LMC662 Voltage Output Swing vs Load

Thread Starter

Matherios

Joined Feb 25, 2018
74
Hello i have a LMC662 on a circuit on a homework with supply voltage 12v(single supply) and load of 2K.
I went on the datasheet but i can't find what the voltage output swing will be with 2K resistor,if somebody could help me i would appreciate it.
MOD:
Added the datasheet for you.
 

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ericgibbs

Joined Jan 29, 2010
18,766
hi M,
Look at this clip from the datasheet, plot a simple graph showing the 5V and 15V points [for 2k load], join them with a line, interpolate the 12V level.
As a double check plot the Vsupply - Vout max, again interpolate for 12V.
Post your calculations so that we can check.
E
AA1 13-Oct-18 18.35.gif
 

ericgibbs

Joined Jan 29, 2010
18,766
hi M,
Did you do the simple graph I suggest.?
As it is Homework we cannot give you a direct answer.
E
EDIT:
Use the Red boxed typical values.
AA1 13-Oct-18 18.35.gif
 
Last edited:

crutschow

Joined Mar 14, 2008
34,283
More appropriate might be use the 5V output for the 600Ω load since that is closer to the same output current as 12V with a 2kΩ load.
Note that the output voltage drop from the positive rail is similar for different rail voltages at similar output currents.
 

ericgibbs

Joined Jan 29, 2010
18,766
hi,
You have the value for 5v and 15v.
ie: 4.87v and 14.63v
For a supply of 5v and 15v
So
5v-4.87v = 0.13v
15v - 14.63v = 0.37v

So work out the rate of fall in the Vout, from 5v compared to 15v, [over a10 volt range] that will give fall in Vout/Volt increase in Vsupply.
Can you do that OK.?

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ericgibbs

Joined Jan 29, 2010
18,766
hi M,
My calculations show that the output resistance falls slightly from 5V to 15V operation

Using a value of the calculated output resistance and the method as suggested in post #9, they agree in the Vout value at 12Vsupply.

When you have your final answer, please post, so that we can compare results.

E
 
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