In a release that addresses multiple trends—IoT device development, customization, small component footprint, low-power devices—Microchip recently showed their MEMS clock generator at electronica 2018.

Microchip Technologies recently released the DSC613, a 3-output low power MEMS clock generator housed in a tiny package that produces up to three separate frequency outputs.

 

 

Wearable devices and Internet of Things (IoT) are two of the most important areas of development in electronics today, and the two criteria they share are the need to conserve both power and board real-estate.

The DSC613 is a micro-electronic-mechanical system (MEMS) oscillator complete within a package as small as 1.6mm x 1.2mm that eliminates the need for three separate quartz oscillator crystals and their associated components. The three available frequency outputs cover a range of possibilities from 2 kHz to 100 MHz.

 

What Is MEMS?

MEMS is an acronym for micro electro mechanical system. They are 3D microstructures and, most importantly, they can be fabricated using the same techniques used to build semiconductors. For oscillators, what is built is, essentially, a tiny tuning fork that, like its full-sized cousin, vibrates at a known, predetermined frequency.

 

The Anatomy of Innovation

The heart of the DSC613 is a MEMS resonator and two-phase lock loops (PLLs).

This innovation can reduce the board space required for timing circuitry by approximately 80%, with a corresponding reduction in overall system weight. Due to the miniscule current requirements of the MEMS resonator and the two PLLs, power requirements are a scant 1 µA standby in standby current, and an economical 5.2 mA in active mode.

 

Block diagram for the DSC613. Image from Microchip Technology

 

Customization

One of the most interesting things about the device is its customizable nature. Microchip’s ClockWorks Configurator must be used to choose the necessary options, create the final part number, data sheet, and order samples.

The DSC613 allows customers to adjust the output frequency and control pin function has a wide operational voltage range of 1.71V to 3.63V, and up to 100MHz operation.

Aside from the three output frequencies, among the options that can be chosen are the temperature range, which can be as wide as  -40°C to 125°C, the package size, what the control input of pin 1 will affect, and even frequency stability, which can be as tight as +/-20ppm. 

 

Pinout for the DSC613. Image from Microchip Technology

 

 

EMI issues become more of a factor than ever in for engineers who design microminature devices. For that reason, the DSC613 can provide spread-spectrum outputs to make EMI problems less of an issue.

 

Environmental Factors

  • The DSC613 is lead-free and RoHS compliant
  • AEC-Q100 automotive stress test qualification for ICs is available
  • Very Fine Pitch Land Grid Array (VFLGA) packaging
  • Shock: Qualified to MIL-STD-883E Method 2002.3, Test Condition G (30,000g)
  • Vibration: Qualified to MIL-STD-883E Method 2007.2, Test Condition C (70g)

 

Options Available for MEMS-Based Timing

MEMS oscillators are difficult to manufacture, and a number of players have dropped out. But, other entrants remain, with rumors of new combatants getting ready to enter the fray. Among those presently available are:

SiTime introduced what was perhaps the first MEMS-based oscillator in 2006, and is said to still have the widest market penetration of any manufacturer. If a 32 kHz oscillator is what you need, SiTime has devices available that draw less than 1 μA and are contained within a footprint 1.5 x 0.8 mm.

muRata manufactures an even small 32 kHz MEMS oscillator, sized at only 0.9 x 0.6 mm. Stability is rated at 160ppm over an operating temperature of -30 to 85°C.

The trick, as always, is to know what you need and to be guilty of neither over-specifying nor under-specifying.

 

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