©2003 Silicon Storage Technology, Inc.

S71107-05-000

12/03

1

The SST logo and SuperFlash are registered trademarks of Silicon Storage Technology, Inc.

ComboMemory is a trademark of Silicon Storage Technology, Inc.

These specifications are subject to change without notice.

Preliminary Specifications

FEATURES:

•

Monolithic Flash + SRAM ComboMemory

– SST31LF041/041A: 512K x8 Flash + 128K x8 SRAM

•

Single 3.0-3.6V Read and Write Operations

•

Concurrent Operation

– Read from or Write to SRAM while

Erase/Program Flash

•

Superior Reliability

– Endurance: 100,000 Cycles (typical)

– Greater than 100 years Data Retention

•

Low Power Consumption:

– Active Current: 10 mA (typical) for Flash and

20 mA (typical) for SRAM Read

– Standby Current: 10 µA (typical)

•

Flash Sector-Erase Capability

– Uniform 4 KByte sectors

•

Latched Address and Data for Flash

•

Fast Read Access Times:

– SST31LF041/041A

Flash: 70 ns

SRAM: 70 ns

– SST31LF041A

Flash: 300 ns

SRAM: 300 ns

•

Flash Fast Erase and Byte-Program:

– Sector-Erase Time: 18 ms (typical)

– Bank-Erase Time: 70 ms (typical)

– Byte-Program Time: 14 µs (typical)

– Bank Rewrite Time: 8 seconds (typical)

•

Flash Automatic Erase and Program Timing

•

Flash End-of-Write Detection

– Toggle Bit

– Data# Polling

•

CMOS I/O Compatibility

•

JEDEC Standard Command Set

•

Packages Available

– 32-lead TSOP (8mm x 14mm) SST31LF041A

– 40-lead TSOP (10mm x 14mm) SST31LF041

PRODUCT DESCRIPTION

The SST31LF041/041A devices are a 512K x8 CMOS

flash memory bank combined with a 128K x8 CMOS

SRAM memory bank manufactured with SST’s proprietary,

high

performance

SuperFlash

technology.

The

SST31LF041/041A devices write (SRAM or flash) with a

3.0-3.6V power supply. The monolithic SST31LF041/041A

devices conform to Software Data Protect (SDP) com-

mands for x8 EEPROMs.

Featuring high performance Byte-Program, the flash mem-

ory bank provides a maximum Byte-Program time of 20

µsec. The entire flash memory bank can be erased and

programmed byte-by-byte in typically 8 seconds, when

using interface features such as Toggle Bit or Data# Polling

to indicate the completion of Program operation. To protect

against inadvertent flash write, the SST31LF041/041A

devices have on-chip hardware and Software Data Protec-

tion schemes. Designed, manufactured, and tested for a

wide spectrum of applications, the SST31LF041/041A

devices are offered with a guaranteed endurance of 10,000

cycles. Data retention is rated at greater than 100 years.

The SST31LF041/041A operate as two independent mem-

ory banks with respective bank enable signals. The SRAM

and flash memory banks are superimposed in the same

memory address space. Both memory banks share com-

mon address lines, data lines, WE# and OE#. The memory

bank selection is done by memory bank enable signals.

The SRAM bank enable signal, BES# selects the SRAM

bank and the flash memory bank enable signal, BEF#

selects the flash memory bank. The WE# signal has to be

used with Software Data Protection (SDP) command

sequence when controlling the Erase and Program opera-

tions in the flash memory bank. The SDP command

sequence protects the data stored in the flash memory

bank from accidental alteration.

The SST31LF041/041A provide the added functionality of

being able to simultaneously read from or write to the

SRAM bank while erasing or programming in the flash

memory bank. The SRAM memory bank can be read or

written while the flash memory bank performs Sector-

Erase, Bank-Erase, or Byte-Program concurrently. All flash

memory Erase and Program operations will automatically

latch the input address and data signals and complete the

operation in background without further input stimulus

requirement. Once the internally controlled Erase or Pro-

gram cycle in the flash bank has commenced, the SRAM

bank can be accessed for Read or Write.

The SST31LF041/041A devices are suited for applications

that use both nonvolatile flash memory and volatile SRAM

memory to store code or data. For all system applications,

the SST31LF041/041A devices significantly improve per-

formance and reliability, while lowering power consumption,

when compared with multiple chip solutions. The

4 Mbit Flash + 1 Mbit SRAM ComboMemory

SST31LF041 / SST31LF041A

SST31LF041 / 041A4Mb Flash (x8) + 1Mb SRAM (x8) Monolithic ComboMemory