First Low-Voltage, High-Speed Quad I/O Serial Flash Memory

First Low-Voltage, High-Speed Quad I/O Serial Flash Memory provides Fastest Random Access Performance of Any Quad-bit Serial Memory

Silicon Storage Technology, Inc. (SST) has begun sampling the industry’s first 1.8V, high-speed quad-bit serial flash memory.

Featuring an 80 MHz operating frequency and a specialized instruction set, the new 26WF Series Serial Quad I/O (SQI) family of 4-bit multiplexed I/O serial interface devices enables execute-in-place (XIP) capability. XIP enables programs to be stored and executed directly from the flash memory without the need for code shadowing on an SRAM.  

The first high-performance 1.8V quad I/O serial flash device, the 26WF Series marries the performance typically associated with parallel flash memory, with the low pin count and space savings of serial flash memory. The active read current of the device is only 15 mA (typical at 80 MHz) and standby current is a mere 10 µA (typical). This combination of high performance and low power consumption makes the 26WF Series ideal for mobile handsets, Bluetooth headsets, GPS devices and other small form factor, portable electronics.

Building on the success of SST’s award winning 26VF Series of 3.0V SQI flash products, the  26WF Series features a novel read memory indexing feature that enables the device to achieve the fastest random access performance of any quad-bit serial memory. Read memory indexing allows the system to jump from one address to another within a 256-Byte page, within a 64-KByte block or from one block to another using indirect addressing. This results in a significant reduction in the number of clock cycles and dramatically accelerates data access.

With sustained burst data rates of up to 320 Mbit/sec., the 26WF Series devices provide serial flash performance exceeding that of typical parallel flash memory. To provide additional system speed and performance while reducing access time, the 26WF devices support 8-, 16-, 32- and 64-Byte burst mode operation with wrap around. This feature allows designers to execute code in burst snippets for RAM-less applications or fill cache line buffers for applications where the system architecture uses pipelining to maximize bus bandwidth.

The 26WF Series SQI devices offer memory write performance enhancements to improve overall device performance, including flexible erase capability to erase small block sectors on the chip in as little as 25 ms or the entire flash memory chip in 50 ms. The devices also support write suspend and resume operation so a program can suspend a write operation to access another block of memory within the same clock cycle.

To ensure code security, all 26WF Series devices support software write protection for individual blocks, the upper and lower 64-KBytes of memory are partitioned into smaller 8-KByte sectors that can both read- and write-lock. In addition, the devices include a one-time programmable secure ID area, consisting of a 64-bit factory programmed unique ID and a 192-bit user programmable block.  

According to Douglas Lee, vice president, Memory Products, SST, the mobile phone industry, in particular, has been yearning for a serial memory solution with high performance and extremely low power consumption: “SST is proud to be the first in the industry to achieve this highly challenging accomplishment,” Lee said. “In addition to performance and power consumption advantages, our new 26WF Series offers designers of ultra low-cost mobile handsets with a low pin count, quad I/O protocol serial flash memory that is straightforward and easy to integrate, enabling continued system cost reduction.”

All 26WF Series SQI devices are available in both commercial and industrial temperature ranges, and are offered in an 8-contact WSON (6mm x 5mm) or 8-lead SOIC (200 mil) package. In addition to the 1.8V 26WF Series, SST offers 3.0V SQI devices in 16 Mbit and 32Mbit densities.