IRFZ44N replacement?

[Chopperbuilder]

I have some SMP60N06-14 on hand, wondering if they will work to replace IRFZ44N?

 

[Perry Babin]

In what amp?

The drive circuit, in part, determines what will work.

 

[Chopperbuilder]

It is a Precision Power A404.

 

[jan.didden]

If memory serves, the IRZ44N is a low threshold FET. Maybe check to be sure to have a correct replacement.

Jan

 

[mondogenerator]

IRFZ44N

Hi,

Aren't these still available at say DigiKey?

If I recall these devices are supposed logic level threshold switching devices. (the compliment device code escapes me at the moment) IRFZ5902???

I used a pair of each (Pch and Nch) to build a H bridge for motor control.

I have a pair, used, but as far as known still perfectly functional.

 

[Perry Babin]

The IRLZ44N are the low-threshold.

I don't have anything on that amp. What is the gate resistor value?

Are there driver transistors (E-F pair) between the driver IC and the gate resistors?

What is thew driver IC?

 

[jan.didden]

The IRLZ44N are the low-threshold.

Ahh yes, it's been many years.

Jan

 

[Chopperbuilder]

The gate resistor value is 2k Ohms.


Best I can tell there are no transistors between the the driver IC and the gate resistors.


The driver IC is a SG3525A.

 

[Perry Babin]

As was stated, the Z44s are readily available and may be the simplest option.

If there are no driver transistors, you would read 0 ohms between the 3525 output pins and the gate resistors.

The gate resistors appear to be 100 ohms. Are you sure that they're 2k?

 

[neonarossa]

IRFZ44N datasheet
Equivalent transistors link...



MOSFET Cross-reference Search | Equivalent Transistors

Arrow has stock..
https://www.arrow.com/en/products/irfz44npbf/infineon-technologies-ag

 

[Chopperbuilder]

You are correct Perry, the gate resistors are 100 ohms. I have a hard time seeing the exact colors on the bands sometimes.



There is resistance between 3525 the output pins and gate resistors. This amp uses MPSA06's and MPSA56's.

 

[Chopperbuilder]

Thank you for the link, neonarossa.

 

[Perry Babin]

If you use the FETs you have on hand, you will need to use a lower value gate resistor. PPI commonly used 22 ohm. 47 ohm would be a good choice. Anything up to about 75 ohms should be OK. If there is enough deadtime programmed in, you may even be able to use the 100 ohm gate resistors.

 

[neonarossa]

Thank you for the link, neonarossa.

Very welcome.

 

[Chopperbuilder]

As was suggested, rather than do that I'll just get the IRFZ44's. Was hoping maybe I could use what I had on hand. Thank you Perry and every one for the advice and input.

 

[Chopperbuilder]

One last question concerning IRFZ44N. I was looking into ordering them but neither Mouser or Digi-key has them in stock. However they are both showing as having IRFZ44NPBF in stock. Not sure what the "PBF" stands for. Is there any difference between IRFZ44N and IRFZ44NPBF?

 

[Crazylogix]

The PBF stands for lead (PB) free (F). I always buy the IRFZ44V for rebuilding power supplies, it just looks to me the best performing one for the money. I think the letter at the end (N, V, or whatever) is maybe the revision, so possible that V is newer than N? Mouser and Digikey both have lots in stock.

 

[jkrokenberger]

I was advised to use IRFZ44 for PPI amps using the SG3525 with 100ohm gate resistors - this was for the M/AM series however. I was told the IRFZ44N's could cause issues.

PPI used different fets throughout production based on what they could get at the time. I have seen IRFZ48's with 100ohm gate resistors used in the A series as original equipment. They used different fets with the same drive circuits through production also. I imagine as long as the drive signals are clean in circuit it will be ok.

 

[Chopperbuilder]

I was wondering if the IRFZ44N's were factory or not. Actually not all the PS FETs are the same. Someone has been in this amp before and apparently made an attempt to repair it by replacing all the PS FETs. Two of the PS FET's they used are SMP25N06's.

 

[Chopperbuilder]

Crazylogix, thank you for explaining the "PBF". I had completely forgot able the periodic table, duh!