C, V
DD
= +3.135 V to +3.465 V unless otherwise specified
Parameter
Output High Voltage, V
OH
Output Low Voltage, V
OL
Operating Supply Current, I
DD
Short Circuit Current
Note:
1. Typical values are at V
DD
= +3.3V and +25°C
Condition
I
OH
= -12mA
I
OL
= 12mA
No Load, 27 MHz
CLK output
Min
2.4
Typ
(1)
Max
0.4
Units
V
V
mA
mA
25
±50
35
Table 5. AC Electrical Characteristics
T
A
= 0°C to +70°C, V
DD
= +3.135 V to +3.465 V unless otherwise specified
Symbol
fosc
tr
tf
t
od
t
jit
(pk – pk)
f
PULL
Note:
1.
2.
Parameter
Input Crystal Frequency
Output Clock Rise Time
Output Clock Fall Time
Output Clock Duty Cycle
Period Jitter (Peak to Peak)
Output frequency pullability
Condition
Fundamental
+0.8 to +2.0V, C
L
=10 pF
+2.0 to +0.8V, C
L
=10 pF
At V
DD
/2
C
L
= 10 pF
0V
≤V
IN
≤
+3.3V
Min
20
Typ
(1)
27
Max
30
1.5
1.5
Units
MHz
ns
ns
%
ps
ppm
40
60
150
±100
Typical values are at V
DD
= +3.3V and +25°C
Mil-PRF-55310D 4.8.31.5 Deviation Linearity
T73227PI
Page
3
Rev A, November 10, 2005
TLSI Incorporated, 770 Park Avenue, Huntington NY 11743
•
(631) 755-7005
•
Fax 631-755-7626
•
www.tlsi.com
T73227
Preliminary Information
Table 6. Pullable Crystal Specifications
Parameter
Crystal Resonator Frequency
Crystal Loading Capacitance (AT Cut)
Capacitance Ratio (crystal gamma)
Equivalent Series Resistance
Symbol
f
xtal
C
L
C
O
/C
1
ESR
Value
27 MHz (typ)
20 pF (typ)
240 max
50Ω max
Figure 3. Package Outline (8-pin SOIC)
T73227PI
Page
4
Rev A, November 10, 2005
TLSI Incorporated, 770 Park Avenue, Huntington NY 11743
•
(631) 755-7005
•
Fax 631-755-7626
•
www.tlsi.com
T73227
Figure 4. Package Outline (8-pin MSOP)
Preliminary Information
Table 7. Ordering Information
No. of
Pins
8
8
8
8
8
8
8
8
Part Number
T73227-SO8
T73227-SO8-TNR
T73227-SO8-LF
T73227-SO8-LF-TNR
T73227-MO8
T73327-MO8-TNR
T73327-DIE
T73327-DPW
Marking
T73227
T73227
T73227●
T73227●
T73227
T73227
N/A
N/A
Shipping/Packaging
Tubes
Tape & Reel
Tubes
Tape & Reel
Tubes
Tape & Reel
Die in Waffle Pack
Die in Probed Wafer
Package
SOIC
SOIC
SOIC (Pb-Free)
SOIC (Pb-Free)
MSOP
MSOP
N/A
N/A
Temperature
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
T73227PI
Page
5
Rev A, November 10, 2005
TLSI Incorporated, 770 Park Avenue, Huntington NY 11743
•
(631) 755-7005
•
Fax 631-755-7626
•
www.tlsi.com
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