What is meant by a complimentary pair mosfet

Thread Starter

MikeJacobs

Joined Dec 7, 2019
162
So in my quest to fully understand data sheets.

What is meant by a complimentary pair of MOSFETs?

I was recently looking for an IC that had both a P and N Chanel in one package.
I don't intend for them to have any interactions together. I just wanted two fets in one pack

I stumbled upon this complimentary pair option. The block diagram makes it look like its just two fets in one pack
However something tells me its more then that.

Can you run them independently of each other?

I gather this is what makes up CMOS logic but if you want to run them independent and just using a complimentary pair for convenience is there any issue?
 
Last edited:

MrChips

Joined Oct 2, 2009
21,818
You can buy transistors in matched pairs, MOSFETs as well as BJTs.
It means that the characteristics and transfer functions are closely matched and are suitable for push-pull amplifier applications.

Here are examples of push-pull output stages:

1578281818271.png



1578281764024.png
 

jpanhalt

Joined Jan 18, 2008
10,210
Yes, they can be treated separately.

The IRF7105 is one example. You can also get pairs that are not complementary, such as the dual N-channel IRF7103.
 

Delta prime

Joined Nov 15, 2019
482
electronics may be understood as a branch of science that utilizes and controls the flow of electrons through specially designed networks of active and passive devices to produce a desired result. To better understand not only (Datasheets) but any
Or all types of electronic components, is to start building simple circuits . You're putting the cart before the horse. The answers given here will only cause confusion to you and will raise an order of magnitude more questions.
 

atferrari

Joined Jan 6, 2004
4,088
electronics may be understood as a branch of science that utilizes and controls the flow of electrons through specially designed networks of active and passive devices to produce a desired result. To better understand not only (Datasheets) but any
Or all types of electronic components, is to start building simple circuits . You're putting the cart before the horse. The answers given here will only cause confusion to you and will raise an order of magnitude more questions.
??
He asked about complementary pairs.
 

OBW0549

Joined Mar 2, 2015
3,545
What is meant by a complimentary pair of MOSFETs?
The usual usage of the term "complementary" is to indicate that two devices of opposite polarity have characteristics that are roughly similar. Some examples are the TIP122/TIP127 complimentary Darlingtons, the 2N3904 and 2N3906, the 2N4401 and 2N4403, and the ZVN3306 and ZVP3306 low-power MOSFETs.

"Pair" simple implies the two devices are in one package (which is what you were looking for).

(Note that "complementary pair" is NOT the same thing as "matched pair." The latter refers to devices, usually of the same polarity and in the same package, which have characteristics that are as identical as possible. Two examples would be the LM194 and the MAT12.)

I was recently looking for an IC that had both a P and N Chanel in one package.
I don't intend for them to have any interactions together. I just wanted two fets in one pack

I stumbled upon this complimentary pair option. The block diagram makes it look like its just two fets in one pack
However something tells me its more then that.
We can help you better if you'd tell us what device you're looking at or post a link to its data sheet. Otherwise, we have to guess.

Can you run them independently of each other?
Maybe. Maybe not.

If the two devices are constructed on two separate pieces of silicon and merely housed in the same IC package, you can almost certainly use them independently. However, if the two devices are fabricated on one piece of silicon, their independence might be restricted by limits on how much voltage is allowable between the terminals of one device and the terminals of the other; if so, it will be indicated in the Absolute Maximum Ratings section of the data sheet.
 

Thread Starter

MikeJacobs

Joined Dec 7, 2019
162
Thanks everyone for the continued great support on this forum
Very interesting point OBWO549 makes there
Will have to study up on this

What would tell you in the data sheet that it’s on a single substrate or merely packaged together?

I don’t really have a part number to share.
Anyone have any suggestions ?
Say a 12v vdds part with an Id of 500 mA and a logic level VGSth?
 

MrChips

Joined Oct 2, 2009
21,818
Dual transistors in the same package are intended for low drift temperature stable differential long-tail pair DC amplifiers.
These would be identical transistors, not complimentary.

1578367590770.png
 

jpanhalt

Joined Jan 18, 2008
10,210
@MikeJacobs
I thought you wanted mosfets. I suggested one (IRF7105), but without knowing your requirements for gate drive voltage and current, it is impossible to suggest anything that might be appropriate.
 

Thread Starter

MikeJacobs

Joined Dec 7, 2019
162
@MikeJacobs
I thought you wanted mosfets. I suggested one (IRF7105), but without knowing your requirements for gate drive voltage and current, it is impossible to suggest anything that might be appropriate.
I did want mosfets
I think the post above was just an example

In my above post I mentioned

I don’t really have a part number to share.
Anyone have any suggestions ?
Say a 12v vdds part with an Id of 500 mA and a logic level VGSth?

Thanks to everyone for all the good conversation
Always lots to learn here
 

Wolframore

Joined Jan 21, 2019
1,779
Just be careful and look at the datasheets, sometimes the source or drains are connected and may make using them as two separate mosfets impossible. If you are looking for a part look at Digi-Key or mouser and use their parametric search.
 

jpanhalt

Joined Jan 18, 2008
10,210
Say a 12v vdds part with an Id of 500 mA and a logic level VGSth?

Thanks to everyone for all the good conversation
Always lots to learn here
The IRF7105 meets those specifications, but I don't think you mean logic level Vgs(th). That is the voltage at which the gate first starts to conduct. You want it conducting better than that at logic level (5V?).

I would look for one with a lower "on" Vgs.
 
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