参数资料
| 型号： | ADT7468ZEVB |
| 厂商： | ON Semiconductor |
| 文件页数： | 38/81页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL FOR ADT7468 |
| 标准包装： | 1 |
| 其它名称： | EVAL-ADT7468EB EVAL-ADT7468EB-ND |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页当前第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页第55页第56页第57页第58页第59页第60页第61页第62页第63页第64页第65页第66页第67页第68页第69页第70页第71页第72页第73页第74页第75页第76页第77页第78页第79页第80页第81页
ADT7468
DYNAMIC T MIN CONTROL MODE
VENTS
FAN
FAN
In addition to the automatic fan speed control mode described
I/O CARDS
POWER
VENTS
I/O CARDS
POWER
in the Automatic Fan Control Overview section, the ADT7468
SUPPLY
SUPPLY
has a mode that extends the basic automatic fan speed control
loop. Dynamic T MIN control allows the ADT7468 to intelligently
GOOD CPU AIRFLOW
CPU
POOR CPU
AIRFLOW
CPU
adapt the system’s cooling solution for best system performance
or lowest possible system acoustics, depending on user or
FAN
DRIVE
BAYS
DRIVE
BAYS
design requirements. Use of dynamic T MIN control alleviates the
need to design for worst-case conditions and significantly
reduces system design and validation time.
VENTS
GOOD VENTING =
GOOD AIR EXCHANGE
POOR VENTING =
POOR AIR EXCHANGE
Designing for Worst-Case Conditions
Figure 50. Chassis Airflow Issues
System design must always allow for worst-case conditions. In
PC design, the worst-case conditions include, but are not
limited to the following:
?
Worst-Case Processor Power Consumption
This data sheet maximum does not necessarily reflect the
true processor power consumption. Designing for worst-
?
Worst-Case Altitude
A computer can be operated at different altitudes. The
case CPU power consumption can result in a processor
becoming overcooled (generating excess system noise).
altitude affects the relative air density, which alters the
effectiveness of the fan cooling solution. For example,
comparing 40°C air temperature at 10,000 ft. to 20°C air
temperature at sea level, relative air density is increased by
40%. This means that the fan can spin 40% slower and
make less noise at sea level than at 10,000 ft., while keeping
the system at the same temperature at both locations.
?
?
Worst-Case Peripheral Power Consumption
The tendency is to design to data sheet maximums for
peripheral components (again overcooling the system).
Worst-Case Assembly
Every system manufactured is unique because of
manufacturing variations. Heat sinks may be loose fitting
?
Worst-Case Fan
Due to manufacturing tolerances, fan speeds in RPM are
normally quoted with a tolerance of ±20%. The designer
needs to assume that the fan RPM can be 20% below
tolerance. This translates to reduced system airflow and
elevated system temperature. Note that fans 20% out of
or slightly misaligned. Too much or too little thermal
grease might be used, or variations in application pressure
for thermal interface material could affect the efficiency of
the thermal solution. Accounting for manufacturing
variations in every system is difficult; therefore, the system
must be designed for the worst case.
tolerance can negatively impact system acoustics, because
they run faster and generate more noise.
HEAT
SINK
θ SA
θ TIMS
T A
T S
θ CA
?
Worst-Case Chassis Airflow
The same motherboard can be used in a number of
THERMAL
INTERFACE
MATERIAL
θ CTIM
T TIM
T C
θ CS
θ JA
θ TIMC
PROCESSOR
different chassis configurations. The design of the chassis
and the physical location of fans and components
determine the system thermal characteristics. Moreover,
for a given chassis, the addition of add-in cards, cables, or
INTEGRATED
HEAT
SPREADER
SUBSTRATE θ JTIM
EPOXY
THERMAL INTERFACE MATERIAL
T TIM
T J
other system configuration options can alter the system
airflow and reduce the effectiveness of the system cooling
solution. The cooling solution can also be inadvertently
altered by the end user. For example, placing a computer
against a wall can block the air ducts and reduce system
airflow.
Figure 51. Thermal Model
Although a design usually accounts for worst-case conditions in
all these cases, the actual system is almost never operated at
worst-case conditions. The alternative to designing for the worst
case is to use the dynamic T MIN control function.
Rev. 3 | Page 38 of 81 | www.onsemi.com
相关PDF资料 |
PDF描述 |
|---|---|
| ADT7473ZEVB | BOARD EVALUATION FOR ADT7473 |
| ADT7475EBZEVB | BOARD EVALUATION FOR ADT7475 |
| ADT7476EBZEVB | BOARD EVALUATION FOR ADT7476 |
| ADT7490ZEVB | BOARD EVALUATION FOR ADT7490 |
| ADZS-21262-1-EZEXT | BOARD DAUGHTER FOR ADSP-21262 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ADT7470 | 制造商:AD 制造商全称:Analog Devices 功能描述:Temperature Sensor Hub and Fan Controller |
| ADT7470_13 | 制造商:AD 制造商全称:Analog Devices 功能描述:Temperature Sensor Hub and Fan Controller |
| ADT7470ARQ | 制造商:Analog Devices 功能描述:Temp Sensor Digital Serial (I2C) 16-Pin QSOP |
| ADT7470ARQ-REEL | 制造商:Rochester Electronics LLC 功能描述: 制造商:Analog Devices 功能描述: |
| ADT7470ARQ-REEL7 | 制造商:Analog Devices 功能描述:Temp Sensor Digital Serial (I2C) 16-Pin QSOP T/R |
发布紧急采购，3分钟左右您将得到回复。