From the external interface,PSRAM is as simple as traditional SRAM-you only need to give an address,issue a read or write command,and you can access data directly,and you don't need to add a memory controller to worry about refresh timing like using DRAM.If we go deep into the internal research,we will find that PSRAM is actually a DRAM design.The memory cell of PSRAM adopts 1T1C structure(one transistor plus one capacitor),and the density is much higher than the 6T cell of traditional SRAM.It is precisely because of this"internal dynamic and external static"characteristic that it is called"pseudo"static memory.PSRAM does not completely replace SRAM or DRAM,but provides an intermediate option.If your project needs to expand memory and want to keep the interface simple,this kind of pseudo static memory is a good substitute.
 

Take the EMI brand PSRAM chip EMI116NA16LM-70I represented by Yingshang as an example.This memory adopts the organization mode of 1M x 16,with a total capacity of 16Mb.PSRAM supports a wide voltage range of 2.7V to 3.3V,with a response speed of 60 to 70 nanoseconds,and is packaged in 48BGA.These parameters mean that it can achieve a good balance between power consumption and performance,and it is suitable for industrial control,consumer electronics,communication modules and other scenes that require stability and volume.
 

Compared with traditional SRAM,PSRAM has smaller chip area and lower cost under the same capacity.Compared with DRAM,it saves complicated memory control logic.In other words,it is stuck in the balance between"large capacity"and"ease of use".For those embedded systems that need some memory space,but don't want to increase the burden of the main control chip,PSRAM is a very pragmatic memory expansion scheme.