CY2273A Cypress Semiconductor, CY2273A Datasheet
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CY2273A
Manufacturer Part Number
CY2273A
Description
K6 Clock Synthesizer/Driver
Manufacturer
Cypress Semiconductor
Datasheet
1.CY2273A.pdf
(14 pages)
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
CY2273APVC-1
Manufacturer:
CY
Quantity:
24
Part Number:
CY2273APVC-1
Manufacturer:
CYP
Quantity:
20 000
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Part Number:
CY2273APVC-3
Manufacturer:
CY
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25
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Part Number:
CY2273APVC-4
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Quantity:
5
Features
Functional Description
The CY2273A is a clock synthesizer/driver for a Pentium, Pen-
tium II, Cyrix, or AMD processor-based PC using Intel’s
82430TX, 82440LX, ALI Aladdin IV or Aladdin IV+ chipsets.
The CY2273A-1 outputs four CPU clocks at 2.5V or 3.3V with
up to 83.3MHz operation. There are seven PCI clocks, running
at 30 and 33.3MHz. One of the PCI clocks is free-running.
Additionally, the part outputs up to twelve 3.3V SDRAM clocks,
one 3.3V USB clock at 48 MHz, and one 3.3V reference clock
at 14.318 MHz. The CY2273A-2 is similar, except that
PCICLK4 and PCICLK5 are now AGP clocks. The CY2273A-3
is more suited to Pentium II systems, as it outputs one 2.5V
IOAPIC clock. Finally, the CY2273A-4 is similar to the
CY2273A-1 except that is supports 0-ns CPU-PCI delay.
Cypress Semiconductor Corporation
• Mixed 2.5V and 3.3V operation
• Complete clock solution for Pentium®, Pentium® II,
• I
• Factory-EPROM programmable output drive and slew
• Factory-EPROM programmable CPU clock frequencies
• Power-down, CPU stop and PCI stop pins
• Available in space-saving 48-pin SSOP package
Intel and Pentium are registered trademarks of Intel Corporation. I
Logic Block Diagram
Pentium®/II, 6x86, K6 Clock Synthesizer/Driver for Desktop PCs
Cyrix, and AMD processor-based motherboards
rate for EMI customization
for custom configurations
— Four CPU clocks at 2.5V or 3.3V
— Up to twelve 3.3V SDRAM clocks
— Seven synchronous PCI clocks, one free-running
— One 3.3V 48 MHz USB clock
— One 2.5V IOAPIC clock (-3 option only)
— Two AGP clocks at 60 or 66.6MHz (-2 option only)
— One 3.3V Ref. clock at 14.318 MHz
2
with Intel 82430TX, 82440LX or ALI IV/IV+, AGP and 3 DIMMs
C™ Serial Configuration Interface
XTALOUT
XTALIN
MODE
SDATA
CY2273A-1,-2,-4 only
SEL1
SEL0
SCLK
14.318
OSC.
MHz
INTERFACE
CONTROL
SERIAL
LOGIC
SYS PLL
EPROM
CPU
PLL
www.DataSheet4U.com
Delay (-1,-2 option)
/1 or /1.25
/1 or /2
•
3901 North First Street
STOP
LOGIC
STOP
LOGIC
2
C is a trademark of Philips Corporation.
CY2273A-3 only
The CY2273A possesses power-down, CPU stop, and PCI
stop pins for power management control. These inputs are
multiplexed with SDRAM clock outputs, and are selected when
the MODE pin is driven low. Additionally, the signals are syn-
chronized on-chip, and ensure glitch-free transitions on the
outputs. When the CPU_STOP input is asserted, the CPU
clock outputs are driven LOW. When the PCI_STOP input is
asserted, the PCI clock outputs (except the free-running PCI
clock) are driven LOW. When the PWR_DWN pin is asserted,
the reference oscillator and PLLs are shut down, and all out-
puts are driven LOW.
The CY2273A outputs are designed for low EMI emissions.
Controlled rise and fall times, unique output driver circuits and
factory-EPROM programmable output drive and slew-rate en-
able optimal configurations for EMI control.
CY2273A Selector Guide
Note:
1.
CPU (60, 66.6, 75,
83.3 MHz)
CPU (60, 66.6 MHz)
SDRAM
PCI (30, 33.3MHz)
USB/IR (48MHz)
AGP (60 or 66MHz)
IOAPIC (14.318MHz)
Ref (14.318MHz)
CPU-PCI delay
Clocks Outputs
One free-running PCI clock.
PCICLK_F
USBCLK (48 MHz)
IOAPIC
V
REF0 (14.318 MHz)
CPUCLK [0-3]
V
SDRAM5/PWR_DWN
SDRAM [0-4],[8-11]
SDRAM6/CPU_STOP
SDRAM7/PCI_STOP
AGP [0,1]
PCI [0-5], PCI [0-3]
DDQ2
DDCPU
•
CY2273A-2 only
San Jose
1–5.5 ns 1–5.5 ns
•
9/12
7
-1
4
--
--
--
1
1
[1]
CA 95134
9/12
5
-2
--
--
4
1
2
1
[1]
•
October 12, 1998
CY2273A
9/12
408-943-2600
0 ns
7
-3
--
4
1
--
1
1
[1]
9/12
0 ns
7
-4
--
--
--
4
1
1
[1]