Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
fan-out relates to the drive stength of your circuit block
high fan-out circuit means that your circuit can drive BIG capacitance loading
ie. a 16mA LVCMOS driver is a high fan-out circuit
sometime people refers fanout as how many identical circuit your circuit can drive.
ie. faout#= ONE cricuit A output can drive X number of circuit A
LVCMOS is the most common I/O.
16mA is the current that this output buffer can source and sink.
(sometime they don't usually teach students these stuffs in school, but u can learn on your own by reading datasheets and application notes)
this edaboard is a good place 2.
When dealing with standard TTL, a driver gate can "drive" the inputs of approx. 10 unit loads, or 10 other gates. This number 10 means that the standard TTL driver gate has whats called a FANOUT of 10. In other words, if you attempt to put an 11th unit load on the output of a standard TTL gate, NONE OF THE OTHER UNIT LOADS WILL WORK RELIABLY. This is because the voltage level available to each unit load input goes DOWN with each load attached. If you exceed the driver gates FANOUT spec. The voltage level to each unit load input will fall below a "valid high" input for TTL.
Usually Fan-out refers to simillar logic families interfacing. CMOS to CMOS interfacing or TTL to TTL. It is the abillity of a logic output stage to drive - supply - more than one inputs. In other words it is how mach current an output stage can supply and still maintain the specified output voltage levels that can clearly be distinguished as LOGIC 1 and LOGIC 0 by the next stage.
Fan out means the ability of an IC so that it's signals don't decay and can be understood by other devices.....
For example if one IC gives a logic 1 of +5v , then Fan out means how many other IC's connected to this can understand the same meaning.....of logic 1.....i:e related to the signal strength.........
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
