SST34HF1681J

The SST34HF1681J ComboMemory devices integrate either a 1M x16 or 2M x8 CMOS flash memory bank with either a 128K x16, 256K x16, or 512K x16 CMOS SRAM or pseudo SRAM (PSRAM) memory bank in a multi-chip package (MCP). These devices are fabricated using SST's proprietary, high-performance CMOS SuperFlash technology incorporating the split-gate cell design and thick-oxide tunneling injector to attain better reliability and manufacturability compared with alternate approaches. The SST34HF16x1C/J devices are ideal for applications such as cellular phones, GPS devices, PDAs, and other portable electronic devices in a low power and small form factor system. The SST34HF16x1C/J feature dual flash memory bank architecture allowing for concurrent operations between the two flash memory banks and the (P)SRAM. The devices can read data from either bank while an Erase or Program operation is in progress in the opposite bank. The two flash memory banks are partitioned into 12 Mbit and 4 Mbit with bottom sector protection options for storing boot code, program code, configuration/parameter data and user data.

The SuperFlash technology provides fixed Erase and Program times, independent of the number of Erase/Program cycles that have occurred. Therefore, the system software or hardware does not have to be modified or de-rated as is necessary with alternative flash technologies, whose Erase and Program times increase with accumulated Erase/Program cycles. The SST34HF16x1C/J devices offer a guaranteed endurance of 10,000 cycles. Data retention is rated at greater than 100 years. With high-performance Program operations, the flash memory banks provide a typical Program time of 7 sec. The entire flash memory bank can be erased and programmed word-by-word in typically 4 seconds for the SST34HF16x1C/J, when using interface features such as Toggle Bit, Data# Polling, or RY/BY# to indicate the completion of Program operation. To protect against inadvertent flash write, the SST34HF16x1C/J devices contain on-chip hardware and software data protection schemes.

The flash and (P)SRAM operate as two independent memory banks with respective bank enable signals. The memory bank selection is done by two bank enable signals. The (P)SRAM bank enable signals, BES1# and BES2, select the (P)SRAM bank. The flash memory bank enable signal, BEF#, has to be used with Software Data Protection (SDP) command sequence when controlling the Erase and Program operations in the flash memory bank. The memory banks are superimposed in the same memory address space where they share common address lines, data lines, WE# and OE# which minimize power consumption and area.

Designed, manufactured, and tested for applications requiring low power and small form factor, the SST34HF1681J are offered in extended temperatures and a small footprint package to meet board space constraint requirements. See Figures 4 and 5 for pin assignments.