Here be dragons: Preventing static damage, latchup, and metastability in the 386
7 days ago
- #Intel 386
- #Hardware Engineering
- #Circuit Design
- The Intel 386 processor's I/O pins face dangers like static electricity, latchup, and metastability, requiring specialized protection circuits.
- Static electricity can destroy the chip by damaging the thin oxide layer in MOS transistors; protection includes diodes and resistors to redirect excess voltage.
- Latchup occurs when parasitic transistors in the silicon substrate form a feedback loop, potentially destroying the chip; guard rings are used to prevent this.
- Metastability is a problem where digital signals take an unpredictable time to settle, risking malfunctions; the 386 uses synchronizers with two flip-flops to mitigate this.
- The 386's I/O circuits vary by pin function, with different designs for data, address, and control pins, emphasizing analog considerations in digital design.