ICST ICS650R-21 System peripheral clock source Datasheet

PRELIMINARY INFORMATION
ICS650-21
System Peripheral Clock Source
Description
Features
The ICS650-21 is a low cost, low jitter, high
performance clock synthesizer for system
peripheral applications. Using analog/digital
Phase-Locked Loop (PLL) techniques, the device
accepts a parallel resonant 25 MHz crystal input to
produce up to eight output clocks. The device
provides clocks for PCI, SCSI, Fast Ethernet,
Ethernet, USB, and AC97. The user can select one
of three USB frequencies, and also one of two
AC97 audio frequencies. The OE pin puts all
outputs into a high impedance state for board level
testing. All frequencies are generated with less than
one ppm error, meeting the demands of SCSI and
Ethernet clocking.
The ICS650 can be mask customized to produce
any frequencies from 1 to 150 MHz.
Block Diagram
PSEL1:0
Clock
Synthesis
Circuitry
USEL
X1/ICLK
Crystal
Oscillator
X2
Output
Buffer
2
ASEL
25 MHz
crystal
or clock
• Packaged in 20 pin tiny SSOP (QSOP)
• Lower jitter version of ICS650-01
• Operating VDD of 3.3V or 5V
• Zero ppm synthesis error in all clocks
• Inexpensive 25 MHz crystal or clock input
• Provides Ethernet and Fast Ethernet clocks
• Provides SCSI clocks
• Provides PCI clocks
• Selectable AC97 audio clock
• Selectable USB clock
• OE pin tri-states the outputs for testing
• Selectable frequencies on three clocks
• Duty cycle of 45/55 for Processor clock and Audio
clock
• Advanced, low power CMOS process
3
Processor Clocks
(Fast Ethernet,
SCSI, PCI )
Output
Buffer
Audio Clock
Output
Buffers
USB Clock
Output
Buffers
20 MHz
Output
Buffer
25 MHz
Output Enable (all outputs)
1
Revision 010301
Integrated Circuit Systems, Inc. • 525 Race Street • San Jose •CA•95126• (408) 295-9800tel • www.icst.com
MDS 650-21 A
PRELIMINARY INFORMATION
ICS650-21
System Peripheral Clock Source
Pin Assignment
Processor Clock (MHz)
USEL
1
20
PSEL1
X2
2
19
PSEL0
X1/ICLK
3
18
PCLK2
VDD
4
17
PCLK3
VDD
5
16
VDD
GND
6
15
ASEL
UCLK
7
14
GND
20M
8
13
OFF/14.318M
ACLK
9
12
PCLK1
10
11
OE
25M
20 pin (150 mil) SSOP
PSEL1
0
0
0
M
M
M
1
1
1
PSEL0
0
M
1
0
M
1
0
M
1
PCLK1
25.00
37.5
66.66
40.00
33.3334
20.00
20.00
20.00
50
Audio Clock (MHz)
ASEL
0
M
1
ACLK
49.152
24.576
14.318
PCLK2,3
50.00
75.00
133.33
80.00
66.6667
40.00
33.3334
66.6667
100
USB Clock (MHz)
USEL
0
M
1
UCLK
12
24
48
0 = connect directly to ground, 1 = connect directly
to VDD, M=leave unconnected (floating)
Pin Descriptions
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Name
USEL
X2
X1/ICLK
VDD
VDD
GND
UCLK
20M
ACLK
25M
OE
PCLK1
OFF/14.318M
GND
ASEL
VDD
PCLK3
PCLK2
PSEL0
PSEL1
Type
I
XO
XI
P
P
P
O
O
O
O
I
O
O
P
I
P
O
O
I
I
Description
UCLK Select pin. Determines frequency of USB clock per table above.
Crystal connection. Connect to parallel mode 25 MHz crystal. Leave open for clock.
Crystal connection. Connect to parallel mode 25 MHz crystal, or clock.
Connect to VDD. Must be same value as other VDD. Decouple with pin 6.
Connect to VDD. Must be same value as other VDD.
Connect to ground.
USB clock output per table above.
Fixed 20 MHz output for Ethernet.
AC97 Audio clock output per table above.
Fixed 25 MHz reference output for Fast Ethernet.
Output Enable. Tri-states all outputs when low.
PCLK output number 1 per table above.
14.31818 MHz clock output only when ASEL=VDD.
Connect to ground.
ACLK Select pin. Determines frequency of Audio clock per table above.
Connect to VDD. Must be same value as other VDD. Decouple with pin 14.
PCLK output number 3 per table above.
PCLK output number 2 per table above.
Processor Select pin #0. Determines frequencies on PCLKs 1-3 per table above.
Processor Select pin #1. Determines frequencies on PCLKs 1-3 per table above.
Key: I = Input; XO/XI = crystal connections; O = output; P = power supply connection
2
Revision 010301
Integrated Circuit Systems, Inc. • 525 Race Street • San Jose •CA•95126• (408) 295-9800tel • www.icst.com
MDS 650-21 A
PRELIMINARY INFORMATION
ICS650-21
System Peripheral Clock Source
Electrical Specifications
Parameter
Conditions
Minimum
Typical
Maximum
Units
7
VDD+0.5
70
260
150
V
V
C
C
C
5.5
V
V
V
V
V
V
mA
mA
mA
pF
ABSOLUTE MAXIMUM RATINGS (note 1)
Supply voltage, VDD
Inputs and Clock Outputs
Ambient Operating Temperature
Soldering Temperature
Storage temperature
Referenced to GND
Referenced to GND
-0.5
0
Max of 10 seconds
-65
DC CHARACTERISTICS (VDD = 3.3V or 5V unless noted)
Operating Voltage, VDD
Input High Voltage, VIH
Input Low Voltage, VIL
Output High Voltage, VOH
Output Low Voltage, VOL
Output High Voltage, VOH, VDD = 3.3 or 5V
Operating Supply Current, IDD, at 5V
Operating Supply Current, IDD, at 3.3V
Short Circuit Current, VDD = 3.3
Input Capacitance
3.0
2
Select inputs, OE
Select inputs, OE
VDD=3.3V, IOH=-8mA
2.4
VDD=3.3V, IOL=8mA
IOH=-8mA
VDD-0.4
No Load, note 2
No Load, note 2
Each output
Except X1
0.8
0.4
50
30
±50
5
AC CHARACTERISTICS (VDD = 3.3V or 5V unless noted)
Input Crystal or Clock Frequency
Output Clocks Accuracy (synthesis error)
Output Clock Rise Time
Output Clock Fall Time
Output Clock Duty Cycle, UCLCK
Output Clock Duty Cycle, PCLCK, ACLCK
One Sigma Jitter, except ACLK
One Sigma Jitter, ACLK
Absolute Clock Period Jitter PCLK, UCLK, 20M
Notes:
25.000
All clocks
0.8 to 2.0V
2.0 to 0.8V
At VDD/2
At VDD/2
40
45
- 500
50
50
75
120
1
1.5
1.5
60
55
500
MHz
ppm
ns
ns
%
%
ps
ps
ps
1. Stresses beyond those listed under Absolute Maximum Ratings could cause permanent damage to the device. Prolonged
exposure to levels above the operating limits but below the Absolute Maximums may affect device reliability.
2. With all clocks at highest frequencies.
External Components
The ICS650 requires a minimum number of external components for proper operation. Decoupling
capacitors of 0.1µF should be connected between VDD and GND (on pins 4 and 6, and pins 16 and 14),
as close to the chip as possible. A series termination resistor of 33Ω may be used for each clock output. The
25.000 MHz crystal must be connected as close to the chip as possible. The crystal should be a fundamental
mode, parallel resonant, 30ppm or better (to meet the Ethernet specs). Crystal capacitors should be
connected from pins X1 to ground and X2 to ground. The value of these capacitors is given by the
following equation, where CL is the crystal load capacitance: Crystal caps (pF) = (CL -12) x 2. So for a
crystal with 16pF load capacitance, two 8pF caps should be used. If a clock input is used, drive it into X1
and leave X2 unconnected.
3
Revision 010301
Integrated Circuit Systems, Inc. • 525 Race Street • San Jose •CA•95126• (408) 295-9800tel • www.icst.com
MDS 650-21 A
PRELIMINARY INFORMATION
ICS650-21
System Peripheral Clock Source
Package Outline and Package Dimensions
(For current dimensional specifications, see JEDEC Publication No. 95.)
20 pin SSOP
E1
INDEX
AREA
1
Symbol
A
A1
b
c
D
e
E
E1
L
E
2
Inches
Min
Max
0.053 0.069
0.004 0.010
0.008 0.012
0.007 0.010
0.337 0.344
.025 BSC
0.228 0.244
0.150 0.157
0.016 0.050
Millimeters
Min
Max
1.35
1.75
0.10
0.25
0.20
0.30
0.18
0.25
8.55
8.75
0.635 BSC
5.80
6.20
3.80
4.00
0.40
1.27
D
A1
A
c
e
b
L
Ordering Information
Part/Order Number
ICS650R-21
ICS650R-21T
ICS650R-21I
ICS650R-21IT
Marking
ICS650R-21
ICS650R-21
ICS650R-21I
ICS650R-21I
Package
20 pin SSOP
20 pin SSOP
20 pin SSOP
20 pin SSOP
Shipping
Tubes
Tape and Reel
Tubes
Tape and Reel
Temperature
0 to 70° C
0 to 70° C
-40 to 85° C
-40 to 85° C
While the information presented herein has been checked for both accuracy and reliability, Integrated Circuit Systems, Incorporated (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.
4
Revision 010301
Integrated Circuit Systems, Inc. • 525 Race Street • San Jose •CA•95126• (408) 295-9800tel • www.icst.com
MDS 650-21 A
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