Protection Diodes in Electronic Circuits
1. Definition and Purpose of Protection Diodes
Definition and Purpose of Protection Diodes
Protection diodes are semiconductor devices strategically placed in electronic circuits to safeguard sensitive components from voltage transients, reverse polarity, and electrostatic discharge (ESD). Their primary function is to clamp or divert harmful electrical surges away from critical circuitry, ensuring operational integrity and longevity.
Fundamental Operating Principles
Protection diodes exploit the nonlinear current-voltage (I-V) characteristics of PN junctions. Under normal operating conditions, they remain reverse-biased, presenting high impedance. When transient voltages exceed a threshold, the diode enters either forward conduction (for reverse polarity protection) or avalanche breakdown (for overvoltage clamping).
where Vbr is the breakdown voltage, Id the surge current, and Rdynamic the diode's dynamic resistance during conduction.
Key Protection Mechanisms
- Reverse Polarity Protection: Series diodes block current flow when power supply polarity is reversed, while parallel diodes short-circuit reverse voltages.
- Voltage Clamping: Zener diodes or TVS (Transient Voltage Suppression) diodes shunt excess voltage to ground when exceeding their breakdown potential.
- Inductive Load Spike Suppression: Flyback diodes provide a current path for decaying inductive currents, preventing damaging voltage spikes.
Performance Parameters
Critical specifications include:
Parameter | Description | Typical Range |
---|---|---|
Breakdown Voltage (Vbr) | Voltage at which diode begins conducting in reverse | 5V - 400V |
Peak Pulse Current (Ipp) | Maximum surge current handling capability | 10A - 1000A |
Response Time | Delay before effective clamping | 1ps - 1ns |
Practical Implementation Considerations
Effective protection requires:
- Placement proximity to protected components (minimizing parasitic inductance)
- Proper heat dissipation calculations for high-energy transients
- Coordination with other protection elements (fuses, varistors)
where Emax must not exceed the diode's energy rating.
Key Characteristics of Protection Diodes
Breakdown Voltage (VBR)
Protection diodes are designed to clamp transient voltages by entering avalanche or Zener breakdown when the reverse voltage exceeds a specified threshold, known as the breakdown voltage (VBR). For Zener diodes, this is a precisely controlled parameter, typically ranging from 2.4 V to 200 V. Avalanche diodes, used for higher voltage applications, exhibit a positive temperature coefficient, whereas Zener diodes below 5.6 V have a negative temperature coefficient. The breakdown mechanism is derived from the electric field strength:
where Ec is the critical electric field (≈3×105 V/cm for silicon) and W is the depletion width. The temperature dependence of VBR follows:
Peak Pulse Power (PPP)
Transient voltage suppressors (TVS diodes) are rated by their peak pulse power dissipation, defined as:
where Vclamp is the maximum clamping voltage, IPP is the peak pulse current, and tp is the pulse duration (typically 8/20 μs or 10/1000 μs waveforms). For example, a 600W TVS diode might clamp a 100A surge at 6V for 20 μs. The energy absorption capability scales with the diode's junction area.
Response Time
Protection diodes must respond faster than the protected circuit's vulnerability window. PN junction diodes achieve sub-nanosecond response (≈1 ps for avalanche multiplication to initiate), but package inductance dominates the actual performance. The total response time (tr) is the sum of:
- Carrier transit time across the depletion region
- RC time constant of the junction capacitance (Cj) and system impedance
- Propagation delay in the diode's package (≈1 ns/inch for leaded devices)
Junction Capacitance (Cj)
The voltage-dependent junction capacitance impacts high-frequency signal integrity. For abrupt junctions:
where Cj0 is the zero-bias capacitance and Vbi is the built-in potential (≈0.7V for silicon). Low-capacitance TVS diodes (e.g., <0.5 pF) are essential for protecting RF lines above 1 GHz.
Leakage Current (IR)
In the blocking state, protection diodes exhibit reverse leakage current due to minority carrier diffusion and generation-recombination:
where A is the junction area, D and L are diffusion coefficients/lengths, and τeff is the effective carrier lifetime. High-temperature operation exacerbates leakage, with typical values ranging from 1 μA (small signal diodes) to 100 μA (high-power TVS).
Clamping Voltage Ratio
The effectiveness of a protection diode is quantified by its clamping ratio (K):
High-performance TVS diodes achieve K ≈ 1.2–1.5, whereas standard Zeners may exhibit K > 2. The dynamic resistance (Rd = dV/dI) during conduction determines how sharply the diode clamps; values below 0.1 Ω are typical for robust protection devices.
Failure Modes
Under extreme overstress, protection diodes fail via:
- Thermal runaway: Localized heating reduces VBR, creating positive feedback
- Metal migration: High current density induces electromigration in bond wires
- Secondary breakdown: Current filamentation causes destructive hot spots
Qualification tests per MIL-STD-750 or AEC-Q101 verify robustness against these mechanisms.
Common Types of Protection Diodes
Transient Voltage Suppression (TVS) Diodes
TVS diodes are designed to clamp transient overvoltages, such as electrostatic discharge (ESD) and lightning-induced surges, by rapidly avalanching at a predefined breakdown voltage. The key parameter is the peak pulse power rating, given by:
where VBR is the breakdown voltage and IPP is the peak pulse current. TVS diodes exhibit a nonlinear I-V characteristic, with response times typically under 1 ns. Bidirectional TVS diodes are commonly used in AC circuits, while unidirectional variants protect DC systems.
Zener Diodes
Zener diodes exploit the reverse breakdown effect to regulate voltage. Unlike TVS diodes, they are optimized for steady-state operation rather than transient suppression. The Zener voltage VZ follows the empirical relationship:
where V0 is the nominal breakdown voltage, rZ is the dynamic impedance, and IZ is the operating current. Zener diodes with breakdown voltages below 5.6 V exhibit negative temperature coefficients, while higher-voltage variants have positive coefficients.
Schottky Barrier Diodes
Schottky diodes, formed by a metal-semiconductor junction, provide fast switching and low forward voltage drop (typically 0.15-0.45 V). Their reverse recovery time is negligible compared to p-n junction diodes, making them ideal for high-frequency protection. The forward current is governed by thermionic emission:
where A is the area, A* is Richardson's constant, and φB is the barrier height.
Varistors (MOVs)
Metal-oxide varistors (MOVs) are polycrystalline ceramic devices with highly nonlinear voltage-current characteristics. Their resistance drops sharply above a threshold voltage, described by the empirical relation:
where α typically ranges from 20 to 50. MOVs are commonly used in AC power line protection but degrade with each surge event due to grain boundary breakdown.
Gas Discharge Tubes (GDTs)
GDTs provide high-current handling capability (up to 100 kA) by ionizing inert gas between electrodes when the ionization potential is exceeded. The triggering voltage follows Paschen's law:
where p is gas pressure, d is electrode spacing, and γse is the secondary emission coefficient. GDTs have slow response times (~μs) but can handle much larger energies than semiconductor devices.
Comparison of Key Parameters
Type | Response Time | Max Current | Clamping Voltage | Capacitance |
---|---|---|---|---|
TVS Diode | < 1 ns | 100 A | 5-500 V | 0.5-50 pF |
Zener | ns-μs | 1-10 A | 2-200 V | 10-100 pF |
Schottky | ps-ns | 1-100 A | 15-100 V | 10-1000 pF |
MOV | ns-μs | 10 kA | 50-1000 V | 10-100 nF |
GDT | μs-ms | 100 kA | 50-500 V | < 1 pF |
2. Reverse Voltage Protection
2.1 Reverse Voltage Protection
Reverse voltage occurs when the polarity of a power supply is inadvertently reversed, leading to potential damage in sensitive electronic components. A protection diode, typically a Schottky or fast-recovery diode, is placed in series or parallel to block or shunt reverse current, respectively.
Series Diode Configuration
In a series configuration, the diode is placed in the forward path of the power supply. Under normal operation, the diode conducts, allowing current to flow. When reverse voltage is applied, the diode becomes reverse-biased, blocking current flow. The voltage drop across the diode (VF) must be accounted for in power-sensitive designs.
Schottky diodes are preferred due to their low forward voltage drop (0.2–0.5 V) and fast switching characteristics.
Parallel Diode Configuration
In parallel (crowbar) configurations, the diode is placed across the load with reverse polarity. Under normal operation, the diode remains reverse-biased. If reverse voltage is applied, the diode conducts, shorting the supply and protecting downstream components. A fuse or current-limiting resistor is often required to prevent excessive current.
Transient Voltage Suppression (TVS) Diodes
For high-energy transients, bidirectional TVS diodes clamp reverse voltages to a safe level. Their breakdown voltage (VBR) must exceed the operating voltage but remain below the component’s maximum rating.
Practical Considerations
- Leakage Current: Reverse-biased diodes exhibit leakage (IR), which can affect low-power circuits.
- Power Dissipation: In parallel configurations, power dissipation (P = Vreverse × Ifault) must be within the diode’s ratings.
- Response Time: Fast-recovery diodes (e.g., < 50 ns) are critical for high-speed circuits.
In motor control or inductive load applications, a flyback diode is often paired with reverse voltage protection to manage back-EMF.
2.2 Overvoltage Protection (Transient Voltage Suppression)
Mechanism of Transient Voltage Suppression (TVS) Diodes
Transient Voltage Suppression (TVS) diodes are semiconductor devices designed to clamp voltage spikes by shunting excess current when the induced voltage exceeds the breakdown threshold. Unlike conventional Zener diodes, TVS diodes respond to transients in picoseconds, making them ideal for suppressing electrostatic discharge (ESD), inductive load switching, and lightning-induced surges. The critical parameters include:
- Breakdown Voltage (VBR): The minimum reverse voltage at which the diode begins conducting.
- Clamping Voltage (VC): The maximum voltage during surge conditions.
- Peak Pulse Current (IPP): The maximum surge current the diode can handle without damage.
Mathematical Derivation of Clamping Behavior
The clamping voltage \( V_C \) under transient conditions is derived from the diode's dynamic resistance \( R_D \) and the surge current \( I_{PP} \):
For a TVS diode with \( V_{BR} = 12V \), \( R_D = 1\Omega \), and \( I_{PP} = 50A \), the clamping voltage becomes:
Energy Dissipation and Power Rating
TVS diodes must dissipate the energy of the transient, calculated as:
For a rectangular pulse of duration \( t_p \), this simplifies to:
Exceeding the diode's energy rating \( E_{max} \) leads to catastrophic failure. For example, a 600W TVS diode rated for 10/1000µs pulses can handle:
Practical Applications
TVS diodes are deployed in:
- Industrial Automation: Protecting PLCs from inductive kickback.
- Telecommunications: Shielding DSL lines from lightning strikes.
- Automotive: Safeguarding CAN bus interfaces against load-dump transients.
Case Study: ESD Protection in USB 3.0 Interfaces
A bidirectional TVS diode (e.g., SMF3.3) is used to protect USB data lines. With \( V_{BR} = 3.3V \) and \( C_D = 0.5pF \), it ensures signal integrity while clamping ESD spikes below \( 9V \) per IEC 61000-4-2 Level 4 (±8kV contact discharge).
2.3 Inductive Load Protection (Flyback Diodes)
When an inductive load, such as a relay coil, solenoid, or motor winding, is de-energized, the sudden collapse of current through the inductor generates a large voltage spike due to Faraday's law of induction. This transient voltage, often referred to as back electromotive force (back-EMF), can reach hundreds of volts, posing a significant risk to semiconductor components like transistors or MOSFETs driving the load.
Physics of Inductive Kickback
The voltage spike generated by an inductor when current is interrupted is governed by:
where VL is the induced voltage, L is the inductance, and di/dt is the rate of current change. For fast switching (high di/dt), VL can far exceed the supply voltage, leading to avalanche breakdown in solid-state devices.
Flyback Diode Operation
A flyback diode (also called a freewheeling diode or snubber diode) is connected in reverse bias across the inductive load. When the driving transistor turns off, the diode provides a low-impedance path for the decaying inductor current, clamping the voltage to:
where VF is the diode's forward voltage (typically 0.7V for silicon). This prevents destructive voltage spikes while allowing the inductor's stored energy to dissipate safely through resistive losses.
Diode Selection Criteria
Key parameters for flyback diode selection include:
- Peak Inverse Voltage (PIV): Must exceed the supply voltage.
- Forward Current Rating: Should handle the load's steady-state current.
- Reverse Recovery Time (trr): Fast-recovery or Schottky diodes are preferred for high-speed switching.
Practical Implementation
For optimal performance:
- Place the diode as close as possible to the inductive load to minimize parasitic inductance in the loop.
- In high-frequency applications, use Schottky diodes (low trr) to prevent ringing.
- For bidirectional protection in H-bridge motor drivers, employ a diode bridge or TVS diodes.
Advanced Considerations
In systems requiring faster energy dissipation (e.g., PWM motor control), a zener diode or resistor-capacitor (RC) snubber can be added in series with the flyback diode to reduce the decay time constant:
where Rsnubber is the added damping resistance.
3. Criteria for Choosing Protection Diodes
3.1 Criteria for Choosing Protection Diodes
Voltage Ratings and Breakdown Characteristics
The reverse standoff voltage (VRWM) of a protection diode must exceed the maximum operating voltage of the circuit. For transient suppression, the breakdown voltage (VBR) should be slightly higher than VRWM to avoid leakage during normal operation. The clamping voltage (VC) during a transient event is derived from the diode's dynamic resistance (Rd) and peak current (IPP):
For example, a 12V circuit exposed to 100A transients might require a diode with VBR = 15V and Rd = 0.1Ω, yielding VC = 25V.
Current Handling and Energy Dissipation
Peak pulse current (IPP) and energy absorption (W) are critical for surge protection. The energy dissipated during a transient is:
For rectangular pulses, this simplifies to W ≈ VC × IPP × tp, where tp is pulse duration. Diodes like TVS devices are rated for IPP values up to 100A (8/20μs waveform) and energy in joules.
Response Time and Capacitance
Protection diodes must react faster than the transient rise time. Avalanche diodes respond in picoseconds, while Schottky diodes trade speed for higher capacitance (CJ), which can distort high-frequency signals. The cutoff frequency (fC) is:
where RS is the system impedance. For USB 3.0 (5Gbps), diodes with CJ < 0.5pF are essential.
Thermal Management
Junction temperature (TJ) must remain below the maximum rated value during transients. The thermal impedance (Zth) and power dissipation determine TJ:
For a 10ms pulse, Zth might be 10°C/W. A 100A, 25V event would raise TJ by 25°C above ambient (TA).
Package and Layout Considerations
Surface-mount (SMD) diodes minimize parasitic inductance, critical for high-di/dt transients. Leaded packages introduce inductance (Lpar), causing voltage overshoot:
A 10nH lead in a 100A/μs transient adds 1V overshoot. Use Kelvin connections for low-inductance layouts.
---Real-World Example: ESD Protection for HDMI
HDMI 2.1 requires diodes with:
- VRWM ≥ 5V, VBR ≤ 6V
- CJ < 0.3pF to preserve signal integrity
- IPP > 5A (8kV ESD, IEC 61000-4-2)
Devices like the TPD2E007 meet these criteria with a 0.2pF capacitance and 8A IPP.
3.2 Placement and Circuit Integration
Optimal Diode Placement for Transient Suppression
Protection diodes must be placed as close as possible to the sensitive component they are guarding to minimize parasitic inductance in the path. The voltage spike Vspike induced by an inductive load is given by:
where L is the parasitic inductance and di/dt is the rate of current change. A poorly placed diode introduces additional loop inductance, reducing its effectiveness. For instance, a 10 cm wire trace with 10 nH/cm inductance adds 100 nH, exacerbating transient voltages.
Bidirectional vs. Unidirectional Protection
In circuits with alternating polarity signals, such as motor drivers or H-bridges, bidirectional transient voltage suppression (TVS) diodes are essential. Their placement must account for both positive and negative transients. The clamping voltage Vclamp is derived from the diode's breakdown characteristics:
where Vbr is the breakdown voltage, Rd is the dynamic resistance, and Ipp is the peak pulse current. For unidirectional diodes, reverse placement can lead to failure during negative transients.
Integration with Power Rails and Ground
When integrating protection diodes into power rails, the following considerations apply:
- Power rail clamping: Place TVS diodes between VCC and ground, ensuring minimal loop area to reduce EMI.
- Ground bounce mitigation: Use Schottky diodes for low forward voltage (Vf ≈ 0.3 V) to divert transients before they corrupt ground references.
- High-frequency bypassing: Pair diodes with ceramic capacitors (e.g., 100 nF) to absorb high-frequency energy and prevent ringing.
Case Study: Diode Placement in Motor Drive Circuits
In a brushed DC motor circuit, freewheeling diodes must be placed directly across the motor terminals. The stored inductive energy EL is:
Without proper diode placement, this energy dissipates as arcing across the switch contacts, leading to premature failure. A correctly placed diode ensures energy recirculation, protecting both the motor and driving transistor.
Thermal Considerations and PCB Layout
Under high transient conditions, diodes dissipate significant power:
where tpulse is the pulse width and frep is the repetition frequency. To prevent thermal runaway:
- Use wide copper traces for low thermal resistance.
- Place diodes away from heat-sensitive components.
- Consider heatsinking for high-power applications (>5 W).
Advanced Techniques: Cascaded Protection
For ultra-sensitive circuits, a multi-stage approach combines:
- Primary stage: Gas discharge tubes or MOVs for high-energy absorption.
- Secondary stage: TVS diodes for faster response to residual transients.
- Tertiary stage: RC snubbers to damp high-frequency oscillations.
The impedance mismatch between stages must be carefully managed to prevent reflections. The characteristic impedance Z0 of the PCB trace influences this:
where L and C are the distributed inductance and capacitance per unit length.
3.3 Practical Design Considerations
Diode Selection Criteria
When selecting protection diodes, key parameters include reverse standoff voltage (VR), peak pulse current (IPP), and response time. For transient voltage suppression (TVS) diodes, the clamping voltage (VC) must be below the protected circuit's maximum rated voltage. The power dissipation during a transient event is given by:
where tpulse is the pulse duration and Ï„ is the thermal time constant of the diode.
Placement and Routing
Protection diodes must be placed as close as possible to the protected node, with minimal trace inductance. For high-speed interfaces (e.g., USB, HDMI), the total loop inductance (Lloop) should satisfy:
where Vsurge is the expected surge voltage and di/dt is the current slew rate. A four-layer PCB with ground planes reduces inductance compared to two-layer designs.
Thermal Management
During sustained overvoltage events, the junction temperature (Tj) must not exceed the diode's rated limit. For a TVS diode absorbing energy E, the temperature rise is:
where Rth(j-a) is the junction-to-ambient thermal resistance and Aeff is the effective area for heat dissipation. Heatsinking or copper pours may be necessary for multi-kilojoule surges.
Fail-Safe Mechanisms
In mission-critical systems, redundant diode networks with current-limiting resistors (Rlimit) prevent single-point failures. The resistor value is chosen to limit fault current to the diode's IPP:
Polymeric positive temperature coefficient (PPTC) devices can complement diodes by providing resettable overcurrent protection.
EMI and Signal Integrity
Protection diodes introduce parasitic capacitance (Cj), which can distort high-frequency signals. For a 50Ω transmission line, the −3dB bandwidth limitation is:
Low-capacitance TVS diodes (Cj < 0.5pF) are essential for GHz-range interfaces. Differential pairs require matched diode networks to maintain impedance symmetry.
Case Study: Automotive Load Dump Protection
ISO 7637-2 specifies a 100ms, 40V load dump pulse for 12V automotive systems. A TVS diode with VR = 18V and IPP = 100A, paired with a 1Ω series resistor, limits the clamped energy to 40J. The diode's thermal mass must absorb this energy without exceeding Tj(max) = 150°C.
4. Essential Books and Papers
4.1 Essential Books and Papers
- Electronic Devices and Circuit Theory.pdf - Google Drive — 1 SEMICONDUCTOR DIODES 1 1.1 Introduction 1 1.2 Ideal Diode 1 1.3 Semiconductor Materials 3 1.4 Energy Levels 6 1.5 Extrinsic Materials—n- and p-Type 7 1.6 Semiconductor Diode 10 1.7 Resistance Levels 17 1.8 Diode Equivalent Circuits 24 1.9 Diode Specification Sheets 27 1.10 Transition and Diffusion Capacitance 31 1.11 Reverse Recovery Time 32
- (PDF) CHAPTER 4 Diodes - Academia.edu — CHAPTER 4 Diodes Introduction 175 4.5 Rectifier Circuits 207 4.1 The Ideal Diode 176 4.6 Limiting and Clamping Circuits 221 4.2 Terminal Characteristics of Junction Diodes 184 4.7 Special Diode Types 227 4.3 Modeling the Diode Forward Characteristic 190 4.4 Operation in the Reverse Breakdown Region—Zener Diodes 202 Summary 229 Problems 230 IN ...
- PDF Understanding Modern Transistors and Diodes — 8 Light-emitting diodes 138 8.1 Voltage efï¬ciency 138 8.2 Current efï¬ciency 140 8.2.1 Heterojunction diodes 141 8.3 Radiative recombination efï¬ciency 142 8.4 Extraction efï¬ciency 143 8.5 Wall-plug efï¬ciency 146 8.6 Luminous efï¬cacy and efï¬ciency 146 8.7 White-light LEDs 147 8.8 Prospects for general-purpose solid-state lighting ...
- PDF Fundamentals of Electronic Circuit Design - University of Cambridge — 3.8.3 Redrawing Circuits in Different Frequency Ranges 4 Source and Load 4.1 Practical Voltage and Current Sources 4.2 Thevenin and Norton Equivalent Circuits 4.3 Source and Load Model of Electronic Circuits 5 Critical Terminology 5.1 Buffer 5.2 Bias 5.3 Couple 6 Diodes 6.1 Diode Basics 6.2 Diode circuits
- Chapter 4. Diodes - Applied Electrical Engineering Fundamentals - UMass — The terms "electronic engineering" and "electronics" refer to the design and use of circuits containing semiconductors, such as diodes, transistors, and integrated circuits (IC's). "Electrical engineering", in contrast, refers to power lines and other circuit applications that historically have not used semiconductors.
- Electronic Devices and Circuits Textbook - studylib.net — Comprehensive textbook on electronic devices and circuits, covering semiconductors, diodes, transistors, and amplifiers. ... Comprehensive textbook on electronic devices and circuits, covering semiconductors, diodes, transistors, and amplifiers. Ideal for college-level students. Studylib. Documents Flashcards Chrome extension Login
- Chapter 4. Diode Circuits - Electronic Devices and Circuits, Second ... — Chapter 4 Diode Circuits Full-wave rectifier Chapter Outline The concepts introduced in this chapter are: Regulated power supply and its applications Different types of rectifiers and their performance Different types … - Selection from Electronic Devices and Circuits, Second Edition [Book]
- PDF Chapter IV Diodes and their Applications - Texas A&M University — topologies shown in Figure 4.6. The circuit in Figure 4.6a is fed with a DC current source of 10 mA. Two resistors and a diode are connected at the output. Since the current flows through the combination of the resistors and the diode, the current is expected to flow in the diode's forward direction, assuming a short circuit for the diode. Thus,
- Chapter 4 - Diode Applications - Cambridge University Press & Assessment — The concept of such 'linearizing the diode', as explained with Figures 4.1(a) and 4.1(b), is quite useful to the analysis of the circuits containing diodes. Both the diagrams symbolize the forward current-voltage characteristic curve of a typical diode but at different scales.
- PDF DIODE - Nexperia — in electronic systems. These sub-circuit insights help to address real-world challenges in electronic design. Earlier, we mentioned electric vehicles as one obvious example of an application where new diode technologies are playing a vital, enabling role: in reality, very few electronic systems exist without some form of diode performing a ...
4.2 Online Resources and Datasheets
- LM74202-Q1 40-V, 2.2-A Integrated Ideal Diode with Overvoltage and ... — 8.1 Overview LM74202-Q1 is an ideal diode with integrated back-to-back FETs and enhanced built-in protection circuitry. It provides robust protection for all systems and applications powered from 4.2 V to 40 V. The device integrates reverse battery input, reverse current, overvoltage, undervoltage, overcurrent and short circuit protection.
- 4.2 V ESD Protection Diodes / TVS Diodes Datasheets - Mouser — 4.2 V ESD Protection Diodes / TVS Diodes are available at Mouser Electronics. Mouser offers inventory, pricing, & datasheets for 4.2 V ESD Protection Diodes / TVS Diodes.
- Reading and Understanding an ESD Protection Data Sheet — A few things to point out from looking at the data sheet, the 24-V working voltage, the ESD ratings (IEC61000-4-2), the 1.6-pF or 1.1-pF capacitance, and the packages the devices comes in.
- ESD Protection Diodes / TVS Diodes - Mouser - Mouser Electronics — TVS diodes are an essential component for protecting electronic circuits from voltage spikes, ensuring that sensitive components are not damaged by transient surges. They provide fast and effective protection, especially in environments prone to sudden voltage changes. More...
- PDF Basics of Diodes — Diodes are used in a wide range of equipment for various applications such as rectification, reverse-current blocking, and circuit protection. In addition to silicon (Si) pn diodes, various other types of diodes are available, including Schottky barrier diodes (SBDs), transient voltage suppressor (TVS) diodes (also known as ESD protection ...
- PDF Basics of ESD Protection (TVS) Diodes - Toshiba Electronic Devices ... — ESD protection (TVS) diodes are designed based on constant-voltage diodes, a type of p-n diodes, specifically to protect devices from ESD. The following subsections describe basic p-n diodes and the characteristics unique to ESD protection diodes.
- PDF TVS clamping protection mode - Application note - STMicroelectronics — In other application, electronic circuits need to be protected against repetitive surges. Let's take the following example, where we have to protect the transistor shown in Figure 8 with a TVS having clamping voltage VCL that does not exceed 90 V.
- PDF DIODE - Nexperia — Preface Welcome to the Nexperia Diode Applications Handbook. Like all of our other Design Engineer's Guides, the Diode Handbook is intended to be a practical, comprehensive and up-to-date reference work written by engineers for engineers, sharing expertise, application insights and best practice to help designers optimize their electronic circuits.
- How to select effective ESD protection diodes - EE Times — Key DC specs on protection diode datasheets are breakdown voltage, leakage, and capacitance. They also state a max rating for IEC61000-4-2 to indicate an ESD pulse at a specified level will not damage the diode. However, most datasheets do not have any information about the clamping voltage for high frequency, high current transients such as ESD.
- PDF Characterization of TVS Diodes for ESD Protection Applications — The voltage across the protected circuit is restricted to the clamp voltage of the TVS diode. The ESD protection device is placed before the desired component/circuit to be protected from ESD damage as shown in the figure below.
4.3 Advanced Topics and Research Directions
- Chapter 4. Diodes - Applied Electrical Engineering Fundamentals - UMass — The terms "electronic engineering" and "electronics" refer to the design and use of circuits containing semiconductors, such as diodes, transistors, and integrated circuits (IC's). "Electrical engineering", in contrast, refers to power lines and other circuit applications that historically have not used semiconductors.
- PDF ELEC 2400 Electronic Circuits Chapter 7: Diodes and Circuits - GitHub Pages — Analyzing Diode Circuits. Example 7-2: Assume the diode is ideal, find V. 1. 12 V 5 V. 1. 11 V 10 10 D (1) Assume the operating mode of the diode (either ON or OFF); (2) Replace the diode with corresponding short or open circuit; (3) Find relevant voltages and/or currents; and (4) Check if the assumption in step (1) is correct or not. If it is
- PDF Esd Protection Circuits for Advanced Cmos Technologies — addressed in breadth, covering topics that range from fundamental device physics to circuit design engineering, providing the guidelines needed to develop robust and transparent ESD protection circuits. As the circuit performance has been improved and the bandwidth of circuit interfaces has
- π-Shape ESD Protection Design for Multi-Gbps High-Speed Circuits in ... — The required operating speed of integrated circuits is increasing, and multi-Gbps high-speed CMOS ICs are widely used in digital communication systems [].However, the transistors are weak to electrostatic discharge (ESD) events in CMOS technology [2,3].In order to pass the component-level ESD test [], all integrated circuits should be designed with an on-chip ESD protection circuit.
- PDF Characterization, Modeling, and Design of Esd Protection Circuits — ESD PROTECTION CIRCUITS By STEPHEN G. BEEBE March 1998 Technical Report No. xxxxxxx Prepared under Semiconductor Research Corporation Contract 94-SJ-116 Semiconductor Research Corporation Contract 94-YC-704 Special support provided by ... 2.15 ESD diode protection circuit in a CMOS technology and use of a series
- PDF Basics of Diodes (Types and Overview of Diodes) — Diodes are used in a wide range of equipment for various applications such as rectification, reverse-current blocking, and circuit protection. In addition to silicon (Si) pn diodes, various other types of diodes are available, including Schottky barrier diodes (SBDs), transient voltage suppressor
- PDF Advanced Practical Electronics - ResearchGate — ii Advanced Practical Electronics - Circuits & Systems P Malindi Disclaimer Circuits in this book have been done using CircuitMaker, SmartDraw, Visio and
- PDF Chapter IV Diodes and their Applications - Texas A&M University — topologies shown in Figure 4.6. The circuit in Figure 4.6a is fed with a DC current source of 10 mA. Two resistors and a diode are connected at the output. Since the current flows through the combination of the resistors and the diode, the current is expected to flow in the diode's forward direction, assuming a short circuit for the diode. Thus,
- Semiconductor Devices: Theory and Application - Open Textbook Library — The goal of this text, as its name implies, is to allow the reader to become proficient in the analysis and design of circuits utilizing discrete semiconductor devices. It progresses from basic diodes through bipolar and field effect transistors. The text is intended for use in a first or second year course on semiconductors at the Associate or Baccalaureate level. In order to make effective ...
- PDF Diodes Notes A. Stolp - University of Utah — Other Useful Diode Circuits ECE 2210 Diode Notes p4 Simple limiter circuits can be made with diodes. A common input protection to protect circuit from excessive input voltages such as static electricity. The input to the box marked "sensitive circuit" can't get higher than the positive supply + 0.7V or lower than the negative supply - 0.7V.