概觀
The IS25WQ040/020 (4M/2Mbit) Serial Flash memory offers a storage solution with flexibility and performance in a
simplified pin count package. ISSI’s “Industry Standard Serial Interface” is for systems that have limited space, pins,
and power. The IS25WQ040/020 is accessed through a 4-wire SPI Interface consisting of a Serial Data Input (SI), Serial
Data Output (SO), Serial Clock (SCK), and Chip Enable (CE#) pins, which also serve as multi-function I/O pins in Dual
and Quad modes (see pin descriptions). The IS25xQ series of Flash is ideal for code shadowing to RAM, execute in
place (XIP) operations, and storing non-volatile data.
The memory array is organized into programmable pages of 256-bytes each. The IS25WQ040/020 supports page
program mode where 1 to 256 bytes of data can be programmed into the memory with one command. Pages can be
erased in groups of 4K-byte sectors, 32K-byte blocks, 64K-byte blocks, and/or the entire chip. The uniform sectors and
blocks allow greater flexibility for a variety of applications requiring solid data retention.
The device supports the standard Serial Peripheral Interface (SPI), Dual/Quad output (SPI), and Dual/Quad I/O (SPI).
Clock frequencies of up to 104MHz for all read modes allow for equivalent clock rates of up to 416MHz (104MHz x 4)
allowing up to 52MBytes/S of throughput. These transfer rates can outperform 16-bit Parallel Flash memories allowing
for efficient memory access for a XIP (execute in place) operation. The IS25WQ040/020 is manufactured using industry
leading non-volatile memory technology and offered in industry standard lead-free packages. See Ordering Information
for the density and package combinations available.