Reading RAM - Stuff you shouldn't know

Ever wonder if that RAM you bought is really what you wanted? Unless the OEM is nice enough to put an inventory sticker on the ram stick with 64, 32, 100, or 133 cryptically in there somewhere, you wouldn't have a clue what it was you were holding. The same goes for that sick of RAM that was hiding behind the couch - what speed is it? How then do you decipher the codes printed on each chip? Well, step one is to go to the manufacturers website and hope they are web-savy enough to have put up decent documentation. I looked around trying to find out what one stick of RAM I have is but wasn't able to find any info on it. Strangely enough Hyundai (Korean Car maker to most of us) has such a section on their website. Listed are hundreds of Adobe PDF's that explain every single bit of code and tell you way more then any normal human should know about their RAM. Remember HY57V651620B TC-75, cause we're about to explain what the heck it actually means. A) B) C) D) E) F) G) H) I)   J) K) HY 57 V 65 16 2 0 B / TC 75 HY 5X X XXX XX X X X X - XX XX A) Hyundai: HY Memory products B) Product Group: 57 SDRAM C) Processor & P/S V CMOS, 3.3V D) Density & Refresh 65 64M bits, 4k Ref E) Data width 16 x16 F) Bank 2 4 Banks G) Interface 0 LVTTL H) Die generation B 3rd Generation I) Power Consumption / Normal Power j) Package TC 400mil TSOP-II k) Speed 75 7.5 ns (133MHz) See the PDF with all the info So now the cryptic message makes some sense, and we see our stick of RAM is pretty dang good. 7.5ns, 3rd die generation and running at 133Mhz just like we expected. While this isn't a very useful exercise if you already know what you have, it can be very useful if you haven't a clue what a particular stick of RAM is.

While looking around their site I was able to dig up even more info on my "can I have 64megs of 133Mhz RAM, please". Again this all falls under the category of stuff no human should really know, but its still interesting none the less...

The Hyundai HY57V651620B is a 67,108,864-bit CMOS Synchronous DRAM, ideally suited for the main memory applications which require large memory density and high bandwidth. HY57V651620B is organized as 4banks of 1,048,576x16. HY57V651620B is offering fully synchronous operation referenced to a positive edge of the clock. All inputs and outputs are synchronized with the rising edge of the clock input. The data paths are internally pipelined to achieve very high bandwidth. All input and output voltage levels are compatible with LVTTL. Programmable options include the length of pipeline (Read latency of 2 or 3), the number of consecutive read or write cycles initiated by a single control command (Burst length of 1,2,4,8 or Full page), and the burst count sequence(sequential or interleave). A burst of read or write cycles in progress can be terminated by a burst terminate command or can be interrupted and replaced by a new burst read or write command on any cycle. (This pipelined design is not restricted by a `2N` rule.)

FEATURES

• Single 3.3±0.3V power supply
• All device pins are compatible with LVTTL interface
• JEDEC standard 400mil 54pin TSOP-II with 0.8mm of pin pitch
• All inputs and outputs referenced to positive edge of system clock
• Data mask function by UDQM or LDQM
• Internal four banks operation
• Auto refresh and self refresh
• 4096 refresh cycles / 64ms
• Programmable Burst Length and Burst Type
  - 1, 2, 4, 8 or Full page for Sequential Burst
  - 1, 2, 4 or 8 for Interleave Burst
• Programmable CAS Latency ; 2, 3 Clocks

RAMfinder

We've been getting a few requests to look for info on specific strips of RAM, so I'm putting up these little guys  here to take you to the general area where information is available on each particular brand. Check out the links and read your Ram!

NCP RAM - No docs ??	NEC RAM	TOSHIBA RAM
MOSEL RAM	HYUNDAI RAM	TEXAS INSTRUMENTS RAM
J.tec RAM	Micron RAM	OKI RAM
Apacer RAM	Mitsubishi RAM	LGSemicon RAM
	Nanya	South Land Micro (SMT)
Fujitsu RAM	Hitachi	Elite
WINBOUND RAM	SAMSUNG RAM