Identifying an unknown chip on a PCB

Question

I'm working on reverse engineering a PCB (no documentation by manufacturer). I've identified all the other chips on this board but this one refuses to give up any google-able info. Are there any resources that can help me identify what kind of chip this is?

      ______________
D1 --|O    ATH 330  |--?
D2 --|              |--Vss
Vss--|     50?L  8  |--D4
GND--|     3U49758  |--D5
      --------------

D1, D2, D3 and D4 pins are connected to a 5x2 grid of test points which I've soldered a header into. Vss is connected to the Vss of a PIC32MX695F512H microcontroller.

Let me know if I can provide additional info to assist this process.

Answer 1

The markings look like an Atmel part (it starts with "AT", which is common for Atmel parts). Given the size of the chip and context which you provided, I figured it was probably a serial EEPROM. Looking through Atmel's serial EEPROM datahsheets, your mystery chip is almost certainly an Atmel AT25128B-SSHL SPI EEPROM, which matches your chip's product markings and pinout.

According to the AT25128B datasheet, the first line should be ATHXXX, where XXX is a three digit date code. In your case, "ATH330" means it was made in the 30th week of 2013.

The second line contains the product's truncated part number (truncated part numbers are used when the entire part number is too long to fit on the package) and country of assembly. The truncated part number for the AT25128B is "5DBL", which from the picture looks reasonably like what is printed on your chip, and the trailing "8" identifies the country of assembly (I don't know what country "8" corresponds to, but its probably somewhere in Asia :)).

The last line is the Atmel lot number.

Answer 2

You can try this:-

All Data Sheet

(sorry this won't allow me to post more than 2 links, you can refer wikia page for other sites like All Data Sheet)

Identifying and deciphering the part number Deciphering a chip's part number is a very ambitious process and most of the time, typing the whole part number in a search engine gets you nowhere.

General Format In general computer chips or integrated circuits follow the following format

Line 1: Manufacturer's Name

Line 2: Part number

Line 3: date code, and other coded information Less often lines 2 and 3 are reversed

Quoted From Wikia

Searching via part number is your best bet, if you still don't find it I will help you find it. good luck.

Answer 3

Googling for the 49758 gives some results: Description Datasheet prefix 3U probably means that its a 3V version of the part

Answer 4

Are there any other similar chips on board? If not, it could be an SPI or even i2c flash of some kind, maybe used for, perhaps, a MAC address. The test points would then be used to write the hypothetical MAC address; but you would then expect to see at least some of those same lines connected to the rest of the circuit

So what you could try is to lookup the datasheets of other common 8-pin flash chips and see if any of the pinouts line up with what you have observed.