Table of Contents
What is Latchup issue?
Latch-Up is a condition where a low impedance path is created between a supply pin and ground. This condition is caused by a trigger (current injection or overvoltage), but once activated, the low impedance path remains even after the trigger is no longer present.
What causes Latchup?
A common cause of latch-up is a positive or negative voltage spike on an input or output pin of a digital chip that exceeds the rail voltage by more than a diode drop. Another cause is the supply voltage exceeding the absolute maximum rating, often from a transient spike in the power supply.
What is Latchup in IGBT?
Latch-up results from turning on of the parasitic PNPN thyristor. At that point, the IGBT current is no longer controlled by the. MOS gate. The IGBT would be destroyed unless the current is externally forced OFF.
What is latch-up in layout?
Early CMOS processes suffered a reliability concern that became known as latchup. It resulted in circuits either malfunctioning or consuming excessive power, and could be either inherent in the design or triggered by voltage spikes on IO pads that could forward bias PN junctions they were connected to.
What is threshold voltage in VLSI?
The threshold voltage, commonly abbreviated as Vth, of a field-effect transistor (FET) is the minimum gate-to-source voltage VGS (th) that is needed to create a conducting path between the source and drain terminals. It is an important scaling factor to maintain power efficiency.
What is a triac How does a triac differ from a DIAC?
TRIAC stands for Triode AC switch. DIAC is a bidirectional device that lets current pass through it in both directions when the voltage across the terminals reaches break-over voltage. TRIAC is also a bidirectional device that lets the current pass through it when its gate terminal is triggered.
How is the IGBT turned off?
One of the main advantages of the IGBT transistor is the simplicity by which it can be driven “ON” by applying a positive gate voltage, or switched “OFF” by making the gate signal zero or slightly negative allowing it to be used in a variety of switching applications.
How tap cells avoid latch-up?
Well tap cells (or Tap cells) are used to prevent the latch-up issue in the CMOS design. Well tap cells connect the nwell to VDD and p-substrate to VSS in order to prevent the latch-up issue.
What is latch up problem in VLSI design?
Latch Up Problem in CMOS – VLSI Design. Latch-up is defined as the generation of a low-impedance path in CMOS chips between the power supply (VDD) and the ground (GND) due to the interaction of parasitic PNP and NPN bipolar junction transistors (BJTs).
What is latchup in ICS?
What is Latchup: Latchup refers to short circuit formed between power and ground rails in an IC leading to high current and damage to the IC. Speaking about CMOS transistors, latch up is the phenomenon of low impedance path between power rail and ground rail due to interaction between parasitic pnp and npn transistors.
What is latchup and its prevention in CMOS?
Latchup and its prevention in CMOS devices. What is Latchup: Latchup refers to short circuit formed between power and ground rails in an IC leading to high current and damage to the IC. Speaking about CMOS transistors, latch up is the phenomenon of low impedance path between power rail and ground rail due to interaction between parasitic pnp
What is a latch-up short circuit?
A latch-up is a type of short circuit which can occur in an integrated circuit (IC). More specifically it is the inadvertent creation of a low-impedance path between the power supply rails of a MOSFET circuit, triggering a parasitic structure which disrupts proper functioning of the part, possibly even leading to its destruction due to overcurrent.