Full Feature Peak Reducing EMI Solution
W183
Cypress Semiconductor Corporation
•
3901 North First Street
•
San Jose
•
CA 95134
•
408-943-2600
Document #: 38-07158 Rev. *A
Revised September 25, 2001
Features
• Cypress PREMIS™ family offering
• Generates an EMI optimized clocking signal at the out-
put
• Selectable output frequency range
• Single 1.25%, 3.75% down or center spread output
• Integrated loop filter components
• Operates with a 3.3 or 5V supply
• Low power CMOS design
• Available in 14-pin SOIC (Small Outline Integrated
Circuit)
Key Specifications
Supply Voltages: ...........................................VDD = 3.3V±5%
or VDD = 5V±10%
Frequency Range: ............................ 28 MHz
≤ F
in ≤ 75 MHz
Crystal Reference Range:................. 28 MHz
≤ F
in ≤ 40 MHz
Cycle to Cycle Jitter: ....................................... 300 ps (max.)
Selectable Spread Percentage: ....................1.25% or 3.75%
Output Duty Cycle: ............................... 40/60% (worst case)
Output Rise and Fall Time: .................................. 5 ns (max.)
Table 1. Modulation Width Selection
SS%
W183
Output
W183-5
Output
0Fin ≥ Fout ≥ Fin –
1.25%
Fin + 0.625% ≥ Fin≥
– 0.625%
1Fin ≥ Fout ≥ Fin –
3.75%
Fin + 1.875% ≥ Fin≥
–1.875%
Table 2. Frequency Range Selection
FS2
FS1
Frequency Range
00
28 MHz
≤ F
IN ≤ 38 MHz
01
38 MHz
≤ F
IN ≤ 48 MHz
10
46 MHz
≤ F
IN ≤ 60 MHz
11
58 MHz
≤ F
IN ≤ 75 MHz
PREMIS is a trademark of Cypress Semiconductor Corporation.
Simplified Block Diagram
Pin Configuration
SOIC
14
13
12
11
1
2
3
4
FS2
CLKIN or X1
NC or X2
GND
REFOUT
OE#
SSON#
Reset
5
6
7
8
9
10
VDD
VDD
CLKOUT
GND
SS%
FS1
Spread Spectrum
W183
(EMI suppressed)
3.3V or 5.0V
Oscillator or
Spread Spectrum
W183
(EMI suppressed)
3.3V or 5.0V
XTAL
X1
X2
Reference Input
Input
Output
Output
40 MHz
Max
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