W181-01GT Datasheet, PDF (6/9 Pages) Cypress Semiconductor – Peak-Reducing EMI Solution

W181
AC Electrical Characteristics: T_A = 0°C to +70°C, V_DD = 3.3V ±5% or 5V±10%
Parameter
Description
Test Condition
Min.
Typ.
f_IN
f_OUT
t_R
t_F
t_OD
t_ID
t_JCYC
Input Frequency
Input Clock
28
Output Frequency
Spread Off
28
Output Rise Time
V_DD, 15-pF load 0.8V–2.4V
2
Output Fall Time
V_DD, 15-pF load 2.4V–0.8V
2
Output Duty Cycle
15-pF load
40
Input Duty Cycle
40
Jitter, Cycle-to-Cycle
250
Harmonic Reduction
f_out = 40 MHz, third harmonic
8
measured, reference board,
15-pF load
Max.
75
75
5
5
60
60
300
Unit
MHz
MHz
ns
ns
%
%
ps
dB
CLKOUT Frequency Offset (Shift)^[4,5]: T_A = 0°C to +70°C, V_DD = 3.3V ±5% or 5V±10% (For only W181-02, -02 and -03 products)
Parameter
Description
Frequency Range (MHz)
Min.
Typ.
Max.
Unit
FOFFSET-1
FOFFSET-2
FOFFSET-3
FOFFSET-4
Frequency Offset (Shift)
Frequency Offset (Shift)
Frequency Offset (Shift)
Frequency Offset (Shift)
FS2=0, FS1=0, 28≤F_IN≤38
FS2=0, FS1=1, 38≤F_IN≤48
FS2=1, FS1=0, 46≤F_IN≤60
FS2=1, FS1=1, 58≤F_IN≤75
–0.8
–1.0
–1.2
%
–1.1
–1.4
–1.7
%
–0.2
–0.5
–0.8
%
–0.8
–1.0
–1.2
%
Application Information
Recommended Circuit Configuration
For optimum performance in system applications the power
supply decoupling scheme shown in Figure 4 should be used.
V_DD decoupling is important to both reduce phase jitter and
EMI radiation. The 0.1-µF decoupling capacitor should be
placed as close to the V_DD pin as possible, otherwise the
increased trace inductance will negate its decoupling
capability. The 10-µF decoupling capacitor shown should be a
tantalum type. For further EMI protection, the V_DD connection
can be made via a ferrite bead, as shown.
Recommended Board Layout
Figure 5 shows a recommended 2-layer board layout.
Reference Input
1
NC ₂
GND ₃
4
8
7
6
5
R1
Clock
Output
C1
0.1 µF
3.3 or 5V System Supply
FB
C2
10-µF Tantalum
Figure 4. Recommended Circuit Configuration
Notes:
4. The frequency offset (shift) is given with respect to ideal peak value which is the same as input reference frequency in the case of down spread only for W180-01,-02
and -03 products.
5. There is no offset (shift) for center spread for W180-51,-52 and -53 products.
Document #: 38-07152 Rev. *D
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