Chip solid tantalum electrolysis with large capaci

Progress in chip solid tantalum electrolytic capacitors with large capacity, low impedance and high ripple current resistance

Chinese figure classification No.: tm535.1 document identification code: a Article No.: (1999) the progress in improving the impedance frequency characteristics in the high frequency range by using conductive functional polymer polypyrrole instead of MnO2 as the cathode material of chip solid tantalum electrolytic containers has been introduced in document [1]. However, in many electronic devices, such as portable mobile, notebook computers, dc/dc converters of switching power supply, chip solid tantalum electrolytic capacitors are required not only to have excellent high-frequency and low impedance performance, but also to have large capacitance and high ripple current resistance. Japan has developed a new type of capacitor. In addition to maintaining the original characteristics of high frequency and low impedance, the 7343 chip solid tantalum electrolytic capacitor has reached 2 Improve the safety and reliability of cable product operation "5 v/330 μ F，4 V/220 μ F level, the equivalent series resistance R is 55 m Ω, and the effective value of allowable ripple current at 100 kHz is 1900 ma

microprocessors in personal computers are developing towards high clock frequency, low power supply voltage and high integration. As the load changes rapidly and the load current increases, the capacitor is required to have the characteristics of low impedance, miniaturization and large capacity

in various electronic equipment, dc/dc converters for switching power supply are developing towards high-frequency and miniaturization of switching frequency. Capacitors are required to have the characteristics of high allowable ripple current, low impedance, small size and large capacity

personal computers, as multimedia electronic devices, are developing very rapidly at home and abroad. Most of the microprocessors are Pentium type of Intel company in the United States, which is characterized by lower power supply voltage and higher power supply current (see Table 1). During operation, the devices carried in the microprocessor repeatedly "turn on/off" through software operation. For the power supply, the sharp change of load will affect the stability of power supply. The use of low impedance and large capacity electrolytic capacitors in the power supply circuit can reduce the amplitude of power supply voltage change and mitigate the impact of power supply voltage when the load changes sharply

if a common chip tantalum electrolytic capacitor is assembled in the above circuit, multiple parallel connection is required, which is difficult to meet the requirements of miniaturization and cost reduction. If a new type of large capacity and low impedance chip tantalum electrolytic capacitor is used, the requirements are met. Table 1 Pentium microprocessor power supply voltage and current model clock frequency/mhz power supply current/a power supply voltage/vpentium60 ~ 2004 3.5 ~ 3.525 MMX penti helps industrial development um150 ~ 2505.7 chip 2.8, i/o circuit 3.3pentium pro150 ~ 25012.4 chip 2.1 ~ 3.5, i/o circuit 3.3pentium Ⅱ 200 ~ 50014 chip 1.8 ~ 3.5, i/o circuit 3.32 performance and characteristics [2, 3, 5] large capacity, low impedance The production process and working principle of the chip tantalum electrolytic capacitor with high ripple current resistance are exactly the same as those introduced in reference [1], except that the tantalum powder material and enabling process are slightly different. In terms of shape, structure and size, in order to have better interchangeability with the existing chip solid tantalum electrolytic capacitor, the international general eia535 standard (as shown in Figure 1 and table 2) is fully adopted. The rated working voltage and capacitance are shown in Table 3. Table 2 Outline dimensions of large capacity capacitor MM model lw1w2hz6032 (c) 6.03.21.82.51.37343 (d) 7.34.32.42.81.3 Figure 1 outline structure of large capacity capacitor Table 3 rated working voltage and capacitance C of large capacity capacitor/μ Fvr/v2.54.06.31015---c22---c33---c47--cd68-c-d100---d150--d-220-d--330d--- this large capacity low impedance chip solid tantalum electrolytic capacitor has the following outstanding characteristics

2.1 there is a small equivalent series resistance in the high frequency range

at 100 kHz, R is about 55 m Ω, which is less than 1/10 of aluminum electrolytic capacitor and 1/2 ~ 1/5 of general tantalum solid electrolytic capacitor. Figure 2 shows 10 v/100 μ F R-F characteristic curve of various solid tantalum electrolytic capacitors, ＃ 1 refers to tantalum electrolysis 2 refers to large capacity tantalum electrolysis 3 is a capacitor with conductive polymer polypyrrole as cathode. It is clear from the comparison that only 3 has good R-F characteristics

2.2 miniaturization and large capacity

under the condition of the same capacitance, its volume is less than 1/10 of aluminum electrolytic capacitor and less than 1/2 of ceramic capacitor. Fig. 2 R-F characteristics of three kinds of solid tantalum electrolytic capacitors 2.3 anti high ripple plastic granulator equipment causes serious environmental pollution. As we all know, the ripple current is related to the heating of the capacitor. The AC active power P generated by the capacitor is equal to the product of the square I2 of the ripple current and the equivalent series resistance R. Because the R of the new capacitor is small, it is allowed to pass through a large ripple current when the surface temperature rise of the capacitor is the same. When the surface temperature of the capacitor rises by 5 ℃, the effective value of the ripple current of the new capacitor is about 4 times that of the general solid tantalum electrolytic capacitor and more than 10 times that of the aluminum electrolytic capacitor

2.4 excellent self-healing (repair) and flame retardancy

when the capacitor is subjected to excessive mechanical or electrical stress, resulting in small defects in the Ta2O5 dielectric layer, the local temperature rises due to large leakage flow. Conductive