AOP605 Replacement

[Alup]

I am in need of about 40 AOP605 Mosfets due to the fact that they have been discontinued and i do not trust ebay. I have been searching for a compatible replacement for them. I have not found one that is a 1:1 replacement but i did find one that "Should" work only problem is that it is SMD not Throughhole.

My question is Would this part: IRF7389TRPBF be compatible with this part AOP605 If so then i can just eaither do 1 of 2 things. 1. I could buy a SMD to Throughhole adapter and use that. or 2. I could just mount it on the bottom of the board upside down. The pins are labeled different on the spec sheets but they are electrically the same.

What do you guys think? Please let me know.

The reason i posted this in this section is because this is a very common "problem" chip on the DAC-19M008 power board that is used in Multiple monitor brands.

Also this might come in handy if anyone in the future comes across this post. DAC-19M008 Schematic/Parts List

[retiredcaps]

Re: AOP605 Replacement For DAC-19M008 Power Board

I am in need of about 40 AOP605 Mosfets due to the fact that they have been discontinued and i do not trust ebay.

Yes, ebay can be full of fake or low quality parts, but I can't recall over the last 2.5 years of anyone having a bad experience with the above chip when procured from an ebay seller.

Buyers may not like the long wait time, but the actual part has not been problematic.

[Alup]

Re: AOP605 Replacement

But will the above chip work? I would like to know because i have about 50 of these viewsonic monitors that have this power board in them.

[budm]

Re: AOP605 Replacement

How about using discrete MOSFETs in stead?
AOP605 spec:
n-channel p-channel
VDS (V) = 30V -30V
ID = 7.5A (VGS = 10V) -6.6A (VGS = -10V)
RDS(ON)
< 28mΩ (VGS = 10V) < 35mΩ (VGS = -10V)
< 43mΩ (VGS = 4.5V) < 58mΩ (VGS = -4.5V)


Try contacting AO to see what they suggest?


ALPHA & OMEGA Semiconductor, Inc
495 Mercury Drive
Sunnyvale, CA 94085
U.S.
Tel: (408) 830-9742

[Alup]

Re: AOP605 Replacement

I tried contacting them and they never responded this was over a week ago. Will the Surface mount one work? Also i found this Mosfet as well that will 100% work but its just as hard to source. AP4511GD

[rievax_60]

Re: AOP605 Replacement

Its available from UTSOURCE and many Aliexpress sellers.
So far all 9 orders via Aliexpress have arrived for me.

[Alup]

Re: AOP605 Replacement

Its available from UTSOURCE and many Aliexpress sellers.
So far all 9 orders via Aliexpress have arrived for me.

Thats nice and all but will the SMD version work?

[rievax_60]

Re: AOP605 Replacement

Thats nice and all but will the SMD version work?

I dont know. Many are DIP.

[rievax_60]

Re: AOP605 Replacement

If you search for AOP605 on UTSOURCE or Aliexpress, you will find plenty.

[Alup]

Re: AOP605 Replacement

thank you but I'm looking for a replacement i do not want to use the AOP605 that was the entire reason for my post. I want to use an updated chip that can be bought in mass quantities from sites like mouser/digikey. The AOP605 had heat issues and the SMD chip that i posted in the OP does not have that issue. Please let me know if this is a reasonable replacement. Converting the SMD to through hole is not hard at all with the adapter, and it would raise it off the board so that if it does indeed get hot it will not burn the board.

[budm]

Re: AOP605 Replacement

Can you explain about the heat issue? The AOP605 and the IRF7389TRPBF has the same power rating, both of them do need a way to transfer the heat, on the surface mount, they will lay out big copper plain on the D pins to dissipate the heat.
The IRF should work since it has the same Rdson. The higher the Rdson the more heat it will generate.
One thing to be careful about using long leads on the adapter board connection, all leads have inductance since you are switching at 60~100Khz, need to keep the lead as short as possible.

[Alup]

Re: AOP605 Replacement

well, they tried to but i guess it was not enough copper on the trace because most of the boards i have are like dark brown around the chips. I thought about using some tiny heatsinks on top of them but if i can go the SMD route and bottom mount it then i will just use the rf shield as the heatsink. since no one will directly answer the question then i will just buy a few and test them out. they should work from what im reading on the spec sheets. I will post an update when i know if they are a suitable replacement.

[budm]

Re: AOP605 Replacement

The reason it is running hot is due to poor DC filtering of the power supply, if the DC filter caps are not filtering properly due to high ESR and lower capacitance, the high frequency AC ripple will be riding through to the inverter circuits and modulate the high frequency switching of the inverter circuits (the frequency of the SMPS and the inverter PWM are not the same, both signals will add and subtract to produce the side band frequencies, so the switching frequency will be off from the original design requirement which will cause the transformers and the switching devices to get hot. You have have thermal probe, you can check the temperature of the transformers and the IC of the unit with bad caps and the one with good caps.
As I indicate before that both IC has the same Rdson, just think of it as the resistor that will have to dissipate the power, since they are the same, the power dissipation will be the same.

[rievax_60]

Re: AOP605 Replacement

well, they tried to but i guess it was not enough copper on the trace because most of the boards i have are like dark brown around the chips. I thought about using some tiny heatsinks on top of them but if i can go the SMD route and bottom mount it then i will just use the rf shield as the heatsink. since no one will directly answer the question then i will just buy a few and test them out. they should work from what im reading on the spec sheets. I will post an update when i know if they are a suitable replacement.

I just noticed that the IRF7389TRPBF has all of the Drains joined in the package. Will this be a problem?
I repaired a Panasonic TV a while back. Its lamp inverter MOSFETs failed because of a high ESR rail capacitor.

EDIT: On second thought, the Drains are likely to be joined in the circuit anyway. OK, just noticed they are joined in the schematic.

[budm]

Re: AOP605 Replacement

They are N and P channel set up for the half bridge (1 IC) or full bridge drive setup (2 IC).

[rievax_60]

Re: AOP605 Replacement

I am curious about the function of Q100 in the power supply. Its job seems to be to put a load on the 19v rail if it rises.
Have to wonder what would happen without it.

[budm]

Re: AOP605 Replacement

That Q100 is used for putting the R100 (300 Ohms) load on the output when the voltage is high enough at 19.6V (Vzener of 19V + Vbe 0.6v of Q100) to turn on the Zener Diode ZD100 (19V) and Q100 when inverter is not on to draw enough current to make the outout drops voltage to drop down below 19.6V. It is like having the load connected automatically when there is no load from the inverter.