16Kbit Parallel EEPROMs with 90ns Access Times

SGS-THOMSON Microelectronics has introduced a family of four high speed 16Kbit parallel EEPROMs aimed at specialized market requirements. Derived from the popular M28C64 and M28LV64 devices, the new M28C16/17 and M28LV16/17 are 2Kx8 devices with software write protect for better data protection in noisy environments, a high erase/write endurance and fast access times down to 90ns, making the new devices ideal for use in PCMCIA cards, modems, feature phones and set-top boxes.

Built with a highly reliable single polysilicon CMOS technology, the M28C16 family offers very low field failure rates, thanks to the high erase/write endurance of at least 100,000 cycles, and fast write cycles, with a maximum programming cycle time of 3ms for a 64-byte page.

All four devices feature software handshaking via two status bits and the M28C17/LV17 devices also include hardware handshaking via a dedicated status pin (Read/Busy). Two of the data I/O pins also function as status indicators during programming cycles: DQ7 (Data Polling bit) returns the complement of the previously latched bit while a write cycle is in progress, while DQ6 (Toggle bit) toggles the returned value on successive read attempts until the write operation is finished. The Ready/Busy pin provides a signal at its open drain output that is low during the erase/write cycle and is released when the cycle is completed. These devices therefore support all current protocols.

The page-write feature means that up to 64 bytes can be consecutively latched into the memory prior to initiating a programming cycle and all 64 locations will be written within the 3ms maximum programming time. An internal page mode timer automatically initiates the programming cycle if the host does not send another address/data combination within 100us of the previous data being latched. DQ5 serves as a page mode timer status bit, a low level indicating that the timer is still running.

Other features of the new devices include JEDEC standard bytewide pinouts and a minimum data retention of 40 years. The M28C16/17 are 5V parts, while the M28LV16/17 operate over a supply voltage range of 2.7 to 3.6V. Package options are DIP24, SO24, PLCC32 and TSOP28 for the M28C16/LV16 and DIP28, SO28 and PLCC32 for the M28C17/LV17.

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