IMIC9530CT Cypress Semiconductor Corp, IMIC9530CT Datasheet - Page 6

• Manufacturer Part Number: IMIC9530CT
• Manufacturer: Cypress Semiconductor Corp

Specifications of IMIC9530CT

• Function: Clock Generator
• Operating Temperature (max): 70C
• Operating Temperature (min): 0C
• Package Type: TSSOP
• Pin Count: 48
• Mounting: Surface Mount
• Lead Free Status / Rohs Status: Not Compliant

Document #: 38-07033 Rev. *C
As an example and using this formula for this data sheet’s
device, a design that has no discrete loading capacitors
(C
capacitance (C
calculate as follows.
Therefore, to obtain output frequencies that are as close to this
data sheets specified values as possible, in this design
example, you should specify a parallel cut crystal that is
designed to work into a load of 20 pF.
Table 7. Spectrum Spreading Selection Table
Note:
7. When SSCG is enabled, the device will down spread the clock over a range that is 1% of its resting frequency. This means that for a 100-MHz output clock
C
DISC
L
frequency will sweep through a spectral range from 99 to 100 MHz.
Output Clock Frequency
=
=
=
=
) and each of the crystal device PCB traces has a
100.0 MHz (XIN*3)
133.3 MHz (XIN*4)
66.6 MHz (XIN*2)
(4 pF + 36 pF + 0 pF) x (4 pF + 36 pF + 0 pF)
(4 pF + 36 pF + 0 pF) x (4 pF + 36 pF + 0 pF)
20 pF
1600
33.3 MHz (XIN)
40 x 40
40 x 40
80
PCB
S p r e a d o n
) to ground of 4 pF (typical value) would
C
C
XINPCB
XOUTPCB
C
C
XINDISC
XOUTDISC
C e n t e r F r e q u e n c y ,
S p r e a d o n
SMBus Byte 0 Bit 5 = 0
1.0% (–1.0% + 0%)
1.0% (–1.0% + 0%)
1.0% (–1.0% + 0%)
1.0% (–1.0% + 0%)
Clock Generator
XOUT
XIN
[7]
Figure 1. Spread Spectrum
C
C
XINFTG
XOUTFTG
% of Frequency Spreading
Spread Spectrum Clocking
Down Spread Description
Spread Spectrum is a modulation technique for distributing
clock period over a certain bandwidth (called Spread
Bandwidth). This technique allows the distribution of the
undesirable electromagnetic energy (EMI) over a wide range
of frequencies therefore reducing the average radiated energy
present at any frequency over a given time period. As the
spread is specified as a percentage of the resting (non-spread)
frequency value, it is effective at the fundamental and, to a
greater extent, at all it's harmonics.
In this device, Spread Spectrum is enabled externally through
pin 27 (SSCG#) or internally via SMBus Byte 0 Bit 0 and 6.
Spread spectrum is enabled externally when the SSCG# pin
is low. This pin has an internal device pull up resistor, which
causes its state to default to a high (Spread Spectrum
disabled) unless externally forced to a low. It may also be
enabled by programming SMBus Byte 0 Bit 0 LOW (to enable
SMBus control of the function) and then programming SMBus
Byte 0 Bit 6 LOW to set the feature active.
SMBus Byte 0 Bit 5 = 1
0.5% (–0.5% + 0%)
0.5% (–0.5% + 0%)
0.5% (–0.5% + 0%)
0.5% (–0.5% + 0%)
C e n t e r F r e q u e n c y ,
S p r e a d o f f
S p r e a d o f f
Down Spread
Down Spread
Down Spread
Down Spread
Mode
Page 6 of 11
C9530
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