About Memory

Identification of memory:
1. Look memory chips, legible, do not rub your fingers blurred, label is correct. But now high-level of fraud, printing methods also improve a lot., About the authenticity of the particles,need us further relevant information.

 2. Pinout memory chips are neat, not crooked, the Welding spot must be smooth and mellow,To discharge the possibility of manual welding.

3. Except the memory chips, the next slightly larger device is SPD, which is stored in memory EEROM of various related information, because some motherboards do not need to read the SPD and also can be automatically configured, so it is possible to provide for fraud. The SPD is Essential devices, so some JS will weld an empty SPD, you can check Solder joint degree rounded device, and make Rough judgment, and also can use other software measurement to check.

 4. The capacitor is also a very important device, poor quality of the memory have less capacitor. In general, the capacitance , the better, it can provide a stable power supply, will optimize the signal quality. If you find the memory less than three capacitors, this is a problem of memory, standard is also suitable.forother brand memory.

 5.DDR memory has a reference level (Vref), Gold finger pin No. 1 to stabilize this signal, it is very importan for DDR memory, so try to make it without interference. It’s better to pick a special decoupling capacitor near Gold finger pin No. 1, Each particle corresponding Vref pin have to pick up a decoupling capacitor, Poor quality memory may be no such reference level of decoupling capacitors.

 6.Remaining device is the resistance, and four with the resistance called exclusion. The key is to use the data lines and differential clock signals match, 64-bit data bus, it must have 64 resistance (or 16 exclusion) on memory,the role of the resistance of the signal is less volatile, improve noisemargin, but generally do not have this resistance to work, I often see that some memory of the resistance of the weld where the direct short, so you can save several cents per memory ah! For differential termination resistor, too,are able to work without it, that would be a lot worse quality. For the SDR is typically 10 ohm series resistance, it is 22 ohms for the DDR, and the matching resistance differential clock signal of 120 ohms.

 7. Device is finished, now talk about PCB, which is the circuit board of memory. Look at the bright color or not, how smooth feeling of hand touch.

8. From industry to formulate standard PC100 of SDRAM. from the beginning of memory requires at least 6-layer structure, 6 laminates can ensure a more stable power supply, better signal quality, less electromagnetic radiation, the physical and mechanical properties will be optimized a lot.