DATASHEET
ICS722
LOW COST 27 MHZ 3.3 VOLT VCXO
Description
Features
The ICS722 is a low cost, low-jitter, high-performance 3.3
volt VCXO designed to replace expensive discrete VCXOs
modules. The on-chip Voltage Controlled Crystal Oscillator
accepts a 0 to 3.3 V input voltage to cause the output
clocks to vary by over ±100 ppm. Using IDT’s patented
VCXO techniques, the device uses an inexpensive external
pullable crystal in the range of 16.2 to 28 MHz to produce a
VCXO output clock at that same frequency.
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•
•
•
Packaged in 8-pin SOIC
•
•
•
•
VCXO tuning voltage of 0 to 3.3 V
The frequency of the on-chip VCXO is adjusted by an
external control voltage input into pin VIN. Because VIN is a
high-impedance input, it can be driven directly from an
PWM RC integrator circuit. Frequency output increases
with VIN voltage input. The usable range of VIN is 0 to 3.3
V.
Operational frequency range of 16.2 MHz to 28 MHz
Uses an inexpensive external crystal
On-chip patented VCXO with pull range of 230 ppm
(minimum)
Operating voltage of 3.3 V
12 mA output drive capability at TTL levels
Advanced, low-power, sub-micron CMOS process
NOTE: EOL for non-green parts to occur on 5/13/10
per PDN U-09-01
IDT manufactures the largest variety of Set-Top Box and
multimedia clock synthesizers for all applications. Consult
IDT to eliminate VCXOs, crystals, and oscillators from your
board.
Block Diagram
VDD
VIN
X1
16.2-28MHz
Pullable
Crystal X2
Voltage
Controlled
Crystal
Oscillator
16.2-28MHz Clock
(REFOUT)
GND
IDT™ / ICS™ LOW COST 27 MHZ 3.3 VOLT VCXO
1
ICS722
REV B 110409
ICS722
LOW COST 27 MHZ 3.3 VOLT VCXO
VCXO
Pin Assignment
X1
1
8
X2
VDD
2
7
DC
VIN
3
6
DC
GND
4
5
REFOUT
ICS722
8-Pin (150 mil) SOIC
Pin Descriptions
Pin
Number
Pin
Name
Pin
Type
1
XI
Input
Crystal connection. Connect to the external pullable crystal.
2
VDD
Power
Connect to +3.3 V (0.01µf decoupling capacitor recommended).
3
VIN
Input
Voltage input to VCXO. Zero to 3.3 V signal which controls the
VCXO frequency.
4
GND
Power
Connect to ground.
5
REFOUT
Output
VCXO CMOS level clock output matches the nominal frequency of
the crystal.
6
DC
—
Do not connect anything to this pin.
7
DC
—
Do not connect anything to this pin.
8
X2
Input
IDT™ / ICS™ LOW COST 27 MHZ 3.3 VOLT VCXO
Pin Description
Crystal connection. Connect to a external pullable crystal.
2
ICS722
REV B 110409
ICS722
LOW COST 27 MHZ 3.3 VOLT VCXO
VCXO
External Component Selection
as possible and should be on the same side of the PCB as
the ICS722. There should be no via’s between the crystal
pins and the X1 and X2 device pins. There should be no
signal traces underneath or close to the crystal. See
application note MAN05.
The ICS722 requires a minimum number of external
components for proper operation.
Decoupling Capacitors
Crystal Tuning Load Capacitors
A decoupling capacitor of 0.01µF should be connected
between VDD and GND on pins 2 and 4 as close to the
ICS722 as possible. For optimum device performance, the
decoupling capacitor should be mounted on the component
side of the PCB. Avoid the use of vias in the decoupling
circuit.
The crystal traces should include pads for small fixed
capacitors, one between X1 and ground, and another
between X2 and ground. Stuffing of these capacitors on the
PCB is optional. The need for these capacitors is
determined at system prototype evaluation, and is
influenced by the particular crystal used (manufacture and
frequency) and by PCB layout. The typical required
capacitor value is 1 to 4 pF.
Series Termination Resistor
When the PCB trace between the clock output and the load
is over 1 inch, series termination should be used. To series
terminate a 50Ω trace (a commonly used trace impedance),
place a 33Ω resistor in series with the clock line, as close to
the clock output pin as possible. The nominal impedance of
the clock output is 20Ω.
The procedure for determining the value of these capacitors
can be found in application note MAN05.
Quartz Crystal
The ICS722 VCXO function consists of the external crystal
and the integrated VCXO oscillator circuit. To assure the
best system performance (frequency pull range) and
reliability, a crystal device with the recommended
parameters (shown below) must be used, and the layout
guidelines discussed in the following section shown must be
followed.
The oscillation frequency of a quartz crystal is determined
by its “cut” and by the load capacitors connected to it. The
ICS722 incorporates on-chip variable load capacitors that
“pull” (change) the frequency of the crystal. The crystal
specified for use with the ICS722 is designed to have zero
frequency error when the total of on-chip + stray
capacitance is
14 pF.
Recommended Crystal Parameters:
Initial Accuracy at 25° C
Temperature Stability
Aging
Load Capacitance
Shunt Capacitance, C0
C0/C1 Ratio
Equivalent Series Resistance
±20 ppm
±30 ppm
±20 ppm
14 pf
7 pF Max
250 Max
35 Ω Max
The external crystal must be connected as close to the chip
IDT™ / ICS™ LOW COST 27 MHZ 3.3 VOLT VCXO
3
ICS722
REV B 110409
ICS722
LOW COST 27 MHZ 3.3 VOLT VCXO
VCXO
Absolute Maximum Ratings
Stresses above the ratings listed below can cause permanent damage to the ICS722. These ratings, which are
standard values for IDT commercially rated parts, are stress ratings only. Functional operation of the device at these
or any other conditions above those indicated in the operational sections of the specifications is not implied.
Exposure to absolute maximum rating conditions for extended periods can affect product reliability. Electrical
parameters are guaranteed only over the recommended operating temperature range.
Item
Rating
Supply Voltage, VDD
7V
All Inputs and Outputs
-0.5 V to VDD+0.5 V
Ambient Operating Temperature
0 to +70° C
Storage Temperature
-65 to +150° C
Soldering Temperature
260° C
Recommended Operation Conditions
Parameter
Min.
Typ.
Max.
Units
0
–
+70
°C
+3.45
V
Ambient Operating Temperature
Power Supply Voltage (measured in respect to GND)
+3.15
Reference crystal parameters
Refer to page 3
DC Electrical Characteristics
VDD=3.3 V ±5% , Ambient temperature 0 to +70° C, unless stated otherwise
Parameter
Symbol
Conditions
Operating Voltage
VDD
Output High Voltage
VOH
IOH = -12 mA
Output Low Voltage
VOL
IOL = 12 mA
Output High Voltage (CMOS
Level)
VOH
IOH = -4 mA
Operating Supply Current
IDD
No load
Short Circuit Current
IOS
VIN, VCXO Control Voltage
VIA
IDT™ / ICS™ LOW COST 27 MHZ 3.3 VOLT VCXO
Min.
Typ.
3.145
Units
3.465
V
2.4
V
0.4
VDD-0.4
0
4
Max.
V
V
6
mA
±50
mA
3.3
ICS722
V
REV B 110409
ICS722
LOW COST 27 MHZ 3.3 VOLT VCXO
VCXO
AC Electrical Characteristics
VDD = 3.3 V ±5%, Ambient Temperature 0 to +70° C, unless stated otherwise
Parameter
Symbol
Output Frequency
FO
Crystal Pullability
FP
VCXO Gain
Conditions
Min.
Typ.
Max. Units
16.2
0V< VIN < 3.3 V, Note 1
28
+ 115
MHz
ppm
VIN = VDD/2 + 1 V, Note 1
120
ppm/V
Output Rise Time
tOR
0.8 to 2.0 V, CL=15 pF
1.5
ns
Output Fall Time
tOF
2.0 to 0.8 V, CL=15 pF
1.5
ns
Output Clock Duty
Cycle
tD
Measured at 1.4 V, CL=15 pF
60
%
Maximum Output
Jitter, short term
tJ
CL=15 pF
40
50
110
ps
Note 1: External crystal device must conform with Pullable Crystal Specifications listed on page 3.
Thermal Characteristics
Parameter
Thermal Resistance Junction to
Ambient
Thermal Resistance Junction to Case
Symbol
Conditions
Max. Units
Still air
150
° C/W
θJA
1 m/s air flow
140
° C/W
θJA
3 m/s air flow
120
° C/W
40
° C/W
θJC
Marking Diagram (ICS722MLF)
8
5
5
722MLF
######
YYWW
ICS722M
######
YYWW
1
Typ.
θJA
Marking Diagram (ICS722M)
8
Min.
1
4
4
Notes:
1. ###### is the lot number.
2. YYWW is the last two digits of the year and week that the part was assembled.
3. “LF” denotes Pb (lead) free package.
4. Bottom marking: (origin)
Origin = country of origin if not USA.
IDT™ / ICS™ LOW COST 27 MHZ 3.3 VOLT VCXO
5
ICS722
REV B 110409
ICS722
LOW COST 27 MHZ 3.3 VOLT VCXO
VCXO
Package Outline and Package Dimensions (8-pin SOIC)
Package dimensions are kept current with JEDEC Publication No. 95
8
E
Symbol
Millimeters
Min
Max
Inches
Min
Max
A
A1
B
C
D
E
e
H
h
L
a
1.35
1.75
1.10
0.25
0.33
0.51
0.19
0.25
4.80
5.00
3.80
4.00
1.27 Basic
5.80
6.20
0.25
0.50
0.40
1.27
8°
0°
0.0532 0.0688
0.0040 0.0098
0.013
0.020
0.0075 0.0098
.1890
.1968
0.1497 0.1574
0.050 Basic
0.2284 0.2440
0.010
0.020
0.016
0.050
0°
8°
H
INDEX
AREA
1 2
D
A
h x 45
A1
C
-Ce
B
SEATING
PLANE
L
.10 (.004)
C
Ordering Information
Part / Order Number
722M*
722MT*
722MLF
722MLFT
Marking
Shipping Packaging
Package
see page 5
Tubes
Tape and Reel
Tubes
Tape and Reel
8-pin SOIC
8-pin SOIC
8-pin SOIC
8-pin SOIC
Temperature
0 to +70°
0 to +70°
0 to +70°
0 to +70°
C
C
C
C
*NOTE: EOL for non-green parts to occur on 5/13/10 per PDN U-09-01
“LF” denotes Pb (lead) free package.
While the information presented herein has been checked for both accuracy and reliability, Integrated Device Techonlogy (IDT) assumes
no responsibility for either its use or for the infringement of any patents or other rights of third parties, which would result from its use. No
other circuits, patents, or licenses are implied. This product is intended for use in normal commercial applications. Any other applications
such as those requiring extended temperature range, high reliability, or other extraordinary environmental requirements are not
recommended without additional processing by IDT. IDT reserves the right to change any circuitry or specifications without notice. IDT
does not authorize or warrant any IDT product for use in life support devices or critical medical instruments.
IDT™ / ICS™ LOW COST 27 MHZ 3.3 VOLT VCXO
6
ICS722
REV B 110409
ICS722
LOW COST 27 MHZ 3.3 VOLT VCXO
VCXO
Innovate with IDT and accelerate your future networks. Contact:
www.IDT.com
For Sales
For Tech Support
800-345-7015
408-284-8200
Fax: 408-284-2775
www.idt.com/go/clockhelp
Corporate Headquarters
Integrated Device Technology, Inc.
www.idt.com
© 2006 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice. IDT and the IDT logo are trademarks of Integrated Device
Technology, Inc. Accelerated Thinking is a service mark of Integrated Device Technology, Inc. All other brands, product names and marks are or may be trademarks or registered
trademarks used to identify products or services of their respective owners.
Printed in USA
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