In low-power electronics, timing sources are an implicit driver of battery life, reliability, and performance. For decades, quartz crystals have been the standard timing element in electronics until the advent of silicon-based micromachined electromechanical system (MEMS) oscillators.
The choice of MEMS oscillators is one of the most influential steps in designing applications from wearable devices and IoT sensors to industrial and high-speed digital systems. This crystal is etched on a silicon wafer and vibrates at an accurate frequency to provide a stable digital timing signal.
Quartz crystals have been used since the 1930s and rely on the piezoelectric property of the applied voltage to vibrate at an accurate frequency. The natural stability of quartz crystals ensures long and reliable timing of devices such as microcontrollers and radios.
However, quartz crystals are relatively brittle and operate at a particular frequency, causing problems during design iterations and frequency customization. In addition, quartz crystals stabilize only a few milliseconds after being energized, making them unsuitable for low-power devices with frequent sleep cycles.
Electronic alternatives, such as RC and LC oscillators, can generate clock signals from electronic components, but may drift frequency due to temperature, voltage, or aging.
MEMS oscillators combine the mechanical stability of quartz with miniaturization, impact resistance, and configurability of silicon. Therefore, this oscillator is ideal for applications that require low power consumption, rugged or limited space. The oscillator wakes up at microsecond speeds, maintains stability and low power consumption during temperature changes, resulting in longer operating time, smaller batteries, and a more compact, rugged design.
Seismic, programmable options
Abracan offers a range of timing and frequency control devices, including the AMMLP series MEMS oscillator, for high precision frequency control in an ultracompact, low power package (Figure 1). Compared with traditional quartz, AMMLP devices are characterized by impact resistance, ultra-small size and programmability, etc., completely meeting the design frequency and packaging requirements of engineers.
Figure 1: Abracan's AMMLP series MEMS oscillators feature industry standard packaging and wide frequency selection range. Image source: Abracan)
From a new generation of fitness trackers to autonomous UAVs, the AMMLP Oscillator provides precise, low-power timing for modern applications. AMMLP devices range from 2.3 MHz to 170 MHz and are available in a wide range of accuracy, low power consumption and flexibility. These devices support four supply voltages: 1.8 V, 2.5 V, 3.3 V or 2.25 V to 3.6 V continuous.
From a power consumption point of view, the AMMLP Oscillator is built for energy conservation, typically with a current consumption of about 6.5 mA, and many models also include a Standby or Output Enable mode to enter a dormant state when the device is energy efficient. With industry standard package sizes of 2.0 x 1.6 mm, 2.5 x 2.0 mm, 3.2 x 2.5 mm, 5.0 x 3.2 mm and 7.0 x 5.0 mm, the oscillator allows easy embedded integration even in the most compact design.
Stability of frequency
The Abracan device is factory programmable for virtually any frequency in its range. A wide temperature range of ± 20 ppm to ± 50 ppm can be selected and such stringent frequency stability ensures timing consistency for portable industrial or consumer applications.
AMMLPAALJS-24.000T is a 2.0 x 1.6 mm MEMS oscillator that saves PCB space while providing high accuracy, low power 24 MHz IF. This oscillator provides stable clock signals for microcontrollers, radio frequency and other digital circuits with a supply voltage of 2.25 V to 3.63 V, a maximum operating current of 7.5 mA and a standby current of only 1.8 µ A, making it ideal for battery-powered devices.
AMMLPDALJS-25.0000T is slightly larger, 2.5 x 2.0 mm and operates at 25 MHz, which is normally used for Ethernet, USB and some wireless radios. The typical standby current of this device is only 1 µ A, and it also has a flexible operating voltage of 2.25 V to 3.63 V, which ensures efficient operation in portable or industrial designs.
MHz AMMLPDDLJS-50.0000T uses 2.5 x 2.0 mm package, 1 µ A stand-by power, supports 1.8 V power supply, and operates up to 7.5 mA. The compact, low power consumption oscillator is ideal for demanding space and energy efficiency.
All three devices have ± 20 ppm frequency stability and CMOS output to simplify application design.