W181 Datasheet, PDF (1/9 Pages) Cypress Semiconductor – Peak Reducing EMI Solution

W181
Features
• Cypress PREMIS™ family offering
• Generates an EMI optimized clocking signal at the out-
put
• Selectable input to output frequency
• Single 1.25% or 3.75% down or center spread output
• Integrated loop filter components
• Operates with a 3.3V or 5V supply
• Low power CMOS design
• Available in 8-pin SOIC (Small Outline Integrated Cir-
cuit) or 14-pin TSSOP (Thin Shrink Small Outline Pack-
age select options only)
Key Specifications
Supply Voltages: ........................................... V_DD = 3.3V±5%
or V_DD = 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.)
Simplified Block Diagram
3.3 or 5.0V
XTAL
Input
40 MHz
Max.
X1
X2
W181
Spread Spectrum
Output
(EMI suppressed)
3.3 or 5.0V
Oscillator or
Reference Input
W181
Spread Spectrum
Output
(EMI suppressed)
Peak Reducing EMI Solution
Table 1. Modulation Width Selection
SS%
0
1
W181-01, 02, 03
Output
F_in ≥ F_out ≥ F_in –
1.25%
F_in ≥ F_out ≥ F_in –
3.75%
W181-51, 52, 53
Output
F_in + 0.625% ≥ F_in≥
– 0.625%
F_in + 1.875% ≥ F_in≥
–1.875%
Table 2. Frequency Range Selection
W181 Option#
FS2 FS1
-01, 51
(MHz)
-02, 52
(MHz)
-03, 53
(MHz)
0
0 28 ≤ F_IN ≤ 38 28 ≤ F_IN ≤ 38
N/A
0
1 38 ≤ F_IN ≤ 48 38 ≤ F_IN ≤ 48
N/A
1
0 46 ≤ F_IN ≤ 60
N/A
46 ≤ F_IN ≤ 60
1
1 58 ≤ F_IN ≤ 75
N/A
58 ≤ F_IN ≤ 75
Pin Configurations
SOIC
CLKIN or X1 1
NC or X2 2
GND 3
SS% 4
8 FS2
7 FS1
6 VDD
5 CLKOUT
CLKIN or X1 1
NC or X2 2
GND 3
SS% 4
8 SSON#
7 FS1
6 VDD
5 CLKOUT
TSSOP
FS2 1
CLKIN or X1 2
NC or X2 3
GND 4
NC 5
SS% 6
NC 7
14 _NC
13 _NC
12 FS1
11 NC
10 VDD
9 NC
8 CLKOUT
PREMIS is a trademark of Cypress Semiconductor Corporation.
Cypress Semiconductor Corporation • 3901 North First Street • San Jose • CA 95134 • 408-943-2600
July 21, 2000, rev. *B