First generation of NV the SRAM module is published in the recent 20 years, NV the SRAM technology renews unceasingly, maintains with each kind of application synchronization development, simultaneously satisfies the new seal technology unceasingly aggregate demand.
Development and present situation
First generation of NV the SRAM module uses the great size DIP seal, as shown in Figure 1. This seal has certain altitude, because the battery and the RAM chip fold put during the DIP seal. The DIP seal’s merit lies in the component to be possible to insert the DIP plug, facilitates replaces and saves, or transfers to another from a print rotary-inversion. Although these merits are still until now useful, but comparatively, has the essential development surface to paste installs the technology, as well as the working voltage will become 3.3V by 5V.
Figure 1 uses DIP seal first generation of NV the SRAM module
Second generation of NV the SRAM module uses two piece of type plan - - PowerCap module (PCM), namely from welds printing plate’s base (to contain SRAM) as well as PowerCap (is also lithium battery directly, card buckle through shown in Figure 2 to fix on base) two parts composes. Compares with the DIP module, this kind of component has two principal advantages: They use the surface to paste the attire, and has the standard pin disposition. In other words, regardless of large capacity NV SRAM, its seal and the pin number are the same. Therefore, the designers may enlarge the system storage capacity, but does not need to worry that needs to change the PCB layout. The battery replaces is also very easy.
Figure 2 uses PowerCap module seal second generation of NV SRAM
The third generation is also newest NV the SRAM module, not only it has solved the problem which formerly the product existed, simultaneously increased multi-purpose. This kind of new NV SRAM is the monolithic BGA module, built-in may charge the lithium battery, as shown in Figure 3. Is the same with PCM, uses this kind of seal form all SRAM, regardless of its capacity size, the seal size and the pin disposition are the same. This kind of module uses the surface to paste the attire, and is the monolithic component. Therefore the design is firmer reliably, compares the previous generation component to be possible to withstand the stronger machinery vibration. Because the battery is may charge, therefore the data storage time’s concept had other meaning. Describes with an equivalent service life word is more appropriate, this kind of component equivalent service life may reach as high as for 200 years! This kind of module can withstand 230℃ the backflow welds the temperature, but provides the non-lead seal component may withstand 260℃ temperature.
Several kind of nonvolatile storage’s comparisons
SRAM was the data accessing and the memory has provided one fast and the reliable method. (For example battery) supplies power when by the system power source or other emergency power supplies, they have the non-volatility. Table 1 has given the nonvolatile storage storage technology good and bad points which several kinds assign.
In the NV SRAM battery regarding the data storage very important. Battery’s imperfect contact will affect the battery life enormously. Other factors, like the vibration, the humidity as well as the built-in battery cut electric circuit can reduce battery’s service life, simultaneously will also affect system’s overall reliability. These questions bring the most direct consequence is: The terminal customer replaced battery’s time-gap to be shorter, for example, needed to replace every year one time, but was not in 5~10 one time.
Figure 3 uses the one piece module seal third generation NV SRAM
Using
NV SRAM usually uses in requesting the maintenance number of times to be as far as possible few, carries on frequently reads/writes the operation, and the data storage speed is in the very important system. The numerical control milling machine is an example. The supposition machine is carrying on the mill operation the time sudden power failure. Stemming from the security concern, needs to withdraw the drill bit and to park it in a safety seat. Once on the electricity, the machine must remember stop work spot. Had NV the SRAM module, this duty is very easy to realize. The choice maintains the time should be equal to or be bigger than the time which the stored routine information needs to EEPROM. Before the data reads in EEPROM, still needed SRAM to act as the data buffer. Uses this plan, attaches part’s expense usually to surpass NV the SRAM module the cost, and the reliability is low.
In against distortion application, in the PoS terminal, the data record is specially important. Present’s intelligent terminal does not need to undergo the time-consuming long-distance server’s confirmation to be able to confirm the payment transaction. Because security data storage in terminal, therefore here depends upon the monolithic BGA module completely. The safe micro controller may deposit the key in the IC interior “the safe area”. However, still needed to take some extra measures, prevents to deposit in the SRAM enciphered data is read outside the micro controller and the decoding. At present can provide the protective measures were still insufficient to cope with these sly hackers. In view of this question, also has some solution, for example, Maxim/Dallas Semiconductor has promoted the BGA module which has custom-made, contains the safe micro controller, SRAM, the distortion examination electric circuit, as well as fixed time with control function.
Other must the data recording the application also to have the vehicle flight recorder, needs when has the collision should the data rapidly and deposits reliably in the memory. This time monolithic BGA once more becomes electing of the ideal by its reliability. The data distortion is a question similarly, but in the actual operation must solve this problem, may deposit the enciphered data to NV SRAM. Explains the enciphered data to be equal nearly in attacks the payment to trade the terminal, therefore is not worth regarding the hacker.
The abundant color machine request data recording, safeguards the customer right reliably. In this kind of application, the abundant color machine operator may turn on the machine, take out the battery, then made a false report that the data accident lost, therefore two piece of type PCM plan by no means ideal choice. May also each time open machine’s time will record reads in EEPROM, however like this will increase the extra cost and the order of complexity. In the BGA module’s battery cannot take out, therefore has solved this problem easily.
The high pressure fail-safe system needs to monitor the electrical network condition continuously, momentarily prepares to preserve the breakdown to have the time massive data. The equipment must guarantee, in the non-line maintenance technical personnel maintain in the situation uses at least for 10 years. As a result of fail safe installment usually by electrical network power supply, and in the BGA module’s battery cannot exhaust, therefore the BGA module is suitable for this kind of situation. This may realize the longer operating time. The new generation fail safe installment’s software design personnel only need select high density NV the SRAM module to be able to increase the SRAM storage capacity, does not need to change the existing board layout. Because all NV the SRAM module’s pin disposition is establishes well in advance, therefore the SRAM density increases time, only need be more address wire which “connectionless” the (NC) pin becomes needs then.
Conclusion
NV the SRAM module not only may fast and the reliable stored datum, moreover also very much has the competitive power in the seal technology aspect. These components are suitable in need the security data storage as well as do not need on-site maintenance nearly the situation.
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