2001-04-02 Page
1
MDST-0006-03
Vaishali Semiconductor 1300 White Oaks Road, Ste. 200 Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
Applications
= Set-top boxes
= Telecom switching
= Oscillator replacement
= MPEG Video clock source
General Description
The Vaishali VT73227 is a single-chip, low-jitter Voltage-Controlled-Crystal-Oscillator. The device accepts
a 27 MHz, 20 pF (pull range of 200 ppm) crystal input, and produces a low jitter output at the same
frequency. A 0 to 3.0V control signal is used to fine tune the output clock frequency in the 100ppm range.
Features
= 3.3V operating voltage
= Uses inexpensive pullable crystal
= 12mA drive capability at TTL levels
= On-chip oscillator with 200 ppm pull
range (100 ppm)
= 8 pin SOIC package
VT73227
VCXO
(Voltage-Controlled Crystal Oscillator)
27 MHz 3.3V
Figure 1. Functional Block Diagram
CLK1
VDD2
X2
Load Cap Control
Output
Buffer
Load
Caps
VDD1
27 MHz
Pullable
Crystal
VIN
X1
GND1
GND2
Oscillator
VT73227
2001-04-02 Page
2
MDST-0006-03
Vaishali Semiconductor 1300 White Oaks Road, Ste. 200 Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
Figure 2. Pin Configuration
Table 1. Pin Description
Name Pin
# Type
Description
X1
1
Xi
Crystal connection. Connect to a 27 MHz pullable crystal
VDD1 2
P Core
V
DD
. Connect to 3.3V
VIN
3
I
Voltage input to VCXO. Zero to 3.3V signal controls the frequency of the VCXO.
GND2
4
P
Connect to ground.
CLK
5
O
Clock output
VDD2
6
P
Pad driver V
DD
. Connect to 3.3V
GND1
7
P
Connect to ground.
X2
8
Xi
Crystal connection. Connect to a 27 MHz pullable crystal.
Legend: I = Input
O = Output
P = Power supply connection
Xi = Crystal connections.
Table 2. Absolute Maximum Ratings
Parameter Conditions
Min
Typ
Max
Units
Supply voltage, V
DD
Referenced to GND
7
V
Inputs and Clock Outputs
Referenced to GND
-0.5
VDD+0.5
V
Soldering Temperature
Max of 10 seconds
260
C
Storage temperature
-65
150
C
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 Conditions
Min
Typ
Max
Units
Operating Voltage, V
DD
3.15
3.3
3.45
V
Input High Voltage, V
IH
, X1 pin only
2.5
V
Input Low Voltage, V
IL
, X1 pin only
0.4
V
Operating Temperature
0
70
C
Input crystal accuracy
30
ppm
VCXO control voltage, V
IN
0
3.3
V
X1
X2
VDD1
VDD2
VIN
GND2
GND1
CLK
VT73227
8 pin (150 mil) SOIC
2
3
4
5
6
7
8
1
VT73227
2001-04-02 Page
3
MDST-0006-03
Vaishali Semiconductor 1300 White Oaks Road, Ste. 200 Campbell CA 95008 Ph. 408.377.6060 Fax 408.377.6063
Table 4. DC Electrical Characteristics
T
A
= 0
C to +70
C, V
DD
= 3.15 V to 3.45 V
Parameter Condition
Min
Typ
(1)
Max Units
Output High Voltage, V
OH
I
OH
=-12mA 2.4
V
Output Low Voltage, V
OL
I
OL
=12mA 0.4
V
Operating Supply Current, I
DD
No
Load
25
mA
Short Circuit Current
Each output
85
mA
Input Capacitance
7
pF
Note
:
1. Typical values are at V
DD
= 3.3V and 25C
Table 5. AC Electrical Characteristics
T
A
= 0
C to +70
C, V
DD
= 3.15 V to 3.45 V
Symbol Parameter Condition
Min
Typ
Max
Units
fosc
Input Crystal Frequency
27
MHz
tr
Output Clock Rise Time
0.8 to 2.0V
1.5
ns
tf
Output Clock Fall Time
2.0 to 0.8V
1.5
ns
t
od
Output Clock Duty Cycle
At V
DD
/2 40
60
%
t
jit
(pk pk)
Maximum Absolute Jitter
(Peak to Peak)
150
ps
Output pullability
0V <V
IN
<3.3V 100
ppm
Note
:
1. Typical values are at V
DD
= 3.3V and 25C
Table 6 Pullable Crystal Specifications
Parameter Symbol
Value
Correlation (Load) Capacitance
C
L
20pF
Capacitance Ratio
C
O
/C
1
240
max
ESR
50
max
Initial Accuracy
30ppm
Temperature and Aging Stability
50ppm
Ordering Information
VT73227
Part Number
Marking
Shipping/Packaging
No. of Pins Package
Temperature
VT73227-S1 VT73227-S1
Tubes
8
SOIC 0
o
C to +70
o
C
VT73227-S1X
VT73227-S1
Tape & Reel
8
SOIC
0
o
C to +70
o
C
VT73227-/D -
Die
0
o
C to +70
o
C
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