Snapback

About: Snapback is a research topic. Over the lifetime, 742 publications have been published within this topic receiving 8225 citations.

Lateral PNP BJT ESD protection devices

Abstract: A new high voltage lateral PNP with sufficient current density for small footprint ESD protection is experimentally demonstrated in a 40 V drain-extended CMOS process. It is found that a lateral PNP device can exhibit snapback behavior similar to that characteristically associated with NPN-based ESD clamps. The mechanism leading to this effect is further studied for PNPs in a BiCMOS process using physical process and device simulation. This analysis reveals that the formation of a quasi-neutral electron-hole plasma in the N-base drift region reduces the base electric field and thus the emitter-collector voltage drop, explaining the observed behavior. The advantage of this lateral PNP is to provide local ESD protection that is robust against transient latch-up.

Electrostatic discharge power clamp with improved electrical overstress robustness

Abstract: An apparatus for protecting an integrated circuit from electrostatic discharge (ESD) and electrical overstress (EOS) events includes a resistor/capacitor (RC) triggering device configured between a pair of power rails; a silicon controlled rectifier (SCR) triggered by the RC triggering device during an ESD event, wherein the SCR, when activated, acts as a power rail voltage clamp; and a field effect transistor (FET) coupled between the RC triggering device and the SCR, wherein the FET serves as an integrated part of the RC triggering device that triggers the SCR during the ESD event; and wherein the FET also operates in a snapback mode to trigger the SCR during an EOS event that is slower in comparison to the ESD event such that the EOS event would not otherwise cause triggering of the SCR via the RC triggering device itself.

Measurements of the Persistent Current Decay and Snapback Effect in Tevatron Dipole Magnets

Abstract: A systematic study of the persistent current decay and snapback effect in the fields of Tevatron accelerator dipoles was performed at the Fermilab Magnet Test Facility (MTF). The decay and snapback were measured under a range of conditions including variations of the current ramp parameters and magnet operational history. The study has mostly focused on the dynamic behavior of the normal sextupole component. In addition, the paper presents the persistent current effects observed in the other allowed field harmonics as well. The results provide new information about the previously observed "excess" decay during the first several seconds of the sextupole decay during injection and the correlation between the snapback amplitude and its duration.

A fast sextupole probe for snapback measurement in the LHC dipoles

Abstract: In superconducting particle accelerators a fast change of the magnetic field occurs during the first few seconds after the start of an energy ramp. Standard magnetic measurements using a coil rotating at 1 Hz do not have the time resolution required to completely resolve this phase, usually called snapback. For this reason we have developed a new and fast system dedicated to sextupole measurements. The basic component consists of three Hall plates mounted on a ring. In an ideal case this arrangement compensates the main dipole field and produces a signal proportional to the sextupole only. Mechanical tolerances and differences in the sensitivity of the Hall plates are compensated by instrumentation amplifiers and an in situ fine adjustment of the probe orientation. Using this hybrid compensation technique we have measured sextupole variations in an LHC dipole prototype during snapback at a rate of 5 Hz. In this paper we present details on the device and the results of our measurements.