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How does the PN junction structure (such as planar, trench) of ESD protection diodes affect their ESD discharge capability?
1. Planar PN junction:
The PN junction is located on the chip surface, junction area can be easily enlarged to withstand larger ESD pulse current (e.g., HBM 15kV), but parasitic capacitance is larger (due to large junction area), and the surface is susceptible to contamination leading to unstable breakdown voltage. Suitable for low-frequency, high-current protection scenarios (e.g., power supply VBUS)
1.1 Planar PN junction is a type formed on the surface of a semiconductor wafer through planar processes (such as photolithography, diffusion, or ion implantation)...

First, simply understand the differences between avalanche and Zener breakdown:
Avalanche breakdown: High reverse voltage enables carriers in the depletion region to gain enough energy, colliding with lattice atoms to generate new electron-hole pairs (avalanche multiplication), causing reverse current to surge sharply; Breakdown voltage increases with temperature (positive temperature coefficient), suitable for high voltage, high current scenarios (such as power supply protection)
Zener breakdown: Low reverse voltage enables the strong electric field in the depletion region to directly pull bound electrons from covalent bonds (field emission), causing reverse current to surge sharply; Breakdown voltage decreases with temperature (negative temperature coefficient)
 

1. Chip Wafer Doping Process: "Material Structure" Determines Device Characteristics Differences
 
Chip doping process is the most fundamental underlying difference between the two, directly determining key parameters such as device breakdown characteristics, chip doping process is the most fundamental underlying difference between the two, directly determining key parameters such as device breakdown characteristics, response speed, conduction capability, etc. Essentially, it adjusts doping elements (such as P-type boron, N-type phosphorus) concentration, distribution area, junction depth




Comparison Dimension
ESD Electrostatic Protection Diode
Ordinary Rectifier Diode (using...

Automotive engineers know that when locating electromagnetic interference sources in automotive electronics EMS, spectrum analyzers play a core role. They are used to capture interference frequency characteristics and locate sources combined with spatial distribution. Specific methods and parameter settings are as follows:
Step 1: Location Steps
    Preliminary frequency sweep: First use a spectrum analyzer to perform a full-band scan (usually 10kHz~6GHz, covering common automotive electronic interference bands) on the entire vehicle or target system (such as car radar, ECU), record interference signal center frequency, bandwidth, and intensity
   

1. What are the differences in electromagnetic compatibility between different brands and models of PLCs?
»»» Differences in electromagnetic compatibility between different brands and models of PLCs mainly stem from design standards, component selection, and protection levels. Specific differences and selection principles are as follows:
· Core manifestations of EMC differences:
o Immunity levels: For example, Siemens S7-1200 series electrostatic discharge immunity reaches ±8kV (contact discharge), while some domestic entry-level PLCs only ±4kV; Schneider M3...

1. What impact does high-power equipment (such as cranes, welding machines, etc.) in industrial production workshops have on the electromagnetic compatibility of PLC industrial control immunity? How to protect against it?
Answer: High-power equipment (welding machines, cranes, etc.) interfere with PLCs through both conduction and radiation paths. Specific impacts and protections are as follows:
Main impacts:

  Power interference: Voltage dips (e.g., crane startup causing 10%~30% voltage drop) or spikes (welding machine arc ignition generating kV-level spikes) during equipment start/stop, causing PLC power module overload and CPU reset
Radiation interference...

In PLC industrial control EMS, when communication cables are affected by electromagnetic interference causing data transmission errors, how to solve the problem by adding shielding and adjusting communication protocols?

1. In the complex electromagnetic environment of hospitals, what external electromagnetic interference sources (such as other medical equipment, communication devices, etc.) can easily affect medical instrument EMS?
»»» The hospital electromagnetic environment is complex. Medical instrument EMS mainly faces the following external interference sources:
· Other medical equipment:
High-frequency electrosurgical units: Generate high-frequency (0.3~5MHz) strong electromagnetic radiation during operation, which may interfere with adjacent monitors, ultrasound devices
MRI/CT equipment: MRI's strong magnetic field (1.5T/3.0T) and RF pulses (64~3...

Spark plug ignition generates tens of thousands of volts of high voltage to break down air, forming a strong electromagnetic pulse (EMP)
Entertainment system (radio, Bluetooth modules, operating at 88-108MHz, 2.4GHz), navigation system (GPS 1.5GHz), air conditioning compressor (motor commutation interference, 100kHz-10MHz), car charger (switching power supply noise, 50kHz-1GHz)