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Industrial-grade step-down DC-DC converters providing long-term supply guarantee and available in small-reel sales : Routine Requirements in Industrial Applications: Long-Term Supply Guarantee and Small-Lot Sales


ROHM’s step-down DC-DC converters comprise a series of products intended to meet the needs in the industrial markets. The series is designed not only to withstand rigorous operating conditions, but also to answer the demand for increasingly smaller and power-saving devices, in addition to accommodating industrial device-specific conditions, such as small-lot production and a long product service life. To learn more about these key points, we interviewed Mr. Youju Imamura, a field application engineer at ROHM.

- I take it that ROHM offers a series of DC-DC converters designed for “industrial” applications. Could you give us an overview of those converters, numerous as they may be in the total quantity produced?

What I’d like to address, in terms of “industrial” converters, is the series designated with a suffix “LB” attached to the part number, such as “BD9E100FJ-LB”. This is an important caveat in avoiding any misunderstanding because we also make large numbers of ICs capable of accommodating industrial needs in terms of operating temperature range and other conditions.

The current LB products for DC-DC converter ICs are synchronous rectifying step-down types, made up of 16 models of integrated MOSFETs type and 2 controller-type models. To suit a specific application, users can select desired input voltage ranges, output currents, and switching frequencies.

- In a nutshell, in what ways do the LB product differ from other ICs?

In terms of performance, they are designed to withstand rigorous operating and environmental conditions that industrial devices must contend with. Furthermore, they are produced in stable “long-term supply guarantee” and offered for “small-reel” sales, consisting of 250 units per pack.

- Not many manufacturers offer product series specifications covering both long-term supply guarantee and small-reel sales, even though there have been such cases written into agreements with specific customers.

That’s for sure. That being the case, before describing features of DC-DC converters, let me touch upon the reasons why the two items were included in the language of LB product specifications.

First of all, in terms of long-term supply guarantee, as a rule for industrial devices a durability level greater than 10 years is prerequisite. Also, the availability of maintenance boards and components needs to be guaranteed for considerably long periods of time. Therefore, generally Industrial customers do not adopt cutting-edge components with an uncertain future or those which are likely to undergo version changes in a few years or be discontinued fairly soon.

- To be sure, the selection of components for industrial devices gives an impression of being conservative.

There are several underlying reasons for that trend: Even if a given component does not offer overriding advantages, if it provides a high degree of general applicable capability, it enjoys continuing demand, and its track record of being produced in a consistent manner makes it likely that it will continue to be supplied in the future, and such a perception can shape the extent to which the component continues to be produced in years to come. Even then, it is not unusual for an industrial device manufacturer to receive a notice of discontinuance out of the blue from an IC manufacturer for various reasons, resulting in considerable repercussions.


- If the supply of a required component ceases during the production of a device, even in the midst of an guaranteed maintenance service period, what specific trouble arises when such a device is produced in large aggregate quantities?

As a general rule, in the case of an IC manufacturer, in a so-called life-time order the manufacturer books an order covering quantities that the customer is likely to require in the long run, and the manufacturer takes the responsibility to deliver that quantity. This approach, however, requires that the customer build and maintain a stock of the component to cover the needs in the future years. In this sense, the approach, even if necessary, may not be all that preferable.

Also, there have been cases where the manufacturer was unable to fill large-quantity orders or the customer, due to unanticipated circumstances, ran out of stock, resulting in supply bottlenecks. In such a case, the customer must search the distribution chain for stock availability, at the expense of considerable labor and significant risks.

- Is that the reason that industrial device manufacturers, when adopting a DC-DC converter, often demand some kind of guarantee to ensure an adequate supply over a period of time?

Yes, that would be the case. It is for this reason that LB products feature specifications that are referred to as long-term supply guarantee. For industrial device manufacturers, a long-term supply is an essential requirement, and basically they need a guarantee to assure that. It goes without saying that for quite some time we have dealt with the supply situation on an individual account basis. That said, we thought that as long as we pitched our products as industrial application products, the provision of long-term supply guarantee would be an obvious element to be written into the agreement. It goes without saying that a stable supply, in addition to a long-term supply, is mandatory.

- That being the case, what is the reason for the other important requirement, small-reel sales?

In industrial devices, even when the aggregate volume is large it is not unusual that some products are made in quantities only in hundreds of units. In relation to that, although I’m not happy to admit it, IC manufacturers sell reels in quantities that amount to thousands of units, equivalent to years of the customer’s needs, by far exceeding the needs. That means that even when the customer wanted to adopt a given IC product, the quantity issue prevents him from buying it. To address this situation, we are offering LB products in small reels, in 250 unit per reel quantities.

- In other words, is the small-lot sales offering small reels also a program designed to provide improved convenience based on the characteristics of industrial device customers even in situations where the aggregate volume is large?

You seem to understand exactly where we are coming from. At present ROHM is working hard at industrial markets. I believe that it is crucial for us to respond to the characteristics of the industrial device markets, in addition to providing ICs with performance features that are well-attuned to the demands of the industrial markets.

Turning the tables, may I make a comment?

- Yes, please, of course.

The reason that we have built long-term supply guarantee and small-reel sales in the LB products specifications for industrial applications is not only to answer existing requirements, but also to offer a solution to power saving and down-sizing needs that have become imperatives for industrial devices as well.

- Do you mean that long-time supply guarantee and small-reel sales are linked to the power saving and down-sizing needs for industrial devices?

You mentioned earlier that the selection of components for industrial devices gives an impression of being a conservative tendency. Could you recall the reasons for that tendency? The reason is not a performance or technological one in that selecting the so-called “components that are familiar to you” makes it easy to procure even in small quantities due to the availability of continuing supply and distribution, but due to the fact that the ease of acquisition, which is not an essential attribute, proves to be a significant constraint.

In other words, high-efficiency, small-size DC-DC converter ICs providing extra advantages of a stable long-term supply guarantee while being available in small-reel sales permit customers of industrial devices to adopt it with a peace of mind, at the same time helping to attain objectives of power savings and down-sizing.

- Precisely. When we talk about ICs, we tend to focus on IC function and performance aspects. However, it is clear that even when the aggregate sales are large, convenience, supply, and terms of procurement are also critical factors.
That being the case, I’d like to ask you questions on what specific features and performance are provided by LB series DC-DC converters.

※Small-reel sales are available on a case by case basis. If interested, please contact us on an individual basis.

Information on Downloading Technical Documents

Downloadable materials, including lecture materials from ROHM-sponsored seminars and a selection guide for DC-DC converters, are now available.

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Download Technical Documents

Downloadable materials, including lecture materials from ROHM-sponsored seminars and a selection guide for DC-DC converters, are now available.

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