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Chip part numbers do not always follow any pattern, manufacturers tend to form a naming style but this is not always true. Often it is difficult to describe the patterns they are so random, but as you become familiar with IC part #, You begin to see the patterns more easily. This page lists some patterns and techniques for deciphering the part numbers; however, there are no rules, so these hints will not work in all cases.

Before looking at the part number

There is a lot you can learn from a chip before even looking at the part number.

Manufacturer Identification

Manufacturers tend to focus on certain sectors of the IC business, and avoid other sectors. So identifying the manufacturer can bring you a great deal closer to its function.

Here is a list of hundreds of manufacturers and what they specialize in:

To identify the manufacturer See: Guide to IC manufacturer logos

If there is no logo, the manufacturer can often be found in the part number itself. See the Manufacturer Prefixes Section

Chip Package Identification

The chip package can also give you hits as to its function.

Chip Package styles before 1990
  • CPUs & FPUs: mostly CDIPs, higher end CPUs used PGAs.
    • Usually removable
  • UV EPROMs: Always CerDIP with a sticker covering a window to the die.
  • Basic Logic: Usually Ceramic SDIPs
  • Resistor Chains: yellow or orange(not black) SIPs, or SDIPs
Chips after 1995
  • CPUs & FPUs: PGAs
  • MCUs: PDIP,
  • CPU & MCUs support chips:PDIP, SOIC
  • Basic Logic: plastic SIPs, SOIC
Chips after 2000

Identify by Application

If you know the function of the board your chip is on then you know what basic functions chips on the board would have to perform.

  • A computer motherboard would generally have a CPU, maybe a FPU, a bios chip, cache memory, and a few bus controllers.

Narrowing down the different functions of each chip on the board can help you guess your chips function.

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

Part number generally follows the following formats

  • [alpha characters for manufacturer][more generic part #][Alpha chars for package, revision, etc.]
    for example Am2901ADC, for [AMD][part 2901][revision A,D=ceramic,C=?]
    or SY6502, for [Synertek][part 6502]
  • Another common part number style is [pkg type][generic part#][speed,rev.,...]
    for example A80486DX-16, for [A=ceramic pin grid array][part 80486, or more commonly called 486][Rev. DX, speed 16 MHz]
    or P8080A, for [plastic dip package][part 8080][rev. A]

Manufacturer Prefixes

Below is a table of common manufacturers part number prefixes, this are not always true, but most of the time they are.

Common Manufacturer by Part # Prefixes
Am - AMD LI,L - LSI Z - Zilog
SY - Synertek T - TI MC - Motorola
T - Toshiba Cx - Cyrix HD - Hitachi
SCN - Signetics Nx - NexGen WD - Western Design Center
Max - Maxim AD - Analog Devices TX,TMS - Texas instruments

Common IC Families

The quickest way to identify the chip is to identify that it is a member of an IC family. By identifying the family you find the function without worry about prefixes and suffixes

  • 80x86
    • Examples: 8086, 80186,80286,80386,80486
    • Full part #: D8086, A80386DX-16
  • 80xx based MCUs
    • Examples: 8031, 8051, 8049, 8048, 80151, 80251
    • Full part #: N80C31BH, S-80C31, P8048H
  • 7400 TTL Logic Series
    • Follows the format, [various alpha char][74][type][2-3 digits for the distinct function][Various alpha char]
      • What to look for is 74[type][2-3 digits]
    • there are many types of chips for each function, that describe speed, power, technology, voltage,....
    • The function number, called the part pumber with the 74 in front, goes from 00 to 882, There are a few with 4 digits but they are uncommon
    • Examples:74LS02, 74HC14
    • Full Part #'s: CD74AC04E, SN74AUC14RGYR
  • 4000 CMOS Logic
    • 4000 to 4585
  • MC68xx MC68xxx
    • Motorola 6800 and 68000 CPUs and there support chips
    • Example: MC68HC12
  • PAL Programmable array logic
    • Not really a family, but usually have PAL in the name or one the chip

Searching the part number

Usually searching a part number results in hundreds of useless pages with large lists of part numbers, and no information.

IC datasheet archives

These are some reputable datasheet searches, there are a lot of fake commercial ones.

This search box will search Google while filtering out most of the useless pages:">

or click the Link below and add you part number to the beginning of the search box

Common Families

Specific Companies Nomenclature

Example of Identifying chips in a circuit boards

  1. Board's function Identification

1: Board's function Identification



Assuming we had no idea where the board came from this board's function is easy to identify. W could look up the part # on google, but often that information is long lost so be have to use other methods. i From a glance at the board there are several identifiable markings.

  • A: Large chip in a pin grid array package
    generally large PGAs are CPUs, but we could also search google for Intel i960 and find that it is a CPU for servers or high end workstations.
  • B: Simm chip sockets
    These are obviously for RAM
  • C: standard computer plugs
    clearly identifying it as a computer
  • D: floppy drive
    and computer often have floppy drive ports

From these features we know that it is a server or high end workstation motherboard.

Chip functions

Guesses in chips functions with out looking up the part number

I have divided the board up into three section to make in easier to describe.

Section 1


  • A: the circuit in the is obviously a DC-DC converter, because it is a compact, and separate circuit consisting of capacitors inductors/transformers, large transistors and diodes. It is also likely that the chips around it are drivers for the transistor, compensator or otherwise involved in the converter.
a DC-DC converter is usually near the power input or the CPU, but it is not on this board.
  • B: These chips are some sort of resistor arrays. Colored DIPs, SIPs, or SOICs are always resistor arrays. They are often near output ports or LED arrays.
  • C: These IC are most likely drivers, buffers, for the output ports to increase signal integrity. This is shown by their closeness to the output ports.
  • D: The Bt chip says RAMDAC. this is often involved in video monitors. Bt makes RAMDAC video processors, and the closeness to the VGA port further confirms this.
  • E: This chip is ambiguous, and will most likely have to be looked up. Search on a search engine for HP and one of the lines of Alphanumeric. This chip is even hard to decipher which line is the part number, but one will be. However data about this chip may be proprietary or lost in time.
  • F: These chips could be a number of things. Since they are all the same and to small to be memory they are probably drivers or buffers. SOICs often have these simply functions and if they are these functions then the part numbers will usually be easy for find their datasheets.
  • G: These chips functions are hard to say. they may be signal drivers for the ethernet plugs. But their functions will probably have to be looked up.
  • H: This chip has a frequency on it, so it is an oscillator, clock, crystal or resonator. Any of these functions are used to make a clock.

Section 2


See Also

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