MCP6001U vs 741 op amp - Electronic Circuits Projects Diagrams Free

arhi · 12th May 2008, 04:15 PM

Hi,

I never used this MCP6001U (just saw the ds for it few minutes ago first time in my life), is there any "expert" that can tell me can I replace it with simple 741?

EDIT: more info - I'm using it to oscilate mosfet to pull up the voltage from 5 to 14V so nothing "smart/sensitive"

audioguru · 12th May 2008, 04:38 PM

A lousy old 741 opamp is 40 years old. It is designed for low frequencies because its max frequency for full output is only 9kHz. It is designed for a 30V supply. Its inputs and outputs don't work when they are within about 3V from a positive or negative supply voltage.

The MCP6001 is designed for a 1.8V to 6.0V supply. It produces full output up to 30kHz. Its inputs work fine at either supply voltage and when the load current is low the outputs go to either supply voltage.

arhi · 12th May 2008, 04:55 PM

Quote:

Originally Posted by audioguru

A lousy old 741 opamp is 40 years old. It is designed for low frequencies because its max frequency for full output is only 9kHz. It is designed for a 30V supply. Its inputs and outputs don't work when they are within about 3V from a positive or negative supply voltage.

The MCP6001 is designed for a 1.8V to 6.0V supply. It produces full output up to 30kHz. Its inputs work fine at either supply voltage and when the load current is low the outputs go to either supply voltage.

Thanks for the quick answer. I knew most of this, (had no idea about 3V dead zone) ... the frequency is not big issue as I'm only using it to oscilate mosfet to get from 5V to 14V so it's maybe 3KHz... and in this 5th world country, I cannot find the MCP6001 that looks ideal for the job .. the OP's I have at home are:
739, 741, 747, 748, CA3054, L272, L272M, LM224N, LM2904N, LM308N, LM3900N, LM392N, LM833N, MC4558CN and RC4559N ...

now, with what I know about OP's (and that's not much) any of these should be able to "drive" the mosfet to generate V I need. but, I have all these lying around (more then 50 741's

) so that's why I asked about it first, but if you can recognise a good one among these ones I mentioned above

I will be grateful

audioguru · 12th May 2008, 05:06 PM

Most Mosfets don't work unless their gate gets +10V.
Most of your old opamps don't work when their supply is less than about 12V except the LM224 and LM2904 are fine. But with a 5V supply, their output high voltage is only +3.8V which is much too low for most Mosfets.

Post your schematic showing a load current for the Mosfet for us to make suggestions.

arhi · 12th May 2008, 05:32 PM

Quote:

Originally Posted by audioguru

Post your schematic showing a load current for the Mosfet for us to make suggestions.

Here it is... I'm not sure if that's a good mosfet for the job, nor which opamp to use

.. This is the "salvaged" schematic from piece of paper in my desk

.. the mosfet and the opamp on the schematic are "approx" I'm not sure which ones to use

arhi · 12th May 2008, 06:12 PM

argh .. ignore this .. this is just a part of the schematic .. and I do not like it anyway so i'll redo it myself from scratch

audioguru · 12th May 2008, 06:29 PM

The circuit doesn't have a load and has no load current.
The Mosfet shorts 14V to 5V through its body diode.
The non-inverting input of the opamp is connected to +7V which might destroy it.
The Mosfet is tiny.

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12th May 2008, 04:15 PM	(permalink)
arhi	MCP6001U vs 741 op amp Hi, I never used this MCP6001U (just saw the ds for it few minutes ago first time in my life), is there any "expert" that can tell me can I replace it with simple 741? EDIT: more info - I'm using it to oscilate mosfet to pull up the voltage from 5 to 14V so nothing "smart/sensitive" __________________ http://www.it4um.com Last edited by arhi; 12th May 2008 at 04:25 PM.

12th May 2008, 04:38 PM	(permalink)
audioguru	A lousy old 741 opamp is 40 years old. It is designed for low frequencies because its max frequency for full output is only 9kHz. It is designed for a 30V supply. Its inputs and outputs don't work when they are within about 3V from a positive or negative supply voltage. The MCP6001 is designed for a 1.8V to 6.0V supply. It produces full output up to 30kHz. Its inputs work fine at either supply voltage and when the load current is low the outputs go to either supply voltage. __________________ Uncle $crooge

12th May 2008, 05:06 PM	(permalink)
audioguru	Most Mosfets don't work unless their gate gets +10V. Most of your old opamps don't work when their supply is less than about 12V except the LM224 and LM2904 are fine. But with a 5V supply, their output high voltage is only +3.8V which is much too low for most Mosfets. Post your schematic showing a load current for the Mosfet for us to make suggestions. __________________ Uncle $crooge

12th May 2008, 06:12 PM	(permalink)
arhi	argh .. ignore this .. this is just a part of the schematic .. and I do not like it anyway so i'll redo it myself from scratch __________________ http://www.it4um.com

12th May 2008, 06:29 PM	(permalink)
audioguru	The circuit doesn't have a load and has no load current. The Mosfet shorts 14V to 5V through its body diode. The non-inverting input of the opamp is connected to +7V which might destroy it. The Mosfet is tiny. __________________ Uncle $crooge