App note: Through-Hole versus SMD components

App note from Vishay on the advantages of using Through-Hole mounting. Link here (PDF)

Most electronic gadgets are designed to interface with humans, and we humans are very abusive to most electronic devices. We drop them, poke them, open and close them, and in general feed stuff into and out of them.

It is well understood that a through-hole connection to the PCB is mechanically stronger than most surface-mount connections. By comparison, the strength of the bond that holds a surface-mount component to the PCB is limited to the strength of the solder joint that holds it to the surface of the laminate. As parts get smaller, so does the amount of solder and thus the strength of the bond.

App note: Thermal management in surface-mounted resistor applications


App note from Vishay on PCB thermal management specifically on components like SMD resistors, where if allowed a design change (e.g. change in SMD size or change in more heat tolarant ones) must be implemented in order to squeeze more thermal capability. Link here (PDF)

Thermal management is becoming more important as the density of electronic components in modern printed circuit boards (PCBs), as well as the applied power, continues to increase. Both factors lead to higher temperatures of individual components and of the entire assembly. However, every electrical component in an assembly has to be used within its prescribed operating temperature limits due to its material properties and reliability aspects. In this application note, experimental results are provided in order to prevent overheating of electronic devices such as surface-mount resistors.

App note: Potentiometers and trimmers


App note from Vishay on variable resistors primer. Link here (PDF)

A potentiometer is a mechanically actuated variable resistor with three terminals. Two of the terminals are linked to the ends of the resistive element and the third is connected to a mobile contact moving over the resistive track. The output voltage becomes a function of the position of this contact. Potentiometer is advised to be used as a voltage divider.

App note: Application of leaded resistors in energy meters


App note from Vishay about energy meter circuits and the use of leaded resistors on them. Link here (PDF)

An electric meter or energy meter is a device that measures the amount of electrical energy supplied to a residence or business. It is also known as (k)Wh meter. The main unit of measurement in the electricity meter is the kilowatt-hour which is equal to the amount of energy used by a load of one kW over a period of one hour.

App note: Overcurrent protection with Thin Film resistors technology


A technical note about Thin Film fuses from Vishay. Link here (PDF)

Thin film technology is an established technology for high-grade passive components, which has been proved and refined over decades. Its advantages in terms of accuracy, repeatability and stability are appreciated in mass production for billions of thin film resistors every year. Chip fuses produced in thin film technology now deliver similarly predictable properties in terms of the stability and repeatability of the fusing characteristic. With this proven technology embodied in next-generation safety devices for overcurrent protection, power electronics designers can achieve higher levels of safety and performance in new product designs.

App note: Solid state relays input resistor selection


SSR or solid state relays input resistor recommendation app note from Vishay. Link here (PDF)

Solid state relays (SSRs) are commonly driven by TTL or buffered CMOS logic gates. These gates, when used to sink current, provide adequate drive for SSRs. An open-collector output is not required to drive the SSRs, but it can be useful to perform a logic OR function.

A quick recommendation for 5 V power supply operation of most SSRs is to use a 560 ohm resistor. This combination provides an LED current range of 5 mA to 9 mA, thereby optimizing LED current, surge capability, and turn-on/off times. This calculation has taken into consideration power supply variations, temperature variations from – 40 °C to + 85 °C, and manufacturing variations. It uses a 10 % tolerance, 300 ppm/°C input resistor. Likewise, for operation to only 70 °C, a 680 ohm resistor would suffice.

App note: EPIC: Electro-Pyrotechnic Initiator Chip Resistor


An application note on Vishay’s electro-pyrotechnic resistor chip made from thin film technology. Link here (PDF)

In this paper we will show how the EPIC’s thin film construction is unique in providing pyrotechnic engineers with outstanding performances in terms of firing energy, firing time, reproducibility and reliability, easy set up, no fire/all fire ratio, assembly, versatility, etc.

App note: Using Vishay infrared receivers in a Wi-Fi environment


2.4Ghz and 5 Ghz Wi-fi signals can sometimes affect IR receivers, here’s Vishay’s app note about them. Link here (PDF)

In recent years, Wi-Fi connectivity has penetrated most consumer electronic devices used for media reproduction. New TVs, satellite receiver and cable boxes, and streaming devices are more often than not built with Wi-Fi capabilities at multiple frequencies: 2.4 GHz and 5 GHz. Most of these appliances continue to support an infrared (IR)-based remote control link, often even when the device also supports a newer RF-based remote control.
IR remote control receivers are built with highly sensitive wideband input stages and are able to detect signals near the noise level of their circuitry. In noisy environments, such as with both low- and high-frequency electromagnetic interference (EMI), the receiver may be noise-triggered, typically manifesting itself in the form of spurious pulses at its output. Most Vishay IR receiver packages are designed with metal shields to effectively guard the receiver against low-frequency EMI. However, these metal shields have not proven entirely satisfactory against high-frequency EMI in the GHz range used for Wi-Fi.

App note: Solid state relay parallel and DC operation


Parallel two solid state relays for improved current handling and avoiding imbalance of load distribution are discussed in this an app note from Vishay. Link here (PDF)

Vishay solid state relay (SSR) outputs can be wired in parallel enabling the user to benefit from lower on-resistance and higher load currents for AC/DC switching applications. This technique is also useful to compensate for load current derating with increased ambient temperature, to minimize heat from output power dissipation, and for circuits that require redundancy. Also, many of Vishay SPST SSRs provide a center tap so that internal MOSFET switches can be paralleled for DC – only switching applications.