SILF33 or SILF333 micro datasheet

I've exhausted my efforts on google trying to identify this device.

It appears to be a microprocessor and is quite likely faulty ... but a datasheet will help me draw out the cct.

Does anyone recognise it please.

The label shows

SIL
F33
BORAW
1731+

One from a second device is labeled

SIL
F333
BOLNH
1704+

Thank you.

A version of the small form factor micro controller w/built-in flash made by Silicone Labs . May contain custom programming.

Wow, thank you thank you vtech

Yes, I have no doubt it has custom programming as it's the only chip on the board ... along with a 3.3v regulator and a couple of mosfet switches.

The boards have been wet with quite minor corrosion (on one anyway) ... but neither have any clock signal or other signs of life. I assume the micros are dead ... but at least now I can check properly.

Thank you again, much appreciated.

The new photo shows the crook board at the top ... the other 4 are earlier versions of the same device which seem bulletproof. They are heavily coated in a flowable silicone ... which protects them well.

But they are something like $180 each ... hence the desire to keep them going.