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参数资料
| 型号： | W218 |
| 英文描述： | Clocks and Buffers |
| 中文描述： | 时钟和缓冲器 |
| 文件页数： | 3/17页 |
| 文件大小： | 175K |
| 代理商： | W218 |
W218
Document #: 38-07221 Rev. *A
Page 3 of 17
Overview
The W218 is a highly integrated frequency timing generator,
supplying all the required clock sources for an Intel
architec-
ture platform using graphics integrated core logic.
Functional Description
I/O Pin Operation
REF0/FSEL1is a dual-purpose l/O pin. Upon power-up the pin
acts as a logic input. If the pin is strapped to a HIGH state
externally, CPU clock outputs will run at 133 MHz. If it is
strapped LOW, CPU clock outputs will be determined by the
status of FSEL input pin. An external 10-k
strapping resistor
should be used.
Figure 1
shows a suggested method for strap-
ping resistor connections.
After 2 ms, the pin becomes an output. Assuming the power
supply has stabilized by then, the specified output frequency
is delivered on the pins. If the power supply has not yet
reached full value, output frequency initially may be below tar-
get but will increase to target once supply voltage has stabi-
lized. In either case, a short output clock cycle may be pro-
duced from the CPU clock outputs when the outputs are
enabled.
Pin Selectable Functions
Table 1
outlines the device functions selectable through
Threestate#, FSEL0 and FSEL1. Specific outputs available at
each pin are detailed in
Table 2
below. The SEL0 pin requires
a 220
pull-up resistor to 3.3V for the W218 to sense the max-
imum host bus frequency of the processor and configure itself
accordingly. Also note that FSEL0, Threestate# input levels
should be stable within 500
μ
s of the later of V
DDQ3
, V
DDQ2
,
PWR_DWN# rising edge.
Notes:
2.
3.
4.
5.
6.
7.
Provided for board-level
“
bed of nails
”
testing.
“
Normal
”
mode of operation.
TCLK is a test clock overdriven on the XTAL_IN input during test mode.
Required for DC output impedance verification.
Range of reference frequency allowed is min. = 14.316 MHz, nominal = 14.31818 MHz, max. = 14.32 MHz.
Frequency accuracy of 48 MHz must be +167 PPM to match USB default.
Power-on
Reset
Timer
Output Three-state
Data
Latch
Hold
Output
Low
Q
D
W218
V
DD
Clock Load
10 k
Output
(Load Option 1)
10 k
(Load Option 0)
Output Strapping Resistor
Series Termination Resistor
Figure 1. Input Logic Selection Through Resistor Load Option
Table 2. CK Whitney Truth Table
Tristate#
0
0
1
1
1
1
FSEL0
0
1
0
1
0
1
FSEL1
X
X
0
0
1
1
CPU
Hi-Z
TCLK/4
66 MHz
100 MHz
133 MHz
133 MHz
SDRAM
Hi-Z
TCLK/4
100 MHz
100 MHz
133 MHz
100 MHz
3V66
Hi-Z
TCLK/6
66 MHz
66 MHz
66 MHz
66 MHz
PCI
Hi-Z
48 MHz
Hi-Z
TCLK/2
48 MHz
48 MHz
48 MHz
48 MHz
REF
Hi-Z
TCLK
APIC
Hi-Z
TCLK/12
33 MHz
33 MHz
33 MHz
33 MHz
Notes
2
4, 5
3, 6, 7
3, 6, 7
3, 6, 7
3, 6, 7
TCLK/12
33 MHz
33 MHz
33 MHz
33 MHz
14.318 MHz
14.318 MHz
14.318 MHz
14.318 MHz
相关PDF资料 |
PDF描述 |
|---|---|
| W219 | Clocks and Buffers |
| W219B | Frequency Generator for Integrated Core Logic with 133-MHz FSB |
| W22010AI-20 | x4 SRAM |
| W22010AJ-12 | x4 SRAM |
| W22010AJ-15 | x4 SRAM |
相关代理商/技术参数 |
参数描述 |
|---|---|
| W218200J | 制造商:TT Electronics / IRC 功能描述:Wirewound Resistor - Vitreous Enamel |
| W21-8200J | 制造商:TT Electronics / IRC 功能描述:RESISTOR, WIREWOUND, 820 OHM, 3W, 5%; Product Range:INTERNATIONAL RESISTIVE - W20 Series; Resistance:820ohm; Power Rating:3W; Resistance Tolerance: 5%; Resistor Case Style:Axial Leaded; Resistor Element Type:Ceramic; No. of Pins:2 ;RoHS Compliant: Yes |
| W218200JA | 功能描述:线绕电阻器 - 透孔 820ohm 3watt 5% RoHS:否 制造商:Bourns 电阻:10 Ohms 容差:5 % 功率额定值:7 W 温度系数:200 PPM / C 系列:FW 端接类型:Axial 工作温度范围:- 55 C to + 155 C 尺寸:9.5 mm Dia. x 26 mm L 封装:Ammo 产品:Power Resistors Wirewound High Energy |
| W218200JALF | 功能描述:线绕电阻器 - 透孔 820ohm 3watt 5% RoHS:否 制造商:Bourns 电阻:10 Ohms 容差:5 % 功率额定值:7 W 温度系数:200 PPM / C 系列:FW 端接类型:Axial 工作温度范围:- 55 C to + 155 C 尺寸:9.5 mm Dia. x 26 mm L 封装:Ammo 产品:Power Resistors Wirewound High Energy |
| W218201JA | 功能描述:线绕电阻器 - 透孔 8.2K 3watt 5% RoHS:否 制造商:Bourns 电阻:10 Ohms 容差:5 % 功率额定值:7 W 温度系数:200 PPM / C 系列:FW 端接类型:Axial 工作温度范围:- 55 C to + 155 C 尺寸:9.5 mm Dia. x 26 mm L 封装:Ammo 产品:Power Resistors Wirewound High Energy |
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