ICS3821M [IDT]
Clock Generator, 36MHz, CMOS, PDSO8, 0.150 INCH, SOIC-8;
| 型号： | ICS3821M |
| 厂家： | 
INTEGRATED DEVICE TECHNOLOGY |
| 描述： | Clock Generator, 36MHz, CMOS, PDSO8, 0.150 INCH, SOIC-8 时钟 光电二极管 外围集成电路 晶体 |
| 文件： | 总6页 (文件大小：132K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
PRELIMINARY INFORMATION
ICS3821
HIGH PERFORMANCE VCXO
Description
Features
The ICS3821 is a 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 130 ppm. Using ICS’
patented VCXO techniques, the device uses an
inexpensive external pullable crystal in the range of 12
to 36 MHz to produce a VCXO output clock at that
same frequency.
• Packaged in 8-pin SOIC
• Operational frequency range of 12 MHz to 36 MHz
• Uses an inexpensive external crystal
• On-chip patented VCXO with pull range of 130 ppm
(minimum)
• VCXO tuning voltage of 0 to 3.3 V
• Operating voltage of 3.3 V
• 12 mA output drive capability at TTL levels
• Advanced, low-power, CMOS process
• Available in a lead-free package
ICS manufactures the largest variety of Set-Top Box
and multimedia clock synthesizers for all applications. If
more clock outputs are needed, see the MK3732 or
MK377x family of parts. Consult ICS to eliminate
VCXOs, crystals, and oscillators from your board.
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.
Block Diagram
VDD
VIN
X1
Voltage
Controlled
Crystal
12 to 36 MHz
Pullable
12 to 36 MHz
Clock (REFOUT)
Crystal
Oscillator
X2
GND
OE
MDS 3821 A
1
Revision 050905
Integrated Circuit Systems ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com
PRELIMINARY INFORMATION
ICS3821
HIGH PERFORMANCE VCXO
Pin Assignment
X 1
D C
8
7
6
5
1
2
3
4
X 2
O E
V I N
G N D
V D D
R E F O U T
8 - P i n ( 1 5 0 m i l ) S O I C
Pin Descriptions
Pin
Number
Pin
Name
Pin
Pin Description
Type
Input
—
1
2
3
X1
DC
VIN
Crystal connection. Connect to the external pullable crystal.
Do not connect anything to this pin.
Input
Voltage input to VCXO. Zero to 3.3 V signal which controls the
VCXO frequency.
4
5
GND
Power Connect to ground.
REFOUT
Output VCXO CMOS level clock output matches the nominal frequency of
the crystal.
6
7
VDD
OE
Power Connect to +3.3 V (0.01µf decoupling capacitor recommended).
Input
Output Enable. Active high input—1: Enable; 0: Hi-Z (Disable).
Internal pull-up.
8
X2
Input
Crystal connection. Connect to a pullable 12 to 36 MHz crystal.
MDS 3821 A
2
Revision 050905
Integrated Circuit Systems ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com
PRELIMINARY INFORMATION
ICS3821
HIGH PERFORMANCE VCXO
Recommended Crystal Parameters:
External Component Selection
Initial Accuracy at 25°C
Temperature Stability
Aging
20 ppm
30 ppm
20 ppm
10 pf
7 pF Max
250 Max
35 Ω Max
The ICS3821 requires a minimum number of external
components for proper operation.
Load Capacitance
Shunt Capacitance, C0
C0/C1 Ratio
Decoupling Capacitors
A decoupling capacitor of 0.01µF should be connected
between VDD and GND on pins 4 and 6 as close to the
ICS3821 as possible. For optimum device
Equivalent Series Resistance
performance, the decoupling capacitor should be
mounted on the component side of the PCB. Avoid the
use of vias in the decoupling circuit.
The external crystal must be connected as close to the
chip as possible and should be on the same side of the
PCB as the ICS3821. 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.
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.
Crystal Tuning Load Capacitors
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.
Quartz Crystal
The ICS3821 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 procedure for determining the value of these
capacitors can be found in application note MAN05.
The ICS3821 incorporates on-chip variable load
capacitors that pull (change) the frequency of the
crystal. The crystal specified for use with the ICS3821
is designed to have zero frequency error when the total
of on-chip + stray capacitance is
10 pF.
MDS 3821 A
3
Revision 050905
Integrated Circuit Systems ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com
PRELIMINARY INFORMATION
ICS3821
HIGH PERFORMANCE VCXO
Absolute Maximum Ratings
Stresses above the ratings listed below can cause permanent damage to the ICS3821. These ratings,
which are standard values for ICS 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
All Inputs and Outputs
5 V
-0.5 V to VDD+0.5 V
0 to +70°C
Ambient Operating Temperature
Storage Temperature
-65 to +150°C
260°C
Soldering Temperature
Recommended Operation Conditions
Parameter
Min.
Typ.
Max.
+70
Units
°C
Ambient Operating Temperature
Power Supply Voltage (measured in respect to GND)
Reference crystal parameters
0
–
+3.15
+3.45
V
Refer to page 3
MDS 3821 A
4
Revision 050905
Integrated Circuit Systems ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com
PRELIMINARY INFORMATION
ICS3821
HIGH PERFORMANCE VCXO
DC Electrical Characteristics
VDD=3.3 V ±±% , Ambient temperature 0 to +70°C, unless stated otherwise
Parameter
Symbol
Conditions
Min.
3.15
2.4
Typ.
Max.
Units
Operating Voltage
VDD
3.45
V
V
V
V
Output High Voltage
Output Low Voltage
V
I
I
I
= -12 mA
= 12 mA
= -4 mA
OH
OH
OL
OH
V
0.4
OL
Output High Voltage (CMOS
Level)
V
VDD-0.4
OH
Operating Supply Current
Short Circuit Current
IDD
No load
6
mA
mA
V
I
50
OS
VIN, VCXO Control Voltage
V
0
3.3
IA
AC Electrical Characteristics
VDD = 3.3 V ±±%, Ambient Temperature 0 to +70° C, unless stated otherwise
Parameter
Output Frequency
Crystal Pullability
VCXO Gain
Symbol
Conditions
Min. Typ. Max. Units
F
12
36
MHz
ppm
ppm/V
ns
O
F
0V< VIN < 3.3 V, Note 1
+ 130
P
VIN = VDD/2 + 1 V, Note 1
115
Output Rise Time
Output Fall Time
Output Clock Duty Cycle
t
20% to 80%, C =15 pF
1.5
1.5
60
OR
L
t
80% to 20%, C =15 pF
ns
OF
L
t
Measured at 1.4 V, C =15 pF
40
50
60
%
D
L
Maximum Output Jitter,
Peak-to-peak
t
C =15 pF
75
ps
J
L
Phase Noise Relative to
Carrier for 35.328 MHz
1 kHz
-115
-140
-155
dBc/Hz
dBc/Hz
dBc/Hz
10 kHz
100 kHz
Note 1: External crystal device must conform with Pullable Crystal Specifications listed on page 3.
MDS 3821 A
5
Revision 050905
Integrated Circuit Systems ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com
PRELIMINARY INFORMATION
ICS3821
HIGH PERFORMANCE VCXO
Package Outline and Package Dimensions (8-pin SOIC)
Package dimensions are kept current with JEDEC Publication No. 95
Millimeters
Inches*
8
Symbol
Min
1.35
0.10
0.33
0.19
4.80
3.80
Max
1.75
0.25
0.51
0.25
5.00
4.00
Min
Max
A
A1
B
C
D
E
e
.0532
.0040
.013
.0075
.1890
.1497
.0688
.0098
.020
.0098
.1968
.1574
E
H
INDEX
AREA
1.27 BASIC
0.050 BASIC
1
2
H
h
L
5.80
0.25
0.40
0°
6.20
.2284
.010
.016
0°
.2440
.020
.050
8°
0.50
1.27
8°
D
α
*For reference only. Controlling dimensions in mm.
A
h x 45
A1
C
- C -
e
SEATING
PLANE
B
L
.10 (.004)
C
Ordering Information
Part / Order Number
ICS3821M
Marking
ICS3821M
ICS3821M
ICS3821ML
ICS3821ML
Shipping Packaging
Tubes
Package
8-pin SOIC
8-pin SOIC
8-pin SOIC
8-pin SOIC
Temperature
0 to +70° C
0 to +70° C
0 to +70° C
0 to +70° C
ICS3821MT
Tape and Reel
Tubes
Tape and Reel
ICS3821MLF
ICS3821MLFT
Parts that are ordered with a "LF" suffix to the part number are the Pb-Free configuration and are RoHS compliant.
While the information presented herein has been checked for both accuracy and reliability, Integrated Circuit Systems (ICS)
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 ICS. ICS reserves the right to change any
circuitry or specifications without notice. ICS does not authorize or warrant any ICS product for use in life support devices or
critical medical instruments.
MDS 3821 A
6
Revision 050905
Integrated Circuit Systems ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com
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