ASM3P2854B_1 Datasheet, PDF (1/8 Pages) PulseCore Semiconductor – Custom Clock Generator for Fax System

August 2007
rev 0.3
Custom Clock Generator for Fax System
ASM3P2854B
Features
• Generates Custom Clocks for FAX system from
an inexpensive 24MHz Crystal
• 2x 66.66MHz low EMI (Spread Spectrum) clocks
for ASIC1 (System / DDR SDRAM)
• 1 x 48MHz for USB1.1 HOST
• 2 x 33.33MHz low EMI (Spread Spectrum)
clocks for System / DDR SDRAM of ASIC2 and
ASIC3
Product Description
ASM3P2854B is a part of the two chip custom clock
generator solution for NEC FAX system. Together with
ASM3P2855A, ASM3P2854B realizes all the seventeen
clocks required by the various components and
subsystems of the FAX system. It uses an inexpensive
24MHz crystal as the input to generate two 66.66MHz low
EMI (spread spectrum) clocks used by ASIC1 for system
/ DDR SDRAM, two 33.33MHz low EMI (spread
spectrum) clocks used by ASIC2 and ASIC3 for system /
DDR SDRAM, a 25MHz low EMI (Spread Spectrum)
clock used by ASIC1 for LCD, Serial port, and buzzer, a
Block Diagram
VDD
• 1x 25MHz low EMI (Spread Spectrum) clock for
LCD, Serial port, and buzzer of ASIC1
• 1x 12MHz for USB PHY (USB2.0)
• 1x Programmable clock for printer engine control
• One of the four programmable clock outputs
selection through two Select Pins
• Supply Voltage 3.3V +/- 0.3V
• Available in 16L TSSOP, Green package
• Commercial Temperature operation
48MHz clock used by USB1.1 HOST, and a 12MHz clock
used by USB PHY (USB2.0). One of the four
Programmable clock (PCLK) frequencies of
24.00448MHz, 21.33732MHz, 21.19962MHz and
20.40464MHz used for Printer Engine control is
selectable through two Select pins S1 and S2. The
accuracy of the synthesized programmable clocks is
within +/- 18ppm. The custom clock generator works with
a Supply Voltage for 3.3V. The device is available in a
16L TSSOP Green package, in commercial temperature
range. The output Clocks have an accuracy of ±50ppm.
VDD_FOUT
XIN / CLKIN
XOUT
Crystal
(24 MHz)
2
66.6MHz SSCLK
PLL
2
33.3MHz SSCLK
25MHz SSCLK
48MHz
PLL
12MHz
PLL
S1
S2
PCLK
GND
GND_FOUT
PulseCore Semiconductor Corporation
1715 S. Bascom Ave Suite 200 Campbell, CA 95008 • Tel: [phone] • Fax: [phone]
www.pulsecoresemi.com
Notice: The information in this document is subject to change without notice.