Help identifying chip on Sega Nomad

Hi

Could someone please identify the following chip on my Sega Nomad, I have another Nomad and on this system this chip looks to have blown at some point. I'm getting readings of up to 20v from some of the pins, whereas on the working chip the reading are around 2.3v.

It's labelled as 5C57 or it could be 5C51, listed as part TR202. I've looked for Nomad schematics but haven't had any joy so far. What could I replace this part with?

Current symptoms of the system are, replaced 5v voltage regulator and system is getting 5v where it should be, but when I turn it on connected to TV there is no activity apart from a whining sound. The built in LCD is missing so cant test that.

 

Looks to be a surface mount transistor. Can't find that one exactly though, but this may help:
https://www.sos.sk/pdf/SMD_Catalog.pdf