LDH40 - High-Speed Switching Diode | Vishay
料号： LDH40 ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $0.12 | $0.12 |
| 10 | $0.1 | $1.00 |
| 100 | $0.08 | $8.00 |
| 500 | $0.06 | $30.00 |
| 1,000 | $0.05 | $50.00 |
LDH40 概述
A switching diode is a semiconductor device that allows current to flow in one direction while blocking it in the reverse direction, with fast recovery characteristics optimized for high-frequency switching. In the hierarchy of electronic components, a switching diode falls under discrete semiconductors, specifically within the diode family, which also includes rectifiers, Zener diodes, and Schottky diodes. Switching diodes are essential in applications such as signal clamping, voltage limiting, and logic gating, where rapid transitions between conducting and non-conducting states are required.
Key features of the LDH40 include a fast reverse recovery time of 4 ns, which minimizes switching losses in high-frequency circuits, and a low forward voltage drop of 1 V at 100 mA, ensuring efficient operation. The device also offers a high reverse breakdown voltage of 80 V, providing adequate margin for typical signal-level voltages. Its DO-35 package is compact and robust, with a power dissipation rating of 500 mW, suitable for low-power applications.
Technically, the LDH40 is fabricated using planar epitaxial technology, which ensures consistent electrical characteristics and high reliability. The device's fast recovery time is achieved through gold doping, which reduces carrier lifetime and accelerates the transition from forward conduction to reverse blocking. This makes the LDH40 particularly effective in high-frequency switching circuits, such as those found in communication equipment and instrumentation.
Typical applications include signal clamping in analog circuits, voltage limiting in protection circuits, and switching in logic gates. The LDH40 is also used in RF detectors and mixers, where its fast recovery and low capacitance are advantageous. In audio equipment, it can be used for signal rectification and envelope detection.
When designing with the LDH40, ensure that the reverse voltage does not exceed the 80 V rating and that the forward current remains within the 300 mA limit. For high-frequency operation, keep lead lengths short to minimize parasitic inductance. The device is RoHS compliant and lead-free, making it suitable for environmentally conscious designs.
直接替换替代料： LDH40 ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
快速对比工具——选择替代料号进行并排对比：
1N4148
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
1N914
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
BAV21
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
LDH40 最大额定值与电气特性
| Diode Type | Switching Diode |
| Maximum Repetitive Peak Reverse Voltage (VRRM) | 80 V |
| Maximum RMS Reverse Voltage (VRMS) | 56 V |
| Maximum DC Blocking Voltage (VDC) | 80 V |
| Maximum Average Forward Rectified Current (IF(AV)) | 300 mA |
| Maximum Peak Forward Surge Current (IFSM) | 2 A |
| Maximum Forward Voltage (VF) | 1 V at 100 mA |
| Maximum Reverse Recovery Time (trr) | 4 ns |
| Maximum Reverse Leakage Current (IR) | 25 nA at 80 V |
| Junction Capacitance (CJ) | 2 pF at 0 V, 1 MHz |
| Power Dissipation (PD) | 500 mW |
| 工作温度范围 | -65°C to +175°C |
| 封装 | DO-35 (DO-204AH) |
| 安装类型 | Through Hole |
| RoHS 状态 | Compliant |
| Lead-Free | Yes |
LDH40 引脚配置
| 引脚 1 | Anode — Anode terminal, current flows in this direction |
| 引脚 2 | Cathode — Cathode terminal, marked with a band |
典型应用
LDH40 适用于 6 应用s: Signal Clamping, Voltage Limiting, Logic Gating, RF Detection, Audio Envelope Detection, Protection Circuits.
Signal Clamping
The LDH40 is used for signal clamping to limit voltage levels in analog circuits. Its fast reverse recovery time (4 ns) ensures minimal distortion of high-frequency signals, while its low forward voltage (1 V at 100 mA) provides precise clamping thresholds. In a typical clamping circuit, the diode is placed in parallel with the signal path, conducting when the voltage exceeds a set level, thereby protecting downstream components from overvoltage. The low junction capacitance (2 pF) minimizes signal attenuation, making it suitable for RF and video applications. Compared to slower diodes, the LDH40 reduces clamping-induced waveform distortion, preserving signal integrity in high-speed data lines.
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Voltage Limiting
In voltage limiting circuits, the LDH40 protects sensitive components by conducting when the voltage exceeds a safe threshold. Its 80 V reverse voltage rating provides adequate headroom for typical low-voltage applications, while its 300 mA forward current handles transient currents without damage. The diode's fast recovery ensures rapid response to overvoltage events, reducing the risk of damage to downstream circuitry. In a typical protection circuit, the LDH40 is connected across the input terminals, shunting excess voltage to ground. Its low leakage current (25 nA) ensures minimal power loss during normal operation, making it suitable for battery-powered devices. The DO-35 package allows easy integration into existing PCB designs.
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Logic Gating
The LDH40 is used in logic gating circuits to implement AND and OR functions using diode-resistor logic. Its fast switching speed (4 ns) enables high-speed logic operations, while its low forward voltage ensures clean logic levels. In a typical diode logic gate, multiple diodes are connected to a common output node, with each diode representing an input. The LDH40's low capacitance (2 pF) reduces propagation delays, making it suitable for high-frequency digital circuits. Compared to discrete logic gates, diode logic using the LDH40 offers a simple and cost-effective solution for basic logic functions. However, it is limited by its lack of gain, so it is often used in combination with amplifiers or buffers.
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RF Detection
The LDH40 is employed in RF detection circuits to demodulate amplitude-modulated signals. Its fast reverse recovery time (4 ns) and low junction capacitance (2 pF) allow it to respond to high-frequency carriers, making it suitable for RF applications up to several hundred MHz. In a typical detector circuit, the diode rectifies the RF signal, producing a DC output proportional to the signal amplitude. The LDH40's low forward voltage (1 V) ensures high sensitivity, while its low leakage current (25 nA) minimizes noise. Compared to Schottky diodes, the LDH40 offers a higher reverse voltage rating, making it more robust in applications with higher voltage transients. Its DO-35 package is suitable for through-hole RF designs.
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Audio Envelope Detection
The LDH40 is used in audio envelope detection circuits to extract the amplitude envelope of audio signals. Its fast response time (4 ns) ensures accurate tracking of signal variations, while its low forward voltage (1 V) provides a linear detection characteristic. In a typical envelope detector, the diode rectifies the audio signal, and a capacitor filters the output to produce a smooth envelope. The LDH40's low capacitance (2 pF) minimizes high-frequency losses, preserving audio quality. Compared to other diodes, the LDH40 offers a good balance of speed and voltage rating, making it suitable for audio processing applications. Its DO-35 package is easy to integrate into audio circuits.
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Protection Circuits
The LDH40 is used in protection circuits to safeguard sensitive components from overvoltage and reverse polarity. Its 80 V reverse voltage rating provides a robust blocking capability, while its 300 mA forward current handles fault currents. In a typical protection circuit, the diode is placed in series or parallel with the load to prevent damage from voltage spikes. The LDH40's fast recovery time (4 ns) ensures rapid response to transients, reducing the risk of component failure. Its low leakage current (25 nA) minimizes power loss during normal operation, making it suitable for energy-efficient designs. The DO-35 package allows easy integration into existing protection circuits.
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推荐产品汇总
工程参考数据： LDH40 ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | 1N4148 | 1N914 | BAV21 |
|---|---|---|---|---|
| Package | DO-35 | DO-35 | DO-35 | DO-35 |
| Brand | Vishay | Vishay | Vishay | Vishay |
| Maximum Reverse Voltage | 80 V | 75 V | 75 V | 200 V |
| Forward Current | 300 mA | 300 mA | 300 mA | 250 mA |
| Reverse Recovery Time | 4 ns | 4 ns | 4 ns | 50 ns |
| Forward Voltage | 1 V at 100 mA | 1 V at 100 mA | 1 V at 100 mA | 1 V at 100 mA |
| Junction Capacitance | 2 pF | 2 pF | 2 pF | 2 pF |
| Power Dissipation | 500 mW | 500 mW | 500 mW | 500 mW |
关键差异点
- Higher reverse voltage rating (80 V) compared to common alternatives （对比 1N4148)
- Fast reverse recovery time (4 ns) for high-speed switching （对比 BAV21)
- Low junction capacitance (2 pF) for RF applications （对比 1N914)
设计说明
For high-frequency applications, keep the leads of the LDH40 as short as possible to minimize parasitic inductance. Use a ground plane beneath the diode to reduce loop area and improve switching performance. The DO-35 package is through-hole, so ensure proper hole sizing and solder fillet for reliable mechanical and electrical connection.
The LDH40 has a power dissipation rating of 500 mW. In continuous operation, ensure that the ambient temperature and PCB layout allow for adequate heat dissipation. For currents near the maximum rating, consider derating based on the thermal resistance of the package and the surrounding environment.
Do not exceed the maximum reverse voltage of 80 V, as this can cause breakdown and permanent damage. Also, avoid exceeding the forward current rating of 300 mA, which can lead to overheating. When using the diode in high-frequency circuits, be aware of its junction capacitance (2 pF) and its effect on signal integrity.
合规信息
RoHS compliant and lead-free per Vishay datasheet. AEC-Q100 not applicable for discrete diodes.
