Flash-based microcontrollers (MCUs) have been costlier than one-time programming (OTP) solutions. But Microchip Technology's patented PMOS electrically erasable cell (PEEC) technology, PICmicro Flash, significantly lowers the cost and size of MCU-based flash. Starting at $2.00, flash-based MCUs cost up to 15% less than comparable OTP versions.
The PEEC cell utilizes a Fowler Nordheim tunneling region, versus the more conventional tunnel dielectric window (see the figure). The resultant one-third cell-size reduction is due to the use of the single arch polysilicon structure. This also improves the electron flow to the floating gate underneath the arch. The process technology meshes well with Microchip's current MCU technology.
Most nonvolatile memory research has been targeted at large, standalone memory arrays for embedded processors. PEEC is employed in single-chip solutions where the flash memory is integrated with the MCU and its peripherals. Also, PEEC is incorporated into Microchip's 8-bit MCU family. Microchip's product portfolio includes a range of 8- to 84-pin MCUs.
The PICmicro Flash products are ideal for high-volume, cost-sensitive markets where OTP solutions are found. With the PICmicro Flash approach, field upgrades are now possible. And, one drawback of prior flash memory implementations was slow programming time compared to OTP. PICmicro Flash is actually faster than OTP in most in-stances. Programming a 1-Mbit array including a full erase takes less than 2 s. Individual words can be programmed in less than 3 ms.
Reliability specifications include 40-year data retention and 5 million erase/write cycles. Low-power operation down to 2 V lets PICmicro Flash-based chips operate in fluctuating or low-power environments. Microchip's MPLAB ICD supports PICmicro Flash-based chips. ICD systems start at $99. Contact Microchip about individual chip pricing. For details, go to www.microchip.com.
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