Using integrated passive devices in micromodule SIP

Last Update Time: 2018-11-22 10:20:19

Integrated passive devices are nothing new in our industry - they have a long history and are well known. In fact, ADI has produced such components for the market in the past. When independent discrete passive devices or integrated passive networks are included as part of the chipset, careful design and management are needed for considerations such as wiring parasitic effect, device compatibility and circuit board assembly. Although integrated passive devices continue to play an important role in the industry, their most important value can only be realized when they are integrated into system-level packaging applications.

A few years ago, ADI launched the new integrated passive technology plan (iPassives). ADI aims to provide passive components such as diodes, resistors, inductors and capacitors through this project, so as to cover the design of signal chains more broadly, while overcoming the limitations and complexities of existing passive component methods. ADI's customer base's need for more complete solutions with efficient spatial dimensions has also driven the development of this program. From the designer's point of view, iPassives can be regarded as a flexible design tool that can design system solutions with the best performance and robustness of the same kind in a very short development cycle. ADI has many signal conditioning IC, and our unique silicon manufacturing process enables these IC to achieve excellent performance. ADI can make full use of the diversity of its existing products to produce Plug and Play systems with excellent performance characteristics without developing highly complex integration processes. In highly customizable networks, the integrated passive technology is closely integrated with all these existing technologies, and the system-level packaging technology is used to encapsulate them. Thus, the fully authenticated, tested and characterized mu Module < devices can be created. The system that used board level solution can now be simplified into a single device. From our customers'point of view, they can now get complete solutions with excellent out-of-the-box performance, shorten the development cycle and save costs, all of which are implemented in very compact packages.

Passive devices can be used alone, in series or in parallel. They are analog signal processing (RLC for amplification, attenuation, coupling, tuning and filtering), digital signal processing (pull-up resistance, pull-down resistance and impedance matching resistance), EMI suppression (LC noise suppression) and power management (R for current detection and limitation, LC). An important component of energy accumulation.

Limitations of discrete components

Passive components used to be discrete, which meant they were manufactured separately and connected in the circuit by wires or power rails on printed circuit boards (PCBs). Over time, they evolve along three paths: smaller size, lower cost and higher performance. These developments are now mature and optimized, but occupancy and height dimensions mean that discrete passive components always limit the effectiveness of efforts to reduce the size and size of the overall solution. Passive devices usually account for more than 80% of the bill of materials in one application, about 60% of the circuit board area, and about 20% of the total component expenditure. These factors bring together a very complex inventory control and storage challenges.

In essence, discrete devices are separate components. Although there may be some ways to ensure that components can be selected from certain process batches, each component still has a high degree of uniqueness. However, when a very matching component is needed, this is a notable drawback. For devices that need to be matched, the uniqueness and difference between components can lead to errors, thus reducing the circuit performance of time zero. In addition, the performance degradation is always worse and worse in the operating temperature range and service life of the circuit.

Another disadvantage of discrete passive devices is that the assembly and wiring of each component is time-consuming and takes up a lot of space. These elements are connected by welding process and are usually assembled via through hole or surface mount packaging technology (SMT). Through-hole is an old assembly technology. It inserts lead devices into PCB holes. Any excess lead length will be bent and removed. The lead of the device will be connected to PCB interconnection power rail by wave soldering. The surface mount package helps to achieve smaller passive components. In this case, the PCB is etched to mount the connection pattern, the solder paste is covered on the pattern, and the SMT element is positioned and placed by the SMT mounter. The PCB is then soldered by reflow soldering (during which solder paste is liquefied and electrical connections are established), and when cooled, solder paste solidifies and SMT components are mechanically connected to the PCB. The main problem with these two assembly technologies is that the welding process may be very unreliable, which is increasingly worrying in industries where defect targets are several parts per million. Several factors are very important in ensuring the reliability of solder joints: the actual composition of solder paste (which is basically lead-free now, so the reliability is reduced), the mechanical stability in reflow soldering process (mechanical vibration can dry solder joints), and the purity of solder paste (any contaminant can negatively affect the reliability of solder joints). Ring, and the time and temperature in the reflow process. The speed of solder paste heating, the uniformity of actual temperature and temperature, and the time of solder paste heating are all very important. Any of these changes may cause damage to the bonding pads or holes, or may also cause mechanical stress on the device, which may lead to failure over time.