MK3721SLFTR [IDT]
Clock Generator, 28MHz, CMOS, PDSO8, SOIC-8;
| 型号： | MK3721SLFTR |
| 厂家： | 
INTEGRATED DEVICE TECHNOLOGY |
| 描述： | Clock Generator, 28MHz, CMOS, PDSO8, SOIC-8 光电二极管 |
| 文件： | 总6页 (文件大小：113K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MK3721
LOW COST 16.2 TO 28 MHZ 3.3 VOLT VCXO
Description
Features
The MK3721 series of devices includes the original
MK3721S and the new MK3721D. The MK3721D is a
drop-in replacement for the MK3721S device.
Compared to the earlier device, the MK3721D offers a
wider operating frequency range and improved power
supply noise rejection.
• MK3721D is a drop-in replacement for the earlier
MK3721S device
• Packaged in 8-pin SOIC
• Operational frequency range of 16.2 MHz to 28 MHz
• Uses an inexpensive external crystal
• On-chip patented VCXO with pull range of 200 ppm
The MK3721 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 ±100 ppm. Using
ICS’ 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.
(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, sub-micron CMOS process
• For frequencies between 1 MHz and 8 MHz, use the
MK3713D. For higher than 28 MHz, use the
MK3732-05.
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.
• Available in a lead-free package
MK3721D is recommended for new designs.
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
16.2 to 28 MHz
Pullable
Controlled
Crystal
16.2 to 28 MHz Clock
(REFOUT)
Crystal
Oscillator
X2
GND
MDS 3721 E
1
Revision 103003
Integrated Circuit Systems ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com
MK3721
LOW COST 16.2 TO 28 MHZ 3.3 VOLT VCXO
Pin Assignment
X 1
V D D
V I N
8
7
6
5
1
2
3
4
X 2
D C
R E F O U T
D C
G N D
M K 3 7 2 1 S
M K 3 7 2 1 D
8 - P i n ( 1 5 0 m i l ) S O I C
Pin Descriptions
Pin
Pin
Pin
Pin Description
Number
Name
Type
1
2
3
XI
Input
Crystal connection. Connect to the external pullable crystal.
VDD
VIN
Power Connect to +3.3 V (0.01µf decoupling capacitor recommended).
Input
Voltage input to VCXO. Zero to 3.3 V signal which controls the
VCXO frequency.
4
5
6
GND
DC
Power Connect to ground.
--
Do not connect to this pin.
REFOUT
Output VCXO CMOS level clock output matches the nominal frequency of
the crystal.
7
8
DC
X2
--
Do not connect anything to this pin.
Input
Crystal connection. Connect to a pullable 16.2 to 28 MHz crystal.
MDS 3721 E
2
Revision 103003
Integrated Circuit Systems ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com
MK3721
LOW COST 16.2 TO 28 MHZ 3.3 VOLT VCXO
variable load capacitors that “pull” (change) the
frequency of the crystal. The crystal specified for use
with the MK3721 is designed to have zero frequency
error when the total of on-chip + stray capacitance is
14 pF.
External Component Selection
The MK3721 requires a minimum number of external
components for proper operation.
Decoupling Capacitors
Recommended Crystal Parameters:
A decoupling capacitor of 0.01µF should be connected
between VDD and GND on pins 2 and 4 as close to the
MK3721 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.
Initial Accuracy at 25°C
Temperature Stability
Aging
Load Capacitance
Shunt Capacitance, C0
C0/C1 Ratio
±20 ppm
±30 ppm
±20 ppm
14 pf
7 pF Max
250 Max
35 Ω Max
Equivalent Series Resistance
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 external crystal must be connected as close to the
chip as possible and should be on the same side of the
PCB as the MK3721. 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.
Crystal Tuning Load Capacitors
Quartz Crystal
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.
The MK3721 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 MK3721 incorporates on-chip
The procedure for determining the value of these
capacitors can be found in application note MAN05.
MDS 3721 E
3
Revision 103003
Integrated Circuit Systems ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com
MK3721
LOW COST 16.2 TO 28 MHZ 3.3 VOLT VCXO
Absolute Maximum Ratings
Stresses above the ratings listed below can cause permanent damage to the MK3721. 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
7 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 3721 E
4
Revision 103003
Integrated Circuit Systems ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com
MK3721
LOW COST 16.2 TO 28 MHZ 3.3 VOLT VCXO
DC Electrical Characteristics
VDD=3.3V ±5% , 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 = 3.3V ±5%, Ambient Temperature 0 to +70° C, unless stated otherwise
Parameter
Output Frequency
MK3721D
Symbol
Conditions
Min. Typ. Max. Units
F
F
16.2
28
MHz
MHz
O
O
MK3721S
24 MHz
24
Crystal Pullability
MK3721D
F
F
0V< VIN < 3.3 V, Note 1
0V< VIN < 3.3 V, Note 1
+ 115
+ 100
ppm
ppm
P
P
MK3721S
VCXO Gain
MK3721D
VIN = VDD/2 + 1 V, Note 1
VIN = VDD/2 + 1 V, Note 1
120
140
ppm/V
ppm/V
ns
MK3721S
Output Rise Time
Output Fall Time
Output Clock Duty Cycle
t
0.8 to 2.0 V, C =15 pF
1.5
1.5
60
OR
L
t
2.0 to 0.8 V, C =15 pF
ns
OF
L
t
Measured at 1.4V, C =15 pF
40
50
%
D
L
Maximum Output Jitter,
short term
t
C =15 pF
110
ps
J
L
Note 1: External crystal device must conform with Pullable Crystal Specifications listed on page 3.
MDS 3721 E
5
Revision 103003
Integrated Circuit Systems ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com
MK3721
LOW COST 16.2 TO 28 MHZ 3.3 VOLT VCXO
Package Outline and Package Dimensions (8-pin SOIC)
Package dimensions are kept current with JEDEC Publication No. 95
Millimeters
Inches
Min Max
Symbol
Min
Max
1.75
0.25
0.51
0.25
5.00
4.00
A
A1
B
C
D
E
e
1.35
1.10
0.33
0.19
4.80
3.80
0.0532 0.0688
0.0040 0.0098
0.013
0.0075 0.0098
.1890 .1968
0.020
Index
Area
E
H
0.1497 0.1574
0.050 Basic
1.27 Basic
H
h
L
5.80
0.25
0.40
0°
6.20
0.50
1.27
8°
0.2284 0.2440
0.010
0.016
0°
0.020
0.050
8°
Pin 1
a
D
h x 450
A
Q
c
e
b
Ordering Information
Part / Order Number
(Note 1)
Marking
Shipping
packaging
Package
Temperature
MK3721D
MK3721D
MK3721D
MK3721DL
MK3721DL
MK3721S
MK3721S
Tubes
8-pin SOIC
8-pin SOIC
8-pin SOIC
8-pin SOIC
8-pin SOIC
8-pin SOIC
0 to +70° C
0 to +70° C
0 to +70° C
0 to +70° C
0 to +70° C
0 to +70° C
MK3721DTR
MK3721DLF
MK3721DLFTR
MK3721S
Tape and Reel
Tubes
Tape and Reel
Tubes
MK3721STR
Tape and Reel
Note 1: MK3721D is recommended for new designs.
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 3721 E
6
Revision 103003
Integrated Circuit Systems ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com
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