Resistance-optimised quartz crystals for energy-efficient medical technology

Battery-powered medical devices must operate reliably over long periods whilst consuming as little energy as possible. Whether portable patient monitors, insulin pumps, pulse oximeters, hearing aids or networked sensors – every microwatt saved extends the operating time and reduces maintenance requirements. In addition to microcontrollers and wireless technology, the crystal oscillator used also has a significant influence on a system’s energy requirements.

An important factor is the equivalent series resistance (ESR) of the quartz resonator. The lower this value, the faster the oscillator reaches its stable operating state. This shortens the settling phase, during which the circuit draws a higher current. Particularly in devices that regularly wake up from sleep mode, this effect adds up over many thousands of operating cycles to result in a noticeable energy saving.

Using LRT (Low ESR Resonator) technology, PETERMANN-TECHNIK develops quartz resonators in which the series resistance has been specifically reduced. The result is resonators with particularly good response characteristics and high stability in practical use.

The quartz resonators used are developed and manufactured in-house. This ensures consistent product characteristics over many years. This long-term consistency is of particular importance in medical technology, as products are often manufactured and approved without change for many years. In addition, every single LRT quartz crystal is fully tested, ensuring that only calibrated components are supplied.

In medical applications, an oscillator that starts up reliably is far more than just a convenience feature. Devices must operate reliably even under difficult conditions – for example, at low battery voltage, with significant temperature fluctuations or due to variations between individual electronic components.

Thanks to their reduced ESR, LRT crystal oscillators have a high oscillation margin. This increases the likelihood of a reliable start-up even in critical circuits where the oscillator amplifier offers only a small margin. This gives developers additional confidence when designing their hardware and enables them to significantly reduce the risk of problems arising during mass production.

Many modern medical devices now communicate wirelessly, for example via Bluetooth® Low Energy or other low-power wireless standards. In addition to reliable start-up, frequency stability therefore also plays an important role.

A precise clock source supports stable wireless connections and can help to prevent transmission retries. This shortens the system’s active transmission time, which further reduces energy consumption whilst simultaneously improving communication quality.

In addition to its core frequency products, PETERMANN-TECHNIK supports developers right from the design stage of new devices. This includes, amongst other things, in-circuit measurements, analysis of the settling time, assessment of the drive level, and optimisation of the load capacity directly within the target circuit.

Another key focus is on the long-term availability of products. Particularly in the medical sector, with its long product life cycles and extensive approval procedures, a clock source that is consistently available makes a significant contribution to investment and planning security.

PETERMANN-TECHNIK GmbH, based in Landsberg am Lech, has been developing and marketing high-quality frequency products for industrial and medical applications since 1996. The company supports its customers from the selection of suitable quartz crystals through the design-in phase right through to series production, placing particular emphasis on product quality, long-term availability and technical advice.