Finding mosfet id or equivalent !

[420homestead]

as stated trying to find part or equivalent to the one's that are burnt for repair i see part # 21GMAA and cant find it anywhere

 

[Papabravo]

Why would MOSFETs be in 8-pin packages? You do know that the markings on SMD parts are shorthand codes for the actual part number – right?

 

[Tony Stewart]

It seems too long for an SMD Code and 1 has a space .. try matching dimensions to find case type and search by function like .. is it a half-bridge for 3 phase?

 

[420homestead]

not sure on the half-bridge or 3 phase .. its the mosfet drivers off a 1s driven dual motor rx/esc for hobby grade ultra micro airplane.

so i have no idea of the values needed to find a acceptable replacement .. is there any way for me to test impedance/ resistance what ever needed for a more educated person in this field of expertise to find a solution .. i have multimeter and such just tell me what setting and what to touch to messure for datta needed to figure out an equivalent?

 

[For The Popcorn]

Why would MOSFETs be in 8-pin packages?

I guess that's a question for the manufacturers, since many MOSFETs are available in soic-8 packages.

 

[Papabravo]

I guess that's a question for the manufacturers, since many MOSFETs are available in soic-8 packages.

I did not know that. It seems like a suboptimal choice for certain power levels.

 

[Tony Stewart]

Measure the motor DCR and I would expect RdsOn around 5% of that.

If bidirectional then it is a full bridge, otherwise half bridge

e.g. https://www.digikey.ca/en/products/detail/monolithic-power-systems-inc/MP6610GJ-Z/15992058

or keep looking ... https://www.digikey.ca/en/products/...?s=N4IgTCBcDaIBYEMA2AzABAIwE4EsAmA5gKYgC6AvkA

 

[rjenkinsgb]

I'd guess they are either dual MOSFETs, or "Half bridge" power driver ICs.


You need to try and trace the connections to the devices, to determine the pinout as far as possible.

eg. Which pins(s) are ground (0V, negative battery) and which are battery +?
Which connect to the output connector?

 

[420homestead]

Measure the motor DCR and I would expect RdsOn around 5% of that.

If bidirectional then it is a full bridge, otherwise half bridge

e.g. https://www.digikey.ca/en/products/detail/monolithic-power-systems-inc/MP6610GJ-Z/15992058

or keep looking ... https://www.digikey.ca/en/products/...?s=N4IgTCBcDaIBYEMA2AzABAIwE4EsAmA5gKYgC6AvkA

Measure motor DCR I guess that's DC resistance that you're telling me.... and what is RDSpn what's that stand for the resistance... Okay once I have that what's that going to tell me as per after I get this measurements CR and then five find a 5% of whatever that is and then we'll kind of measurements do I do for to find House of mosfet measured

 

[420homestead]

I'd guess they are either dual MOSFETs, or "Half bridge" power driver ICs.


You need to try and trace the connections to the devices, to determine the pinout as far as possible.

eg. Which pins(s) are ground (0V, negative battery) and which are battery +?
Which connect to the output connector?

Not sure I'll what you mean it's the dual motor so there's a two sets so it's a dual ESC.../. It's on a 1S- 3.7v small plane with a dual motors

 

[Tony Stewart]

FET on resistance is RdsOn

 

[420homestead]

Well my experience you know I know how to replace a solder loan component and usually I don't have much trouble finding it off the part number of the skewer at least from that I can usually get the values to find something comparable but this thing not even close that's why I need to kind of know how to testing formulate kind of what I'm looking for but I'm thinking I'm about there so I get that DC resistance and then take 5% or whatever for the flow like the other guy said and kind of come back from there I'll have me a multimeter this afternoon