LBRC

2007.10.28, 03:51 AM

Mentioned these in a MA-010 FET thread but decided they rate their own thread after spending a day playing with them.

On paper they’re very nice with a -7.3 amp continuous drain current for the P-channel and a total P+N on-state resistance of 54.5mΩ at 4.5V, for comparison the Vishay 4562 lists a -6.2 amp continuous drain current and a total P+N on-state resistance of 58mΩ at 4.5V.

Data Sheet Link: http://www.fairchildsemi.com/ds/FD/FDS8858CZ.pdf

Max rated continuous drain current at 25° C:

N-channel 8.6 amps

P-channel -7.3 amps

On-State Resistance:

N-Channel

• Max rDS(on) = 20mΩ at VGS = 4.5V, ID = 7.3A

P-Channel

• Max rDS(on) = 34.5mΩ at VGS = -4.5V, ID = -5.6A

Of course what the manufacturer lists on the data sheet and how they actually hold up in a Mini-Z is not always the same thing but so far for me they seem to be living up to the specks. First I put a 1x1 set in an old MR-01 and after tentatively playing around with different motors I got brave enough to pop in an Atomic T2 with a 6 then eventually 7 tooth pinion to run some wall bashing 50 lap sets on a 2xWide-L RCP track. Ran out of courage at the 7 tooth pinion though, even with a listed 7.3 amps I thought anything more would be asking for a miracle, besides a T2 in a MR-01 on a small track is bit more than I can handle. The question is how long will they last as a 1x1 with a motor as hot as the T2? My guess is that even though it has now gone through 4 NiMH battery sets and nearly 400 laps it’s just plain lucky to be alive.

After the MR-01 I put a 2x2 in a MA-010 with one of the blue MZWS BB practice motors (I believe it’s a 47 turn); noticeable power increase over the 3010’s with the same motor and batteries, very snappy throttle response but still quite linear, just the way I like it, and with an estimated/rated 14.6 amps of current handling ability even in an AWD the 2x2 should be able to handle just about any motor I'd want.

http://lbspd.com/v-web/gallery/albums/album164/FDS8858CZ_x_2.jpg

The Big Question:

Do I like them more than the 4562’s? Don’t know yet only time will tell, maybe. What I can say without a doubt is that I like the price, 82 cents each or $54.60 for 100 from Digi-Key, and if your looking for FETs the 8858’s are definitely worth considering.

On paper they’re very nice with a -7.3 amp continuous drain current for the P-channel and a total P+N on-state resistance of 54.5mΩ at 4.5V, for comparison the Vishay 4562 lists a -6.2 amp continuous drain current and a total P+N on-state resistance of 58mΩ at 4.5V.

Data Sheet Link: http://www.fairchildsemi.com/ds/FD/FDS8858CZ.pdf

Max rated continuous drain current at 25° C:

N-channel 8.6 amps

P-channel -7.3 amps

On-State Resistance:

N-Channel

• Max rDS(on) = 20mΩ at VGS = 4.5V, ID = 7.3A

P-Channel

• Max rDS(on) = 34.5mΩ at VGS = -4.5V, ID = -5.6A

Of course what the manufacturer lists on the data sheet and how they actually hold up in a Mini-Z is not always the same thing but so far for me they seem to be living up to the specks. First I put a 1x1 set in an old MR-01 and after tentatively playing around with different motors I got brave enough to pop in an Atomic T2 with a 6 then eventually 7 tooth pinion to run some wall bashing 50 lap sets on a 2xWide-L RCP track. Ran out of courage at the 7 tooth pinion though, even with a listed 7.3 amps I thought anything more would be asking for a miracle, besides a T2 in a MR-01 on a small track is bit more than I can handle. The question is how long will they last as a 1x1 with a motor as hot as the T2? My guess is that even though it has now gone through 4 NiMH battery sets and nearly 400 laps it’s just plain lucky to be alive.

After the MR-01 I put a 2x2 in a MA-010 with one of the blue MZWS BB practice motors (I believe it’s a 47 turn); noticeable power increase over the 3010’s with the same motor and batteries, very snappy throttle response but still quite linear, just the way I like it, and with an estimated/rated 14.6 amps of current handling ability even in an AWD the 2x2 should be able to handle just about any motor I'd want.

http://lbspd.com/v-web/gallery/albums/album164/FDS8858CZ_x_2.jpg

The Big Question:

Do I like them more than the 4562’s? Don’t know yet only time will tell, maybe. What I can say without a doubt is that I like the price, 82 cents each or $54.60 for 100 from Digi-Key, and if your looking for FETs the 8858’s are definitely worth considering.