PRELIMINARY
CY2XF33
Document Number: 001-53148 Rev. *B
Page 2 of 7
Functional Description
The FS0 and FS1 pins select between four different output
frequencies, as shown in Table 2. Frequency margining is a
common application for this feature. One frequency is used for
the standard operating mode of the device, while the other
frequencies are available for margin testing, either during
product development or in system manufacturing test.
When changing the output frequency, the frequency transition is
not guaranteed to be smooth. There can be frequency excur-
sions beyond the start frequency and the new frequency.
Glitches and runt pulses are possible, and time must be allowed
for the PLL to relock.
Programming Description
The CY2XF33 is a programmable device. Before being used in
an application, it must be programmed with the output
frequencies and other variables described in a later section. Two
different device types are available, each with its own
programming flow. They are described in the following sections.
Field Programmable CY2XF33F
Field programmable devices are shipped unprogrammed and
must be programmed before being installed on a printed circuit
board (PCB). Customers use CyberClocks™ Online Software to
specify the device configuration and generate a JEDEC
(extension .jed) programming file. Programming of samples and
prototype quantities is available using a Cypress programmer.
Third party vendors manufacture programmers for small to large
volume applications. Cypress’s value added distribution partners
also provide programming services. Field programmable
devices are designated with an “F” in the part number. They are
intended for quick prototyping and inventory reduction. The
CY2XF33 is one time programmable (OTP).
The software is located at www.cyberclocksonline.com.
Factory Configured CY2XF33
For customers wanting ready-to-use devices, the CY2XF33 is
available with no field programming required. All requests are
submitted to the local Cypress Field Application Engineer (FAE)
or sales representative. After the request is processed, the user
receives a new part number, samples, and data sheet with the
programmed values. This part number is used for additional
sample requests and production orders.
Programming Variables
Output Frequencies
The CY2XF33 is programmed with up to four independent output
frequencies, which are then selected using the FS0 and FS1
pins. The device can synthesize frequencies to a resolution of 1
part per million (ppm), but the actual accuracy of the output
frequency is limited by the accuracy of the integrated reference
crystal.
The CY2XF33 has an output frequency range of 50 MHz to
690 MHz, but the range is not continuous. The CY2XF33 cannot
generate frequencies in the ranges of 521 MHz to 529 MHz and
596 MHz to 617 MHz.
Industrial Versus Commercial Device Performance
Industrial and Commercial devices have different internal
crystals. This has a potentially significant impact on performance
levels for applications requiring the lowest possible phase noise.
CyberClocks Online Software displays expected performance
for both options.
Phase Noise Versus Jitter Performance
In most cases, the device configuration for optimal phase noise
performance is different from the device configuration for optimal
cycle to cycle or period jitter. CyberClocks Online Software
includes algorithms to optimize performance for either
parameter.
Table 2. Frequency Select
FS1
FS0
Output Frequency
0
0
Frequency 0
0
1
Frequency 1
1
0
Frequency 2
1
1
Frequency 3
Table 3. Device Programming Variables
Variable
Output Frequency 0 (Power on default)
Output Frequency 1
Output Frequency 2
Output Frequency 3
Optimization (phase noise or jitter)
Temperature range (Commercial or Industrial)
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