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How to Read Datasheets
For every electronic component or series of components, the
manufacturer or designer produces a data sheet. In its early stages,
a data sheet might be the specifications the designer works from;
but, by the time the device is released, the data sheet is the
essential piece of information that describes exactly what the
component does. Everything from the smallest resistor to the most
elaborate processor needs a datasheet. Datasheets focus on electrical
properties and the pin functions of the device; usually the inner
workings of the device are not discussed. This is partly to make
industrial espionage more difficult, and also because the user should
not need to know the internal workings of the device. In practice, if
you find that you need to know how a particular product works
internally, you can often call the manufacturer and find out what you
need to know.
In addition to datasheets, devices with complex configurations or
applications may have related documents to help the designer work
with their products. These are called ?°application notes,?ą
?°user?És guides,?ą ?°designer?És guides,?ą ?°package
drawings,?ą etc. These documents are usually just as necessary as the
datasheet. In general, it is best to get the datasheet directly from
the company website relatively often because occasionally there is
errata or new information to be found in the datasheets. Datasheets
are invariably covered with legal disclaimers as to the accuracy,
permanency, and utility of the document. Below are some of the kinds
of things you might find in a datasheet and explanations of their
usual meaning.
Official name of the part or series, part numbers and part number
variations and manufacturer release date of the datasheet. Part
number variations usually indicate alternative packaging or
temperature tolerance. For component families, a chart might be
provided to helpfully graph all of the family members. Price is
usually not indicated on a datasheet.
An overview of the parts purpose and features is usually included near
the beginning. This is what you scan to see if the part is what you
think it is.
The electrical operating characteristics section of a datasheet
indicates the minimum and maximum voltage and current parameters for
the chip as a whole and for individual pins. Power requirements for
the chip as a whole are essential. The power supply circuitry of the
device must be able to support all of the components. Operating
frequencies of clocks or information are often indicated here. Pin
electrical characteristics are important when using the pin to drive
larger loads. Lower power integrated circuits are not always capable
of driving an LED, for example. Noise tolerance of the power supply,
or noise created by the component might also be found here.
Capacitance, inductance, and resistance caused by the component might
also be found here. These are especially important for high-speed
circuit analysis.
The datasheet should also note the tolerances of the device. While the
above operating characteristics indicated what conditions are needed
for the device to operate as promised, the tolerances indicate the
maximum and minimum conditions the component can handle without
permanent damage. Both the operating conditions and the tolerances
should indicate the nature of the testing experiments. Voltage,
temperature, moisture, air pressure, ultraviolet radiation, and
physical stress are possible tolerance conditions.
The arrangement and name of each pin on the chip is a necessity on any
integrated circuit (IC) datasheet. The diagram should specify whether
the diagram is from a point of view above or below the chip and list
the pins by name or number. Pin functional descriptions should
accompany the pin map diagram to explain the basic purpose of each
pin. If this short description is insufficient, a more elaborate
explanation is usually included later in the datasheet. Often the
short descriptions may not be 100% clear to a novice data sheet
reader because of abbreviations or conventions. If the data sheet
doesn?Ét fully explain what the short description means, the
term is probably common enough to be found elsewhere on the Internet.
A block diagram of architecture might be included for more complex
devices. Other internal descriptions might be provided, but usually
the description is limited to the parts of the system that the user
can access.
Waveforms of input or outputs are common. This is especially true for
explaining bus operation and data formats. Timing diagrams and
information are also essential for finding interoperable devices.
Just because two components use the same bus protocol does not always
mean they can talk to each other. Checking this information is always
a good idea.
Graphs of I/V curves, noise profiles, input response, performance
descriptions are very common. For system/control behavior this can be
useful, but the testing conditions are not always entirely clear. This
kind of information is the basis of the analysis many engineers do,
but the graphs are rarely a good substitute for prototyping.
Many kinds of components only work if accompanied by necessary passive
components. Usually these systems provide an ?°example?ą configuration
that will produce a known behavior. Examples are very useful if you
have the same needs the example configuration claims to meet, but the
datasheet should also include the formulas and explanation necessary
to pick your own accompanying components.
Distribution information and manufacturing or assembly advice might
also be found in a datasheet. For example, a crystal clock might
specify that it should be soldered to the circuit board for no more
than 10 seconds at 400 degrees. For commercial design this kind of
information is useful, as adhering to such recommendations improves
yield.
Mechanical drawing and footprints are the last piece of essential
information a datasheet includes. This will be a drawing of the
physical form of the device, with measurements specified in metric
and American units. For designing a board, it is very important to
understand the drawings because incorrectly interpreting the
relationship among the pins will waste an entire revision of the
board. The usual way of describing the dimensions is to specify a pin
width and spacing precisely, but to give broader tolerances on the
exact length and width of the overall device. What this means is that
the process of manufacturing the ICs tries to control the width and
spacing of the pins, but everything else is somewhat flexible.
ALTERAXilinxActel and Lattice
DISTRIBUTER
Lima Electronics
we are one of the leading agent in China who specialize in the
distribution of international well-known integrate circuit (IC)and
other parts such as ALTERAXilinxActel and Lattice for
the industrial equipments.
Our company headquarter in singapore compared with our
competitors, we're famous for the upstanding reputation and high
quality of business service, becoming the well known supplier of
international components. we keep the slogen in aeternum:quality
techology service---serve you with reliable
qualityhigh-tech supportand good after-sales service
to promote the development between two parties.
CONTACE ME
CONTACE MEMr Luo
MSNluoziqiang@hotmail.com
Mobile137-1457-2551 QQ107521149
Tel0755-8836 5152Shenzhen
Httpwww.lima-power.com.sg
We have distributers in shenzhenHongkong and singapore.
-------------= Posted from Ugroups.com =-------------
---= Fast & Free Web Portal to Usenet Newsgroups =---
-------------= http://www.ugroups.com/ =-------------
For every electronic component or series of components, the
manufacturer or designer produces a data sheet. In its early stages,
a data sheet might be the specifications the designer works from;
but, by the time the device is released, the data sheet is the
essential piece of information that describes exactly what the
component does. Everything from the smallest resistor to the most
elaborate processor needs a datasheet. Datasheets focus on electrical
properties and the pin functions of the device; usually the inner
workings of the device are not discussed. This is partly to make
industrial espionage more difficult, and also because the user should
not need to know the internal workings of the device. In practice, if
you find that you need to know how a particular product works
internally, you can often call the manufacturer and find out what you
need to know.
In addition to datasheets, devices with complex configurations or
applications may have related documents to help the designer work
with their products. These are called ?°application notes,?ą
?°user?És guides,?ą ?°designer?És guides,?ą ?°package
drawings,?ą etc. These documents are usually just as necessary as the
datasheet. In general, it is best to get the datasheet directly from
the company website relatively often because occasionally there is
errata or new information to be found in the datasheets. Datasheets
are invariably covered with legal disclaimers as to the accuracy,
permanency, and utility of the document. Below are some of the kinds
of things you might find in a datasheet and explanations of their
usual meaning.
Official name of the part or series, part numbers and part number
variations and manufacturer release date of the datasheet. Part
number variations usually indicate alternative packaging or
temperature tolerance. For component families, a chart might be
provided to helpfully graph all of the family members. Price is
usually not indicated on a datasheet.
An overview of the parts purpose and features is usually included near
the beginning. This is what you scan to see if the part is what you
think it is.
The electrical operating characteristics section of a datasheet
indicates the minimum and maximum voltage and current parameters for
the chip as a whole and for individual pins. Power requirements for
the chip as a whole are essential. The power supply circuitry of the
device must be able to support all of the components. Operating
frequencies of clocks or information are often indicated here. Pin
electrical characteristics are important when using the pin to drive
larger loads. Lower power integrated circuits are not always capable
of driving an LED, for example. Noise tolerance of the power supply,
or noise created by the component might also be found here.
Capacitance, inductance, and resistance caused by the component might
also be found here. These are especially important for high-speed
circuit analysis.
The datasheet should also note the tolerances of the device. While the
above operating characteristics indicated what conditions are needed
for the device to operate as promised, the tolerances indicate the
maximum and minimum conditions the component can handle without
permanent damage. Both the operating conditions and the tolerances
should indicate the nature of the testing experiments. Voltage,
temperature, moisture, air pressure, ultraviolet radiation, and
physical stress are possible tolerance conditions.
The arrangement and name of each pin on the chip is a necessity on any
integrated circuit (IC) datasheet. The diagram should specify whether
the diagram is from a point of view above or below the chip and list
the pins by name or number. Pin functional descriptions should
accompany the pin map diagram to explain the basic purpose of each
pin. If this short description is insufficient, a more elaborate
explanation is usually included later in the datasheet. Often the
short descriptions may not be 100% clear to a novice data sheet
reader because of abbreviations or conventions. If the data sheet
doesn?Ét fully explain what the short description means, the
term is probably common enough to be found elsewhere on the Internet.
A block diagram of architecture might be included for more complex
devices. Other internal descriptions might be provided, but usually
the description is limited to the parts of the system that the user
can access.
Waveforms of input or outputs are common. This is especially true for
explaining bus operation and data formats. Timing diagrams and
information are also essential for finding interoperable devices.
Just because two components use the same bus protocol does not always
mean they can talk to each other. Checking this information is always
a good idea.
Graphs of I/V curves, noise profiles, input response, performance
descriptions are very common. For system/control behavior this can be
useful, but the testing conditions are not always entirely clear. This
kind of information is the basis of the analysis many engineers do,
but the graphs are rarely a good substitute for prototyping.
Many kinds of components only work if accompanied by necessary passive
components. Usually these systems provide an ?°example?ą configuration
that will produce a known behavior. Examples are very useful if you
have the same needs the example configuration claims to meet, but the
datasheet should also include the formulas and explanation necessary
to pick your own accompanying components.
Distribution information and manufacturing or assembly advice might
also be found in a datasheet. For example, a crystal clock might
specify that it should be soldered to the circuit board for no more
than 10 seconds at 400 degrees. For commercial design this kind of
information is useful, as adhering to such recommendations improves
yield.
Mechanical drawing and footprints are the last piece of essential
information a datasheet includes. This will be a drawing of the
physical form of the device, with measurements specified in metric
and American units. For designing a board, it is very important to
understand the drawings because incorrectly interpreting the
relationship among the pins will waste an entire revision of the
board. The usual way of describing the dimensions is to specify a pin
width and spacing precisely, but to give broader tolerances on the
exact length and width of the overall device. What this means is that
the process of manufacturing the ICs tries to control the width and
spacing of the pins, but everything else is somewhat flexible.
ALTERAXilinxActel and Lattice
DISTRIBUTER
Lima Electronics
we are one of the leading agent in China who specialize in the
distribution of international well-known integrate circuit (IC)and
other parts such as ALTERAXilinxActel and Lattice for
the industrial equipments.
Our company headquarter in singapore compared with our
competitors, we're famous for the upstanding reputation and high
quality of business service, becoming the well known supplier of
international components. we keep the slogen in aeternum:quality
techology service---serve you with reliable
qualityhigh-tech supportand good after-sales service
to promote the development between two parties.
CONTACE ME
CONTACE MEMr Luo
MSNluoziqiang@hotmail.com
Mobile137-1457-2551 QQ107521149
Tel0755-8836 5152Shenzhen
Httpwww.lima-power.com.sg
We have distributers in shenzhenHongkong and singapore.
-------------= Posted from Ugroups.com =-------------
---= Fast & Free Web Portal to Usenet Newsgroups =---
-------------= http://www.ugroups.com/ =-------------