Programmable integrated circuits (ICs) are critical components in countless industrial and consumer products. Their unique flexibility and capability to store and deliver complex information and instructions make them invaluable for producing state-of-the-art electronics in highly competitive markets.
Programmable ICs also make demands on the manufacturers who use them. There is an incredible array of programmable ICs from a wide range of vendors, all containing different design parameters that affect the capability of a company to customize programmable IC configuration.
Manufacturers face the juggling act of assessing quality and cost factors with each IC iteration, and predicting product life cycles and changes and the ramifications on the manufacturing floor. How will these changes affect production throughput? Is it going to entail changes in labor or equipment? What will it mean for inventory management? All these factors create a complex equation requiring vigorous management for programmable ICs.
Traditionally, programmable ICs have been programmed away from the production line, either in-house with off-line programming equipment or through third-party shops that program and deliver specific types and quantities of devices. But as companies continuously reassess their process management, some look at other options for programmable ICs that bring the devices closer to the production process.
These strategies offer potential benefits. Each option, however, comes with a set of pros and cons to weigh very carefully. Failure to do so makes the task of integrating programmable ICs into the production line even more complicated, resulting in serious consequences for products and manufacturers.
Usually manufacturers have one goal in mind when they suggest alternative approaches for dealing with programmable ICs: They want to integrate programming into the assembly process, streamlining production and eliminating a management burden. They also believe that a more integrated process will reduce work-in-process (WIP) inventory.
There are four methods of handling programmable ICs: on-board programming, in-circuit programming, outsourcing and internal off-line programming. Each method has advantages and disadvantages.
On-Board Programming
On-board programming uses off-board hardware and software to program a device installed on the printed circuit board (PCB). Access to the programmable device(s) typically is through a serial test access port on the PCB, but also may be through a dedicated parallel interface. The manufacturer can leave blank devices on a PCB until the end of a production line, then program them and perform a functional test just before integrating the board into a final product or system.
This process is highly integrated with the production line. There is no separate off-line process and no extra inventory management for programmed parts. In certain situations¾ primarily with memory devices¾ on-board programming accommodates just-in-time code updates.
For example, suppose a cellular telephone manufacturer has implemented on-board programming. The phones could be assembled, tested and customized with the latest enhancements for a product. Perhaps region-specific language and other custom information could be added at the end of the production process. With this capability, you could provide better value for your customer.
On the face of it, on-board programming may seem an elegant solution. But there are many issues involving device design and location that can prevent effective, efficient implementation.
Depending on what kind of programmable IC is used and how the board is designed, it can be difficult to access the programmable device. You also need to look very carefully at how on-board programming time affects the beat rate of the production line.
Programming time can be very long, especially when serial access is used. If you need extra equipment for the on-board programming to keep pace with the line, the actual cost may exceed the savings and efficiencies on-board programming was meant to achieve.
In-Circuit Programming
In-circuit programming typically is an option to in-circuit board-test systems, also called automatic test equipment (ATE). For a significant price, some board-test equipment vendors permit programming along with testing using the same bed-of-nails test fixture.
Again, there are some manufacturing environments where in-circuit programming makes sense. If you already have board-test equipment in place, consider adding the programming option since the equipment already is integrated into the assembly line.
However, there are drawbacks. In-circuit programming works for flash memory, but it is not well-suited for the more complex programming algorithms associated with many logic and microcontroller devices so its flexibility is very limited. In-circuit programming also may require that you become an expert in device programming algorithms and revisions, since usually these programming aspects are not supported by the ATE vendor.
As in on-board programming, you must weigh the time required for in-circuit programming against the beat rate of the line. If the test time leaves room for programming and still meets the beat rate, then it is an attractive option. But that option could quickly become a bottleneck if different devices—such as tomorrow’s product with two or four times the amount of memory requiring greater programming times—come on-line.
Outsourcing
Outsourcing is one of the most commonly accepted methods of dealing with programmable ICs. The convenience of buying and shipping parts to a programming-services vendor or having a distributor program them for you can be a distinct plus. There is no management of an additional programming process or no capital investment required. If the programming services vendor is reliable, the quality of devices is guaranteed, providing high yields and quality products.
But there are disadvantages. While avoiding an additional management process, if you buy devices and ship them out to be programmed, you must be assured of the quality controls maintained by a programming services vendor.
If you buy a complete package where a vendor purchases and programs the devices, it is difficult to “unbundle” devices from the programming service to compare individual costs. Who pays for reject devices may become an issue. There also are vendor relationships to maintain, communications to keep open, and delivery requirements to continuously monitor.
Outsourcing also can substantially increase the complexity of procurement management and planning. Now you must order as many device types as required, multiplied by the number of data files used per device.
For instance, one telecom switch manufacturer has more than 1,200 active data files to manage. This management issue becomes even more difficult when the released data file changes frequently, potentially causing the manufacturer to scrap the programmed device in the supply pipeline.
Off-Line Programming
This leads us back to internal off-line programming solutions, traditionally the approach taken most often by manufacturers. The benefits of doing your own programming in-house are many:
You closely monitor the cost and quality of devices, with high yields and quick turnaround on reprogramming.
A wide variety of programming equipment fits almost any size company and any kind of product, from low-end production programmers to high-capacity, high-speed machines that handle and program tens of thousands of devices¾ even fine-pitch parts¾ each day.
A wide array of device media, such as trays, tubes and tape-and-reel, is available for transferring programmed devices to the assembly line.
Control of the programming is in your hands, so good parts can be delivered to the line on time.
Because you have a wide range of programming products to pick from, you design enough capacity and flexibility into a system so the assembly line is never shut down.
As in the other choices, though, there are issues that require careful consideration. Internal off-line programming has to be managed. This requires a management process for labor, capital expense and quality concerns.
While current technology provides solutions, you still must pay attention to the processes of lead integrity and ESD stemming from human handling. Programmers must be maintained and inventories of blank and programmed devices managed.
Conclusions
The issues inherent in each approach require you to understand how all these issues may impact your operations capability. While integrated programming methods have the obvious appeal of process integration and reduction of WIP, some of the issues that they present may make them an unrealistic alternative for many manufacturing operations.
Programmable ICs make possible innumerable electronic products on the market, but they have unique requirements because of their algorithms and data formats. There is a diversity of devices from many manufacturers, and design and production requirements for each device. Programming yields affect the quality and cost of components and PCBs.
While all the options may be attractive in one situation or another, none is perfect. Only after careful internal discussion and consultation with an expert in the programming business should you make a final decision on the best method of integrating its programmable ICs into the production process.
About the Author
Rick Mayes is director of strategic marketing at Data I/O. Before joining the company in 1996, he was the director of marketing for the General Imaging Systems Division at Advanced Technology Laboratories and held various marketing and sales positions at Hewlett-Packard for 16 years. Mr. Mayes has a master’s degree in business administration from the University of Southern California, a master’s degree in electrical engineering from Stanford University, and a B.S. degree in physics and mathematics from New Mexico Tech. Data I/O, 10525 Willows Rd. N.E., Redmond, WA 98073-9746, (206) 881-6444.
Copyright 1997 Nelson Publishing Inc.
May 1997