Breathing life into obsolete medical device designs

Rochester Electronics’ technical sales manager EMEA, Ken Greenwood, provides a step-by-step guide to managing obsolescence in medical environments.

Biomedical devices are categorized in terms of risk to the patient. Class I devices with low/moderate risk to health; Class II intermediate risk equipment such as Ultra/CT scanners; and Class III/IV devices critical to sustaining life such as dialysis equipment and pacemakers.

As the risk to patients rises, so do the certification costs. Original designs need to be maintained ‘as-is’ for as long as possible. Semiconductor obsolescence presents a serious challenge to the support of biomedical products with long in-service lives and committed maintenance periods.
It is not uncommon for large medical systems to have a concept-to-end-of-life lifecycle of 20 years, including in-service support. By contrast, semiconductor lifecycles continue to shorten especially those of the key processor/FPGA/memory components. It is inevitable that a supply gap of some kind will need to be bridged.

Component obsolescence might be undesirable, but it is generally manageable, at a cost. Typically, end-users commit to a last-time-buy of finished components and the safe long-term storage of the semiconductors—often through a third party because the storage and handling of ICs require special conditions. While this solution ties up cash in long-term component and storage costs, at least precious design and qualification resources are spared. Where future demand exactly matches last-time-buy supply, this is a perfectly adequate solution.
However, as the pandemic took hold, there was a sudden and unpredicted demand for ventilators. Component stocks at the main-line distributors were quickly consumed, and when the semiconductor suppliers themselves were unable to increase capacity, a critical supply gap soon developed.

During this time, approving alternative IC sources, or a full product redesign was not possible given the re-qualification timescales. This is especially true where component obsolescence also impacted software performance.

To bridge the supply chain gap, ventilator manufacturers looked to breathe life into discontinued systems to fulfill this critical need. By using previously approved ICs, such as older die iterations, or by resurrecting older system designs, production was able to continue.

Authorized distributors, such as Rochester Electronics, are the trusted source for discontinued semiconductors after end-of-life. Stock remains fully authorized, stored under AS6496 conditions, providing a risk-free source of supply.

Additionally, partnering with a licensed semiconductor manufacturer, such as Rochester Electronics, can mitigate the risks of component end-of-life. A licensed manufacturer can produce devices no longer supplied by the OCM. When a component is discontinued, the remaining tested wafer and die, the assembly processes, and the original test IP, are transferred to the licensed manufacturer by the OCM. This means that previously discontinued components are still available newly manufactured, and 100 per cent in compliance with the original specifications. No additional qualification is required or software changes.

It is essential for companies in the medical sector to:

• Insist on the maximum number of cross-references from the design phase onwards

• Plan component purchases further in advance

• Consider carrying more inventory of critical semiconductors

• Monitor lead-times and component lifecycles regularly

• Understand supply risks and prepare dual/multi-sourcing strategies to cover all eventualities

• Partner with an authorized distributor and/or licensed manufacturer to help manage and maintain consistent longevity of supply