Ericsson's Floated Inserted Pin Simplifies The Utilization Of High-Power Surface Mount Modules

The number of functionalities integrated per board is permanently increasing, making board space very critical. Several companies are migrating their manufacturing processes to drastically reduce the quantity of conventional through-hole components. Board designers are therefore requiring power modules manufacturers to provide surface mountable power modules that have the same performances as their through-hole ones, which in the case of high-power DC/DC converters is a very challenging issue. Guaranteeing that the interconnection-resistance of surface mount connectors are equal to or better than conventional pins is a technical challenge that Ericsson has addressed by developing a specific surface-mount connector able to carry high current while keeping interconnection-resistance very low and maintaining a robust mechanical termination.

Prime customers are those using information and telecommunication technologies such as datacenters, routers, and telecom equipment, but also a large range of customers who need to power their application from a 48V line and require a high-efficiency, intermediate bus voltage of 12V. Specifically, those requiring high-density boards - ones requiring surface mount components only.

Simplifying the manufacturing process by using only surface mount components reduces the number of manufacturing steps, shortening manufacturing cycles, and by removing second pass soldering for through-hole components, reduce cost.
The PKM4000B SI footprint is a standard quarter-brick, and is 100% compatible with similar products available on the market. With a typical efficiency of 96% at half load and 48V input this product contributes to reduce overall power consumption. Ericsson's Floated Inserted Pin (FIP) technology guarantees high co-planarity and a wide soldering surface, reducing contact resistance to a minimum.

The module includes operational protection for over temperature protection (OTP), output over voltage protection (OVP), and output short-circuit protection. Additionally, optional latching OTP and OVP are available on request. With a maximum height of 11.2mm, the PKM4000B SI is compatible with reduce board-space applications or cold-wall equipments requiring low height. According to Telcordia SR332, and calculated at full power and an operating at +40 degrees C, the PKM4000B SI has an excellent MTBF of 1.1 million hours

The PKM4000B SI benefits from Ericsson's market-proven surface-mounted expertise and its heritage goes back to the original MacroDens and PKR of which 45 million have been shipped to market. With 80 percent of that volume being surface-mount and the addition of sixteenth brick PKU and eight-brick PKB surface mountable series using Ericsson's FIP, concept Ericsson has demonstrated that the technology brings real end-user benefits and is expandable to higher power modules.

As part of Ericsson's designed for manufacturing (DFM) process, the FIP concept takes into consideration the entire process, from manufacturing to final assembly by the customer. Indeed, By taking into consideration end-user's manufacturing constraints from the beginning, Ericsson's DfM process has made it possible to develop surface-mount modules that comply with even the most demanding manufacturing processes. The layout of the products has been carefully optimized to facilitate pick-and-place, simplifying manufacturing operations.

The modules' FIP concept ensures that all the connecting pins remain in place and are aligned during second or third reflow soldering. The pins are also manufactured with very tight tolerances, guaranteeing co-planarity and mechanical accuracy.
Ericsson Power Modules' FIP concept is based on very accurately tooled pins that are inserted and aligned during the original assembly process. When a PKM4000B SI module is assembled on the final board, during lead-free soldering reflow, the pins remain aligned in the plated through-hole of the PKM4000B SI and self-adjust to guarantee excellent interconnection between the two solder pads. This ensures high reliability and host equipment availability.

Many modules already released by several manufacturers use pins such as box-pins or cylinder-pins that were originally designed for lower-mass modules (such as point-of-load). Although such pins are perfectly suitable for light components (Ericsson also uses box-pins in some of its point-of-load modules), in the case of greater mass modules, if the pins are not mechanically secured in the PCB there is a significant risk that the pins may move during assembly and reflow, with consequences ranging from short-circuit to total disconnection. So the assembly advantage of FIP for the final user is very significant, as it guarantees high stability and reliability when assembling heavier surface-mount modules.

To reduce conducted and switching losses, the PKM4000B is built on a high copper density PCB using low resistive MOSFETs and its use of large contact area proprietary FIP technology reduces interconnection losses when the module is connected to end-users' boards. Based on millions of products shipped to market, and the market success encountered by Ericsson's surface mountable PKU sixteenth brick and PKB eighth-brick, this technology is fully optimized for high-power surface mount modules.