For computing devices today, power is a critical issue. Analog or Mix-mode IC designers are no longer just making power converting chips like AC-DCs and DC-DCs. Instead, they must deal with whole power transfer and management systems. The power systems must provide stable, efficient, and intelligent power supplies. Furthermore, the footprint of the power system may need to be compact enough to fit inside a portable device.
The most popular countermeasure for these power management systems is producing power-related chips on a BCD process platform; the platform must have reliable embedded non-volatile memory solutions. Some predictions indicated that the average gate densities in a power controller are increasing from several kilo gates/mm2 to hundreds of kilo gates/mm2 and may achieve millions of gates/mm2 in the foreseeable future. In other words, the foundry nodes of BCD platforms are migrating from traditional 180nm/130nm to 90nm and even 65/55nm.
eMemory, a worldwide leading eNVM IP company, continuously develops OTP (One-time programmable) and MTP (Multi-time programmable) solutions for these BCD platforms to fulfill the requirements of power IC design houses. MTP will grow significantly in power-related applications because the alternative, eFlash (embedded flash), is expensive on BCD platforms. Compared to eFlash (which requires over ten additional masks), MTP needs no additional masks and maintains a performance good enough to cope with the tasks in the power controllers.
For example, wireless chargers and USB-PD controllers are typical cases that require eNVM on the BCD platform. Embedded flash is too expensive for these consumer-grade products, while entry-level solutions like eFuse are not good enough in density and re-programmability. Both OTP and MTP are more suitable candidates than eFuse and eFlash in these applications. Moreover, these power management technologies are evolving and expanding into numerous application fields, e.g., smartphone, laptop, TWS, smartwatch, smart meter, electric vehicles...etc. There will always be new inventions that require different power transfer capabilities, standards, protocols, and more. Therefore, they may have various design considerations requiring more flexible IP solutions.
eMemory provides OTP and different types of MTP for design flexibility to fulfill the many different needs of the evolving power management market. For example, since IP size is very critical, eMemory has several approaches to reduce IP size. The gen-2 NeoMTP adds two extra masks to adjust well implant (without violating foundries’ well rules and require no additional thermal budgets) to reduce cell size. Smaller cell size also leads to less parasitic capacitances, thus relieving the loading of peripheral memory driving circuits and reducing the IP size. NeoMTP gen-2 is particularly suitable for ICs that are relatively small in chip size; therefore, the benefit of lowering IP size is significant.
Another benefit of MTP is providing less re-programmable endurance cycles. Generally speaking, endurance cycles of memory is an important feature of non-volatile memories. However, in many power-related applications, the embedded MTP won’t be re-programmed repeatedly because the information in the MTP only needs to be altered or updated during the testing phase and won’t be changed after shipping. Since there’s no need for more endurance cycles, the pumping/sensing/erase verification circuits of the MTP peripheral can be simplified and further optimize the IP size.
Table 1. Reference gen2 and few times MTP spec. on 130nm BCD
Recently, eMemory’s NeoMTP has been qualified on TSMC 90nm BCD for future power-related products. 90nm BCD is expected to be a popular node for applications like smartphone sub-PMIC, wireless charger, adaptor, audio amplifier...etc. In addition, NeoMTP on TSMC’s 90nm BCD can support up to 512Kbits density which is enough to store firmware codes, parameters, and configurations of most of these controllers.
Table 2. NeoMTP reference spec. at TSMC 90nm BCD
NeoMTP has superior reliability than other mechanisms like BBHH (Band to Band Hot Hole) due to its erase mechanism of FN tunneling. FN tunneling causes less oxide degradation, less erase current, and does not require process tuning. However, NeoMTP still attains better high-temperature operation performance, making it inherently better in auto-grade applications. Therefore, NeoMTP is suitable for automotive applications, containing plenty of reliable MCUs/ECUs and complex power/battery management systems. MTP is also AEC-Q100 grade 1 (125oC) and grade 0 (150oC) qualified, with additional ISO-26262 functional safety certification in progress and expected to pass this year.
eMemory keeps expanding MTP availabilities on BCD platforms in worldwide foundries for the growing market and various applications. Widespread availability is crucial, especially today since IC demand is strong and foundry capacities are tight. In addition to TSMC, eMemory is also working with SMIC and HHgrace to implement MTP on the 90nm BCD process for China’s growing power management market. eMemory is currently developing NeoMTP on the even more advanced 65nm BCD platform with the Israel-based foundry – Tower Semiconductor.
Table 3. NeoMTP availability of worldwide BCD platforms
Most importantly, compared to other eNVM solution providers, eMemory is the most dedicated and experienced company focused on eNVM IP development. eMemory has the best understanding of the foundry eco-system, plenty of worldwide fabless company networks, hundreds of engineers and experts cultivated in the eNVM field for years, and more resources than competitors to customize IP and respond to engineering issues just-in-time. As the power applications and BCD technology evolve, eMemory is confident in being the best partner for customers to launch more cutting-edge designs and products.
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