CY2907
Document #: 38-07137 Rev. *A
Page 2 of 11
Functional Description
The CY2907 is a general purpose clock generator designed
for use in a wide variety of applications—from graphics to PC
peripherals to disk drives. It generates selectable system clock
frequencies from a single reference input (crystal or reference
clock). The CY2907 is configured with an EPROM array,
similar to the other devices in the Cypress EPROM Program-
mable Clock family, making it easy to customize for any appli-
cation. Furthermore, the CY2907 is compatible with all
industry-standard 9107 and 9108 clock synthesizers.
Device Programming
Two versions of the CY2907 are available - Field Program-
mable and Factory Programmable. Field programmable
devices must be programmed before being installed in an
application.
They
are
one-time-programmable
(OTP).
Customers can program small quantities in-house using the
Cypress CY3670 programmer. Production quantities are
available through Cypress’s value-added distribution partners,
or by using third party programmers from BP Microsystems,
Hi-Lo Systems, and others.
For high-volume orders, devices can be factory programmed
by Cypress. All requests must be submitted to the local
Cypress Field Application Engineer (FAE) or sales represen-
tative. Once the request has been processed, you will receive
a new part number, samples, and a data sheet with the
programmed values. This part number will be used for
additional sample requests and production orders.
CyberClocks™ Software
CyberClocks is an easy-to-use software application that
allows the user to configure any one of the EPROM Program-
mable Clocks offered by Cypress. You may specify the input
frequency, PLL and output frequencies, and different
functional options. Note the output frequency ranges in this
data sheet when specifying them in CyberClocks to make sure
that you stay within the limits. Once a configuration is estab-
lished, you can print the configuration and save programming
files in ENT and JED formats.
CyberClocks runs on PCs running the Windows™ operating
system, and is available for free download on the Cypress
Semiconductor website at www.cypress.com.
Within the CyberClocks application, the CY2907 is found in the
CyClocks™ section. Note that the stand-alone CyberClocks
software should not be confused with the CyberClocks Online
software, which is a web-based application that is used to
configure other programmable clock devices.
Cypress CY3670 Programming Kit
Cypress’s CY3670 is a portable programmer that connects to
a PC serial port and allow users of CyClocks software to
quickly and easily program any of the CY2291F, CY2292F,
CY2071AF, and CY2907F devices. An adapter is also required
and is ordered separately. The CY3097 is the adapter for the
CY2907F8. For the CY2907F14, order adapter CY3098.
Notes
1. For best accuracy, use a parallel resonant crystal, CLOAD ≈ 17 pF.
2. Float XTALOUT pin if XTALIN is driven by reference clock (as opposed to crystal).
Pin Summary
Name
Pin Number
Description
14-Pin SOIC
8-Pin SOIC
S1
1
5
Frequency Select (CLKA) (Internal pull up resistor to VDD)
S2
2
NA
Frequency Select (CLKA) (Internal pull up resistor to VDD)
S3
3
NA
Frequency Select (CLKA) (Internal pull up resistor to VDD)
VSS
4
2
Ground
VSS
5
NA
Ground
PD
6
NA
Power Down (Active LOW) (Internal pull up resistor to VDD)
XTALIN[1]
7
3
Reference Crystal Input
XTALOUT[1, 2]
8
4
Reference Crystal Feedback
OER
9
NA
REFCLK Output Enable (Active HIGH) (Internal pull up resistor to VDD)
OEA
10
NA
CLKA Output Enable (Active HIGH) (Internal pull up resistor to VDD)
CLKA
11
6
Clock Output
VDD
12
7
Voltage Supply
REFCLK
13
8
Reference Clock Output (Default, can be driven by PLL if desired)
S0
14
1
Frequency Select (CLKA) (Internal pull up resistor to VDD)
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