Kingtronics Blog

The equivalent series resistance is the resistive element (R1) of the quartz crystal equivalent circuit. (see Equivalent Circuit below) This resistance represents the equivalent impedance of the crystal at natural resonant frequency (series resonance) ESR is measured by a Crystal Impedance (CI) meter.

ESR values are generally stated as maximum values expressed in ohms. The ESR values vary with frequency, mode of operation, holder type, crystal plate size, electrode size, and mounting structure.

It is worth noting that the ESR value at a given frequency for an AT- strip crystal design is generally higher than that of the standard (round blank) design. This becomes more significant at lower frequencies. When transitioning from a series resonant through-hole HC-49/U type crystal to a smaller surface mount type utilizing an AT-strip crystal, some consideration may be given to the difference in the ESR values produced by different cuts.

The ESR becomes critical when resistance values reach a point were the oscillator circuit cannot adequately drive the crystal. Sluggish start-up or unwanted modes of operation may result.

Equivalent Circuit:

The equivalent circuit (shown in Figure A) depicts electrical activity of a quartz crystal unit operating at its natural resonant frequency. The shunt capacitance (Co), represents the capacitance of the crystal electrodes plus the capacitance of the holder and leads. R1, C1, and L1 compose the "motional arm" of the crystal, and are referred to as the motional parameters. The motional inductance (L1) represents the vibrating mass of the crystal unit. The motional capacitance (C1) represents the elasticity of the quartz, and the resistance (R1), represents bulk losses occurring within the quartz.

Schottky rectifiers have been used in the power supply industry for approximately 15 years. During this time, significant fiction as well as fact has been associated with this type of rectifier. The primary assets of Schottky devices are switching speeds approaching zero-time and very low forward voltage drop (VF). This combination makes Schottky barrier rectifiers ideal for the output stages of switching power supplies. On the negative side, Schottky devices are also known for limited high-temperature operation, high leakage and limited voltage range BVR. Though these limitations exist, they are quantifiable and controllable, allowing wide application of these devices in switch mode power supplies.

High leakage, when associated with standard P-N junction rectifiers, usually indicates “badness,” implying poor reliability. In a Schottky device, leakage at high temperature(75 °C and greater) is often on the order to several milliamps, depending on chip size. In the case of Schottky barrier rectifiers, high-temperature leakage and forward voltage drop are controlled by two primary factors: the size of the chip’s active area and the barrier height (φB).

The EKT Series is a high temperature version of Kingtronics's solid tantalum chip family that offers optimal performance in applications with operating temperatures of up to 125° C. Advancements in materials and testing have allowed for the introduction of this series which delivers a reliability level of 0.5% per 1000 hours at rated voltage at rated temperature. This series is available in five standard EIA case sizes with RoHSCompliant/100% matte tin finish lead terminations as standard.

Other termination options include 90Sn/10Pb finishes and gold for conductive adhesive attachment processes. Capacitance values range from . 0.33uF - 470uF, in voltage ratings from 4 to 50 volts.

Kingtronics has developed an innovative construction platform that incorporates multiple capacitor elements,in parallel, inside a single package. This unique assembly, combined with Kingtronics’s superior processing technology, provides the best combination of high CV, low ESR, and small size in a user friendly, molded, surface mount package.

The fundamental electrical properties of multilayer ceramic capacitors are as follows:

Polarity: Multilayer ceramic capacitors are not polar, and may be used with DC voltage applied in either direction.

Rated Voltage: This term refers to the maximum con tinuous DC working voltage permissible across the entire operating temperature range. Multilayer ceramic capacitors are not extremely sensitive to voltage, and brief applications of voltage above rated will not result in immediate failure. However, reliability will be reduced by exposure to sustained voltages above rated.

Like all other practical capacitors, multilayer ceramic capacitors also have resistance and inductance. A simplified schematic for the equivalent circuit is shown in Figure 1. Other significant electrical characteristics resulting from these additional properties are as follows：

Impedance: Since the parallel resistance (Rp) normally very high, the total impedance of the capacitor is ：

The variation of a capacitor’s impedance with frequency determines its effectiveness in many applications.

Quartz crystals used in filters and oscillators in electronic circuits are renowned for their performance, stability, frequency tolerance and their high Q. Yet they do change their frequency very slightly with time in a process known as ageing. Although the frequency variations are small by many standards, they are permanent and may have an effect in some applications where the frequency is of great importance. As a result manufacturing techniques take account of this to reduce the effects of ageing in these crystals as far as possible.

Ageing is caused by a number of interrelated factors. These include internal contamination, excessive drive level, surface change of the crystal, various thermal effects, wire fatigue and frictional wear. The level of ageing can be minimised in a number of ways. During manufacture they should be encapsulated in an inert gas environment, the ensuring should have a good seal so that other gases do not enter. Also the final stages of the preparation of the crystal blank must be prepared as finely as possible. Rather than lapping the blank to bring it to the right dimensions, chemical etching is used. In this way the minimum disruption is caused to the crystal lattice, and this reduces the ingress of contaminants over time that will cause ageing.

The design of the circuit in which the crystal will be used also has an effect. By keeping the drive levels low again the crystal ageing will be less.

Features

• - Operating temperature Range: -55℃~+125℃ (>80℃ with rated volted darating)
• - Laser-markec Case
• - Capacitance tolerance: +/-20%; +/-10% (for special order)
• - DC leakage at 25℃: Io≤0.01CRVR or 0.5μA (Whichever is greater)

Low ESR values allow for more efficient filtering in DC-to-DC conversion applications, while the devices' ability to handle high currents is key in microprocessor bulk energy storage applications. Kingtronics ( www.kingtronics.com)EKT Series Low ESR (Low Equivalent Series Resistance) Chip Tantalum Capacitors are intended for applications in telecom, automotive, computer, industrial, commercial, medical, and avionics end systems.
 
In addition to providing very low ESR values and a high ripple current handling capability, the new Tantalum Capacitors feature a proven solid tantalum construction that ensures long-term reliability. Outstanding stability over time and temperature further enhances the EKT Series Low ESR Chip Tantalum Capacitors devices' performance and reliability.

Reverse Voltage - 20 to 40 Volts Forward Current - 3.0 Amperes

FEATURES

• Plastic package has Underwriters Laboratory Flammability Classification 94V-0
• Metal silicon junction, majority carrier conduction
• Guardring for over voltage protection
• Low power loss, high erriciency
• High current capability, low forward voltage drop
• High surge capability
• For use in low voltage, high frequency inverters, free wheeling, and polarity protection applications
• High temperature soldering guaranteed:
  250℃ /10 seconds, 0.375”(9.5mm) lead length,5 lbs. (2.3kg) tension

MLCC consists of a conducting material and electrodes. To manufacture a chip-type SMT and achieve miniaturization, high density and high efficiency, ceramic condensers are used.

WTC’s MLCC is made by NPO, X7R and Y5V dielectric material and which provides product with high electrical precision, stability and reliability.

Storage and Operating Condition

(1) To store products at 5℃ to 40℃ ambient temperature and 20% to 70%. related humidity conditions.
(2) The product is recommended to be used within one year after shipment. Check solderability in case of shelf life extension is needed.

Cautions:

a. Don’t store products in a corrosive environment such as sulfide, chloride gas, or acid. It may cause oxidization of electrode, which easily be resulted in poor soldering.
b. To store products on the shelf and avoid exposure to moisture.
c. Don’t expose products to excessive shock, vibration, direct sunlight and so on.

A Surge Arrestor is installed between communication equipment and coaxial cable connector or between two communication equipments to protect communication equipment from damage caused by transient state voltage formed by lightning induction. It adopts quarter-wave technology, is designed according to VSW theory and frequency spectrum of lightning wave. It has features of quick reaction, big current passing capacity, wide frequency band, low VSWR, low insertion loss, easy installation and free maintenance. It can be used to meet protection requirements of various communication equipments and lightning sensitivity.

Surge arrestor series

Kingtronics sell 2-Electrode arresters and 3-Electrode arresters. 2-Electrode arresters and 3-Electrode arresters have many different kinds of types, for the detailed information please link the following Data Sheet. They will take you to www.kingtronics.com.

Dear Customer:

Wish you good business !!

As you know Chinese Lunar New Year is coming soon, most of Chinese manufacturers will have a long holiday.

But please don’t worry on this holiday issue, we Kingtronics will work as normal during this Chinese Traditional  Spring Festival.

So, please feel free to contact with our sales department by email and keep sending us orders and inquiries. We will get feedback to you as fast as normal days.

Thanks a lot for your attentions.

Wish you all the best !!

Kingtronics International Company

info@kingtronics.com

www.kingtronics.com