A simple Flash memory cell model for transient circuit simulation
A simple Flash memory cell model for circuit simulation is presented. The proposed model gives an excellent fitting of dc and transient data and does not require additional simulation time comparing with that of a MOSFET transistor. Effective control-gate voltage method and ideal current-mirror technique are introduced to calculate floating-gate voltage. These allow macro modeling of a Flash memory cell in a circuit simulator.
A Spice-compatible flash EEPROM model feasible for transient and program/erase cycling endurance simulation
A complete Spice-compatible model for stacked-gate flash EEPROM cells has been successfully developed. It includes an accurate DC I-V model, a gate current model for Channel Hot Electron (CHE) programming; and a channel Fowler-Nordheim (FN) current model for erase. Program and erase induced oxide damage are also included in the model. For the first time, it allows the simulation of the programming/erase transient and the P/E cycling endurance characteristics using the present analytical approach. It provides an easy way for applications to cell design optimization and reliability evaluation for device and circuit designers.
The fragmentation of small asteroids in the atmosphere
The fragmentation of a small asteroid in the atmosphere greatly increases its cross-sections for aerodynamic braking and energy dissipation. The differential pressure across a meteoroid disperses its fragments at a velocity that increases with atmospheric density and impact velocity and decreases with meteoroid density. At a typical impact velocity of 22 km/s, the atmosphere absorbs more than half the kinetic energy of stony meteoroids with diameters, D M < 220 M AND IRON METEOROIDS WITH D M < 80 m. The corresponding diameter for comets with impact velocity 50 km/s is D M < 1600 m. Most of this energy dissipation occurs in a fraction of a scale height, which causes large meteoroids to appear to »explode« or »flare« at the end of their visible paths