PCS3P25811 and PCS3P25812 and PCS3P25814
Spread Spectrum Clock
• Generates a 1x (PCS3P25811), 2x (PCS3P25812)
and 4x(PCS3P25814) low EMI spread spectrum
clock of the input frequency
• Provides up to 15dB of EMI suppression
• Input Frequency: 4MHz - 32MHz
• Output Frequency:
PCS3P25811: 4MHz - 32MHz
PCS3P25812: 8MHz - 64MHz
PCS3P25814: 16MHz - 128MHz
• Selectable spread options: Down Spread and Center
• Low Power Dissipation:
3.3V: 20mW (typ) @ 6MHz
3.3V: 24mW (typ) @ 12MHz
3.3V: 30mW (typ) @ 24MHz
• Low inherent Cycle-to-Cycle Jitter
• Supply Voltage: 2.8V to 3.6V
• LVCMOS Input and output
• Functional and Pinout compatible to Cypress
CY25811, CY25812 and CY25814
• 8-pin SOIC, and 8L 2mmX2mm WDFN (TDFN)
The PCS3P25811/12/14 devices are versatile spread
spectrum frequency modulators designed specifically for
a wide range of input clock frequencies from 4MHz to
The PCS3P25811/12/14 reduce electromagnetic
interference (EMI) at the clock source, allowing system
wide reduction of EMI of down stream clock and data
dependent signals. It allows significant system cost
savings by reducing the number of circuit board layers,
ferrite beads, shielding, and other passive components
that are traditionally required to pass EMI regulations.
The PCS3P25811/12/14 can generate an EMI reduced
clock from crystal, ceramic resonator, or system clock.
The PCS3P25811/12/14 modulate the output of a single
PLL in order to “spread” the bandwidth of a synthesized
cock, and more importantly, decreases the peak
amplitudes of its harmonics. This results in significantly
lower system EMI compared to the typical narrow band
signal produced by oscillators and most frequency
generators. Lowering EMI by increasing a signal’s
bandwidth is called ‘spread spectrum clock generation.’
The PCS3P25811/12/14 use the most efficient and
optimized modulation profile approved by the FCC and is
implemented in a proprietary all-digital method.
The PCS3P25811/12/14 have 2 pins S0 and S1 to control
the selection of Center Spread, Down Spread and No-
Spread functions. Additionally there is a 3 level logic
contol FSEL, for selecting one of the three different
frequency ranges within the operating frequency range.
Refer Input/Output Frequency Range Selection Table.
The PCS3P25811/12/14 operate from a 2.8V to 3.6V
supply and are available in 8 pin SOIC, and 8L
2mmX2mm WDFN packages.
The PCS3P25811/12/14 are targeted towards EMI
management in applications such as LCD Panels, MFPs,
Digital copiers, Networking, PC peripheral devices,
consumer electronics, and embedded controller systems.
©2010 SCILLC. All rights reserved.
JANUARY 2010 – Rev. 1
Publication Order Number: