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參數(shù)資料
| 型號： | ASM2I9940LG-32-LT |
| 廠商： | ALLIANCE SEMICONDUCTOR CORP |
| 元件分類： | 時鐘及定時 |
| 英文描述： | Low Voltage 1:18 Clock Distribution Chip |
| 中文描述： | 9940 SERIES, LOW SKEW CLOCK DRIVER, 18 TRUE OUTPUT(S), 0 INVERTED OUTPUT(S), PQFP32 |
| 封裝： | 7 X 7 MM, 0.80 MM PITCH, GREEN, LQFP-32 |
| 文件頁數(shù)： | 8/13頁 |
| 文件大?。?/td> | 223K |
| 代理商： | ASM2I9940LG-32-LT |
June 2005
rev 1.0
Power Consumption of the ASM2I9940L and
Thermal Management
ASM2I9940L
Low Voltage 1:18 Clock Distribution Chip
8 of
13
Notice: The information in this document is subject to change without notice.
The ASM2I9940L AC specification is guaranteed for the
entire operating frequency range up to 250MHz. The
ASM2I9940L power consumption and the associated
long-term reliability may decrease the maximum
frequency limit, depending on operating conditions such
as clock frequency, supply voltage, output loading,
ambient temperature, vertical convection and thermal
conductivity of package and board. This section
describes the impact of these parameters on the junction
temperature and gives a guideline to estimate the
ASM2I9940L die junction temperature and the associated
device reliability.
Table 11. Die junction temperature and MTBF
Junction temperature
(
°
C)
MTBF (Years)
100
110
120
130
20.4
9.1
4.2
2.0
Increased power consumption will increase the die
junction temperature and impact the device reliability
(MTBF). According to the system-defined tolerable
MTBF, the die junction temperature of the ASM2I9940L
needs to be controlled and the thermal impedance of the
board/package
should
be
dissipated in the ASM2I9940L is represented in
equation 1.
+
=
optimized.
The
power
Where I
CCQ
is the static current consumption of the
ASM2I9940L, C
PD
is the power dissipation capacitance
per output, (M)
∑
C
L
represents the external capacitive
output load, N is the number of active outputs (N is
always 12 in case of the ASM2I9940L). The ASM2I9940L
supports driving transmission lines to maintain high signal
integrity and tight timing parameters. Any transmission
line will hide the lumped capacitive load at the end of the
board trace, therefore,
∑
C
L
is zero for controlled
transmission line systems and can be eliminated from
equation 1. Using parallel termination output termination
results in equation 2 for power dissipation.
In equation 2, P stands for the number of outputs with a
parallel or thevenin termination, V
OL
, I
OL
, V
OH
and I
OH
are
a function of the output termination technique and DC
Q
is
the clock signal duty cycle. If transmission lines are used
∑
C
L
is zero in equation 2 and can be eliminated. In
general, the use of controlled transmission line
techniques eliminates the impact of the lumped capacitive
loads at the end lines and greatly reduces the power
dissipation of the device. Equation 3 describes the die
junction temperature T
J
as a function of the power
consumption.
Where R
thja
is the thermal impedance of the package
(junction to ambient) and T
A
is the ambient temperature.
According to Table 11, the junction temperature can be
used to estimate the long-term device reliability. Further,
combining equation 1 and equation 2 results in a
maximum operating frequency for the ASM2I9940L in a
series terminated transmission line system, equation 4.
(
)
(
+
)
[
]
(
)
4
1
N
3
2
1
1
2
Equation
V
I
R
T
T
V
C
f
Equation
R
P
T
T
Equation
V
I
V
V
I
DC
C
C
N
f
V
I
V
P
Equation
V
C
C
N
f
V
I
P
CC
CCQ
thja
A
JMAX
CC
PD
CLOCKMAX
thja
TOT
A
J
P
OL
OL
Q
OH
CC
OH
Q
M
L
PD
CLOCK
CC
CCQ
CC
TOT
CC
M
L
PD
CLOCK
CC
CCQ
TOT
=
+
=
+
+
+
=
∑
+
∑
∑
相關PDF資料 |
PDF描述 |
|---|---|
| ASM2I9942CG-32-ER | Low Voltage 1:18 Clock Distribution Chip |
| ASM2I9942CG-32-ET | Low Voltage 1:18 Clock Distribution Chip |
| ASM2I9942CG-32-LR | Low Voltage 1:18 Clock Distribution Chip |
| ASM2I9942CG-32-LT | Low Voltage 1:18 Clock Distribution Chip |
| ASM2I9942C | Low Voltage 1:18 Clock Distribution Chip |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| ASM2I9942C | 制造商:ALSC 制造商全稱:Alliance Semiconductor Corporation 功能描述:Low Voltage 1:18 Clock Distribution Chip |
| ASM2I9942C-32-ER | 制造商:ALSC 制造商全稱:Alliance Semiconductor Corporation 功能描述:Low Voltage 1:18 Clock Distribution Chip |
| ASM2I9942C-32-ET | 制造商:ALSC 制造商全稱:Alliance Semiconductor Corporation 功能描述:Low Voltage 1:18 Clock Distribution Chip |
| ASM2I9942C-32-LR | 制造商:ALSC 制造商全稱:Alliance Semiconductor Corporation 功能描述:Low Voltage 1:18 Clock Distribution Chip |
| ASM2I9942C-32-LT | 制造商:ALSC 制造商全稱:Alliance Semiconductor Corporation 功能描述:Low Voltage 1:18 Clock Distribution Chip |
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