What is CellularRAM

What is CellularRAM® Memory?

At the highest level, our CellularRAM memory is pseudo-static DRAM with an asynchronous/page and burst interface, hidden-refresh operation, and SRAM pin-compatibility. If you dig a little deeper, what you discover is a convenient and effective combination of DRAM and SRAM characteristics designed specifically for mobile applications.

Dynamic At Heart
As you know, DRAM is a specific kind of random access memory that's structurally simple—typically with one or two transistors and capacitors per bit—and refreshes a memory cell's charge at regular intervals. DRAM, because of its elegant architecture, can be manufactured at very high densities and relatively low cost without compromising quality or performance.

Like DRAM, CellularRAM memory stores one bit of information in each of its millions of memory cells and refreshes these memory cells at regular intervals. But like SRAM, CellularRAM devices don't require external refresh support and use less power than standard DRAM.

Compatible with SRAM
Asynchronous CellularRAM devices are backward compatible with nearly all standard SRAM devices. CellularRAM generally has the same voltage range as SRAM, the same package options as SRAM, and the same ball assignments as SRAM, so you should expect a smooth transition from SRAM to feature-packed Micron CellularRAM memory. If you want specific information about moving from SRAM to CellularRAM memory, including a discussion of power supply considerations, ball assignments, controller interface, and configuration, you should read our technical note,
CellularRAM® Devices Replacing Single- and Dual-CE# SRAM.

Low-Power CellularRAM Memory Operation Modes

One of CellularRAM® memory's coolest features is how it saves power in mobile devices. Micron's CellularRAM memory includes at least four easy ways to save power in your mobile design. These methods are temperature-compensated refresh (TCR), standby mode, partial-array refresh (PAR), and deep power-down (DPD) mode. Three of these are discussed briefly below. For more detailed information, including how to configure Micron's CellularRAM memory for TCR, PAR, or DPD, you should read our technical note, Low-Power Options for Async/Page CellularRAM® Memory.

Temperature-Compensated Refresh
A DRAM cell—which is the basis of our CellularRAM devices—will respond to temperature. An increase in temperature will result in more charge degradation, while a decrease in temperature will boost charge retention. TCR and CellularRAM memory's on-chip temperature sensor allow designers to set the internal refresh oscillator frequency. TCR saves power by providing the right refresh rate at the right time and temperature.

Partial-Array Refresh
PAR is as simple as its name implies. In this operating mode, Micron's CellularRAM memory only refreshes the portion of the memory array that's being used, saving power and boosting battery life in your mobile design.

Deep Power-Down
CellularRAM memory doesn't waste power when it's not being used, plain and simple. DPD halts all refresh-related activity when the device is inactive.

CellularRAM®