Op-Amp supply voltage

[ballimo]

Hello All,

I am using a op-Amp as a difference amplifier, the output voltage of the op-Amp is between 4 and 5.2V.
My question is: does a supply voltages of 0 and 5.2V work? i have do a quick simulation the result show that I have to use a supply > 5.2V to obtain the result I want. so what should be the supply voltage? can I find this information in the datasheet?

Thanks in Advance,

Ballimo

 

[singhania12]

which op-amp you r using
search for its datasheet
you can easily get the operating voltage from there
this is the datasheet for national's opamp

**broken link removed**

 

[ballimo]

Yes, I know you can get easily the operating voltage from the datasheet but this is not my question.
My question is if the output of the op-amp is 5.2V, in the datasheet the supply voltage is from 2V to +/-15V, I want to know what should be the supply voltage to have a 5.2V output without problem? theoretically 0 and 5.2V should work, but I think I need to use 0 and > 5.2V to obtain 5.2V at the output. So what is this minimum value >5.2V.

Thanks,
Ballimo

 

[karesz]

Hi ballimo,
you must read the IC specific datasheet!
Your Op has some max. specified output voltage(range) with the specially used supply voltages ()usual+/-5V or +/-15V...!
Its minimum atable specified, that w. +/- Vsupply=15V it can deliver from i.e.-12.5V &up to +13.0V.
Often you will read: -Vs +2.5V (same as befor I wrote), & 2.0V less as +Vs...
K.

 

[ballimo]

Hi Karesz,

you always give the best answer to my question.
I didn't know that this information can be found in the datasheet.
I am using LT1498 OP-Amp, I checked the datasheet, I did not find the range.
Have you used this Op-amp before?

Thanks,

Ballimo

 

[keith1200rs]

According to the datasheet, the opamp will work to 10mV of the positive rail (worst case) with no load. If you have 0.5mA load then it will only get within 100mV of the positive rail. So, if you want an output of 5.2V I would say you need to power it off at least 5.3V.

Keith.

Added after 44 seconds:

Edit: those figures were at 25C. For working over a temperature range they will be a little worse.

 

[ballimo]

Hi Keith,

what they mean by Vol an Voh? these are the voltage swing at the high and low supply voltage (per example it the supply voltages are 0 and 5V, Vol is at 0V and Voh at 5V) right?

Thanks,

Ballimo

 

[keith1200rs]

Different manufacturers quote them in different ways. In this case:

Vol is how low the output can go.

Voh is how high it can go RELATIVE to Vs. Normally this would be quoted as Vs-10mV rather than simply 10mV.

The values on page 3 are valid for Vs=5V and Vs=3V. On page 8 it gives values for +-/-15V (although they look pretty similar).

Keith.