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參數(shù)資料
| 型號(hào)： | CY2278A |
| 廠商： | Cypress Semiconductor Corp. |
| 英文描述： | PentiumII Clock Synthesizer/Driver for Mobile PCs with Intel 82430TX and No SDRAM(帶英特爾82430TX和2個(gè)DIMM 或3個(gè)SO-DIMM 的應(yīng)用于移動(dòng)PC機(jī)的奔騰II6x86, K6 時(shí)鐘合成器/驅(qū)動(dòng)器) |
| 中文描述： | PentiumII時(shí)鐘合成器/與英特爾82430TX和無(wú)內(nèi)存（帶英特爾82430TX內(nèi)存和2個(gè)或3個(gè)SO - DIMM插槽的應(yīng)用于移動(dòng)電腦機(jī)的奔騰II6x86，K6時(shí)鐘合成器便攜式電腦驅(qū)動(dòng)器/驅(qū)動(dòng)器） |
| 文件頁(yè)數(shù)： | 1/11頁(yè) |
| 文件大?。?/td> | 153K |
| 代理商： | CY2278A |
Pentium
/II Clock Synthesizer/Driver for Mobile PCs
with Intel 82430TX and No SDRAM
CY2278A
Cypress Semiconductor Corporation
3901 North First Street
San Jose
CA 95134
408-943-2600
October 14, 1999
Features
Mixed 2.5V and 3.3V operation
Complete clock solution to meet requirements of mo-
bile Pentium and Pentium II motherboards
—Seven CPU clock outputs (three at 3.3V, and four at
2.5V or 3.3V) with eight selectable clock frequencies.
—Ten 3.3V synchronous PCI clock outputs
—Two 3.3V USB/IR clocks at 48 MHz
—One Keyboard clock at 8 MHz
—One 2.5V IOAPIC clock at 14.318 MHz
—Two 3.3V Ref. clocks at 14.318 MHz
Dedicated power management for portable systems
—Separate output enable pins for CPU, PCI, and
USB/IR clock sets
—Free-running PCI and CPU clocks (see options)
Factory-EPROM programmable output drive and slew
rate for EMI customization
Custom configuration with factory-EPROM program-
mable CPU, PCI, and USB/IR frequencies.
Low skew and low jitter outputs
Available in space-saving 48-pin TSSOP package
Functional Description
The CY2278A is a Clock Synthesizer/Driver chip for Pentium,
or Pentium II portable PCs designed with the 82430TX or sim-
ilar core-logic chipsets. There are four options available as
shown in the selector guide.
The CY2278A outputs seven CPU clocks, three of which run
at 3.3V and four run at either 2.5V or 3.3V, depending on the
voltage applied on pin 42. There are ten PCI clocks, running
at one half the CPU clock frequency. Free-running PCI and
CPU clocks are available as options shown in the selector
guide. Additionally, the part outputs two 3.3V USB/IR clocks at
48 MHz, one Keyboard clock at 8 MHz, one 2.5V IOAPIC clock
at 14.318 MHz, and two 3.3V reference clocks at 14.318 MHz.
The CY2278 family contains several features for output flexi-
bility and power control. The CPU, PCI, USB and IR clock fre-
quencies are all factory EPROM-programmable. Three hard-
ware select inputs support eight CPU clock frequencies from
20 – 75 MHz. Additionally, each of the CPU, PCI, and USB/IR
clock sets can be turned on or off with a dedicated enable input
pin for power management.
The CY2278A 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.
CY2278A Selector Guide
Notes:
1.
2.
2.5–3.3V Driver
One free-running CPU clock.
Two free-running PCI clocks.
Clock Outputs
CPU@3.3V
CPU@2.5/3.3V
PCI (CPU/2MHz)
USB/IR (48MHz)
KB (8MHz)
IOAPIC (14.318 MHz)
Ref (14.318MHz)
CPU-PCI delay
-1L
3
4
[1]
10
[2]
2
1
2
2
0 ns
-2L
3
4
10
2
1
2
2
0 ns
-3L
3
4
10
[2]
2
1
2
2
1–5 ns
-4L
3
4
10
[2]
2
1
2
2
0 ns
Intel and Pentium are registered trademarks of Intel Corporation.
EPROM
Logic Block Diagram
X
OUT
X
IN
IOAPIC
OSC.
CLK8MHz
SEL2
SEL1
SEL0
XCPUCLK3_F
running on -2L, -3L, -4L
PLL0
USB_RUN
PLL1
/2
CPU_RUN
PCI_RUN
REF[0-1]
USBCLK/IRCLK
XCPUCLK [0-2]
CPUCLK [0-2]
PCICLK [2-9]
2.5–3.3V Driver
14.318 MHz
96 MHz
48 MHz
8 MHZ
D
CK
CPUCLK
PCICLK
/2
/12
D
CK
D
CK
PCICLK_F [0-1]
on -1L, -3L, -4L only; not free-
D
CK
D
CK
D
CK
running on -2L
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| CY22800-082A | Universal Programmable Clock Generator (UPCG) |
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| CY22800-001A | Universal Programmable Clock Generator (UPCG) |
| CY22800-002A | Universal Programmable Clock Generator (UPCG) |
相關(guān)代理商/技術(shù)參數(shù) |
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| CY2278APAC-1L | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:CPU System Clock Generator |
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| CY2278APC-2L | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:CPU System Clock Generator |
| CY2278APC-3L | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:CPU System Clock Generator |
| CY2278APC-4L | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:CPU System Clock Generator |
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