CY22K7 Datasheet, PDF (1/11 Pages) Cypress Semiconductor – 133-MHz Spread Spectrum Clock Generator For Use With the AMD-K7 Processor and AMD-750 Chipset

CY22K7
133-MHz Spread Spectrum Clock Generator For Use With
the AMD-K7^® Processor and AMD-750 Chipset
Features
Benefits
• Multiple output clocks running at different frequencies
— Three open-drain differential CPU outputs running up
to 133 MHz
— Eight 3.3V synchronous PCI clocks (one free running)
— Two 3.3V AGP clocks at 2xPCI
— One dedicated 3.3V USB clock at 48 MHz
— One 3.3V USB/IO clock at 48 MHz or 24 MHz, selectable
via power-on latch input
— One 3.3V SDRAM clock output running at the CPU fre-
quency
— Two 3.3V Reference clocks at 14.318 MHz
Main clock generator for PC motherboard designs using the
AMD-K7 processor and AMD-750 Chipset
— Supports up to two CPUs and chipset
— Support for 4 PCI slots and chipset
— Supports designs using AGP
— Supports designs using USB
— Allows for one additional USB output or support for I/O
chip from various vendors
— Supports SDRAM memory architecture with external
PLL buffer
— Supports ISA slots and I/O chip
• Spread Spectrum clocking
— 33 kHz modulation frequency
— −0.6% downspread margin
EMI reduction
• Dedicated inputs for various functions
— PCI_STOP
— CPU_STOP
— PWR_DWN
— SPREAD
— TEST
— USB/IO
— FS [0:1]
• I²C interface
Provides system design flexibility and power management
— Stops all PCI clocks (except PCICLK_F0) when LOW
— Stops all CPU clocks when LOW
— Power is removed from internal logic when LOW
— Activates Spread Spectrum for lower EMI
— Used to enter Test Mode
— Selects USB or SuperIO Clock
— Power-on latched inputs for frequency select options
Dynamic control of output clock signals via SMBus
• 48-Pin SSOP package
Industry-standard package provides cost and space savings
Logic Block Diagram
XTALIN
XTALOUT
CPU_STOP
SPREAD
FSO
FS1
TEST
SCLK
SDATA
PCI_STOP
PWR_DWN
USB/IO
14.318 MHz
Xtal
Oscillator
CONTROL
LOGIC
CPU PLL
STOP
LOGIC
DIVIDER
2X
STOP
LOGIC
SYSTEM PLL
/2
LATCH
REF [0:1]
SDRAM_OUT
CPUCLKT [0:2]
CPUCLKC [0:2]
AGPCLK [0:1]
PCICLK [0:6]
PCICLK_F
USB0
USB/IO
Cypress Semiconductor Corporation • 3901 North First Street • San Jose • CA 95134 • 408-943-2600
August 9, 1999