Fujitsu Microelectronics introduced a stacked Multi-Chip package (MCP) integrating 64Mbit dual-operation Flash memory and 32Mbit Mobile FCRAM™, designed to provide the low power and high density required for the latest cellular telephones. Fujitsu's new MB84VD23483EJ combines the NOR-type Flash memory and the mobile FCRAM with an SRAM-compatible asynchronous interface.

The functionality provided by the latest generation of mobile phones and other wireless communication devices, including full motion video, still camera imaging, digital radio reception, personal organizer facilities and other advanced features has been rapidly expanding, making services such as Internet access, E-mail, video gaming, music downloading and video streaming everyday activities.

Combining high density, high speed and low power, this MCP packaged device makes an excellent choice for these latest mobile phones. Capable of operating from a 2.7V to 3.1V power supply, the Flash memory in standby mode offers a maximum power consumption of only five microamps, while the mobile FCRAM consumes just 10 microamps in power-down mode and 100 microamps during operating conditions. Flash read and program access times are typically 16ns and access time for FCRAM is typically 90ns.

The new stacked MCP incorporates Fujitsu's FlexBank™ architecture embedded in the Flash memory, which allows flexible allocation of data or programs to banks according to customers' system requirements. Dual operation Flash architecture enables the device to read from one partition while programming or erasing in another, making it possible to achieve high-speed processing.

Fujitsu Microelectronics, Inc., 3545 North First Street, San Jose, CA 95134-1804. Phone: 408-922-9104.

Fujitsu Microelectronics Europe, Am Siebenstein 6-10 D-63303 Dreieich-Buchschlag, Germany. Phone: +49-6103-690257; Fax: +49-6103-690122

FCRAM is Fujitsu's fast cycle RAM. It includes memory-array segmentation and internal pipelining that speeds random access and reduces power consumption, something that is really helpful to today's designers.

As a design engineer you already know it but the use of DRAM in market sectors such as computer products (PCs, workstations and servers), consumer products (digital TVs, digital still cameras, video disks and set-top boxes) and telecommunications and networking-related products (switches, routers, mobile/cellular phones, PDAs and network servers) has increased dramatically. However, many of the applications need higher performance and more diversified memory products, which is causing the DRAM market to segment by application and performance. Since conventional commodity DRAMs cannot satisfy all the different requirements of these applications, there is a need for application specific memory (ASM) products, particularly for rapidly evolving multimedia, networking and graphics systems. This trend is similar to the market shift that impacted logic devices.

The new ASMs use an asynchronous SRAM-type interface and refresh-free operation with low power for long battery life. This also makes it easy to upgrade memory without the need for significant changes in system architecture.

The multichip packaging design stacks the flash memory and SRAM on top of each other, rather than side by side. This vertical stacking is said to achieve a space saving over conventional planar MCPs, virtually doubling the amount of memory that can be packed into a specified area.

Vertical stacking can pack a 16M flash/ 2M SRAM MCP into 81sq mm, a space reduction of more than 40% over the planar equivalent. The design uses an SRAM die with a pin assignment compatible with that of the flash memory, which allows stacking with minimal wiring. The design also means the stacked format will be compatible with future generations of high density flash memory.

Samples of the MB84VD23483EJ MCP in standard plastic 81 ball BGA packages are now available and mass production will start in October.

Data sheet: http://www.fmi.fujitsu.com/pdf/mb84vd23483ej.pdf