CY22800
Document #: 001-07704 Rev. *A
Page 2 of 10
General Description
The CY22800 is a multi-function clock generator that supports
various applications in consumer and communications
markets. The device uses the Cypress proprietary PLL along
with Spread Spectrum and VCXO technology to make it one of
the most versatile clock synthesizers in the marketplace. The
CY22800 is a field-programmable synthesizer that can be
programmed using an easy-to-use programmer dongle,
CY36800, with one of many predefined configuration files for
fast sample generation of prototype builds. The CY22800 is a
reprogrammable device that can be programmed up to 100
times. The latest configurations available for this device are
summarized in Table 1.
Spread Spectrum Clock Generation (SSCG)
The CY22800 can generate Spread Spectrum Clocks (SSCG)
to reduce EMI found in today’s high-speed digital electronic
systems.
The device uses proprietary Spread Spectrum Clock (SSC)
technology to synthesize and modulate the frequency of the
input clock. By modulating the frequency of the clock, the
measured EMI at the fundamental and harmonic frequencies
is greatly reduced. This reduction in radiated energy can
significantly reduce the cost of complying with regulatory
agency (EMC) requirements and improve time to market
without degrading system performance.
The CY22800 uses a preprogrammed configuration of
memory arrays to synthesize output frequency and offers eight
different spread percentages (refer to Table 1 – Code numbers
-015 to -022), and an additional option to turn the spread on
and off.
For the above-mentioned configurations, the modulation
frequency varies with the reference frequency as follows:
VCXO
One of the key components of the CY22800 device is the
VCXO. The VCXO is used to “pull” the reference crystal higher
or lower in order to lock the system frequency to an external
source. This is ideal for applications where the output
frequency needs to track along with an external reference
frequency that is constantly shifting.
A special pullable crystal must be used in order to have
adequate VCXO pull range. Pullable Crystal specifications are
included in this data sheet.
VCXO Profile
Figure 1 shows an example of what a VCXO profile looks like.
The analog voltage input is on the X-axis and the PPM range
is on the Y-axis. An increase in the VCXO input voltage results
in a corresponding increase in the output frequency. This has
the effect of moving the PPM from a negative to positive offset.
Figure 1. VCXO Profile
1000
mod
ref
f
f
=
-200
-150
-100
-50
0
50
100
150
200
00.5
11.5
22.5
33.5
VCXOinput [V]
Table 1. CY22800 Configurations
Code #
Code name
Input Freq. (MHz)
Output Freq. (MHz)
SS
VCXO
Commercial Temperature Range
CY22800-001A X2 Multiplier
CLKIN: 0.5–100
XTAL: 8–30
CLKA: 1–200 or REFOUT
N
N
CY22800-002A X3 Multiplier
CLKIN: 0.5–66.66
XTAL: 8–30
CLKA: 1.5–200 or REFOUT
N
N
CY22800-003A X4 Multiplier
CLKIN: 0.5–50
XTAL: 8–30
CLKA: 2–200 or REFOUT
N
N
CY22800-004A X5 Multiplier
CLKIN: 0.5–40
XTAL: 8–30
CLKA: 2.5–200 or REFOUT
N
N
CY22800-005A X6 Multiplier
CLKIN: 0.5–33.33
XTAL: 8–30
CLKA: 3–200
CLKB: REFOUT
NN
CY22800-006A X8 Multiplier
CLKIN: 0.5–25
XTAL: 8–25
CLKA: 4–200
CLKB: REFOUT
NN
CY22800-007A Clock multiplier for consumer & communication applications
14.318[2]
CLKA: 33.33, 66.66, 50, 75, 80, 100, 133.33
See D/S
NN
CY22800-008A Clock multiplier for consumer & communication applications
14.318[2]
CLKA: 12, 24, 48, 60, 62.5, 106.25, 125
See D/S
NN
Note
2. Fixed CLKIN/Xtal frequency. Refer to the one page data sheet corresponding to the Code # for detailed input and output ranges.
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