Specifying MEMS Oscillators
Micro Electro Mechanical Systems or MEMS as it is commonly known is the latest technology to be used in the Frequency Products market as an alternative to quartz based devices.
MEMS devices use a "silicon-beam" rather than quartz as the frequency control element which provides advantages such as small package size and good environmental performance for shock and vibration.
IQD’s series of MEMS devices use an internal MEMS resonator and a factory programmable oscillator circuit to provide the output frequency required by the customer.
Our range of devices include clock oscillators (IQMS series) and voltage controlled devices (IQMV series) in 4 package sizes and 4 supply voltage options.
The IQMS-500 and IQMV-600 series of oscillators provide enhanced performance including low jitter, low frequency stability and for the IQMV series, a choice of pullability options.
The electrical parameters are given on the specification to facilitate the correct circuit design. Further guidance can be found in the Application Notes chapter of this book. Our Application Support team can also provide assistance if required; please contact one of our sales offices for this support.
The limits given in the following specifications are indicative of the standard MEMS oscillator design, in the event that a specification is needed which is outside the standard MEMS oscillator designs offered please contact our Sales team.
Fast Make Capability
Due to the fact that MEMS oscillators are programmable, we are able to offer a fast make capability for this range of devices.
A typical MEMS specification reads like this:
CMOS ±50ppm –20 to 70C 3.3V TS
The data in the example above is translated in the following order
- Output Compatiblity
- Frequency Stability
- Operating Temperature Range
- Supply Voltage
- Tri-State/Standby Option
Frequency is normally specified in kilohertz (kHz) up to 999.999kHz and in megahertz (MHz) from 1.0MHz. All our computer-generated transaction documents follow this standard convention automatically.
The MEMS oscillator frequency should be specified to seven significant figures. If seven significant figures are not used, we assume that any figure that might follow those given may be taken as zero. Thus a frequency given as 16.6MHz will be taken as 16.60, not 16.6666.
The model number incorporates information which describes supply voltage, output compatibility and holder style.
As defined by the chosen model MEMS devices are available with either standard CMOS, LVDS or LVPECL outputs.
The frequency stability of a MEMS oscillator includes the initial adjustment tolerance at room temperature and the tolerance over operating temperature range. This value is specified as ‘parts per million’ (ppm) and is available in the ranges as shown below.
Operating Temperature Ranges
0 to 70°C
–20 to 70°C
–40 to 85°C
Although in general MEMS oscillators will continue to operate outside their normal temperature range with a degradation in frequency stability, damage can result if the temperatures reached are excessive.
Frequency Pullability (IQMV-600)
As standard the centre trim voltage is +0.875V. The pullability is specified as the change in frequency when the trim voltage is varied from 0V to +1.85V. This value is specified in ‘parts per million’ (ppm). Please see individual data sheets for further details.
The IQMS series of MEMS has the option of specifying either Tri-State (code TS) or Standby (code ST) as a function of the output signal. When in tri-state mode the output goes to the high impedance state while in standby mode the internal oscillator stops and the output signal goes to a low level. So TS will give fast start up time while ST will give low standby power consumption.
Additional Text Code
If the product is non-standard, the letter ‘T’ and/or ‘E’ will appear at the end of the product specification. This refers to additional text on the quotation/sales order to identify the non-standard requirements.
Tape and Reel packaging is available as an option on many of the products outlined in this chapter.
Unless individual data sheets state Tape and Reel packaging, items will be Bulk packed. Please note: only complete reels are sold.
Bulk = Bulk packed
Reel = Tape and Reel packed
Dimensions on the MEMS oscillators drawings are shown only as a guide. Precise dimensions of the MEMS oscillators holders are available upon request. All dimensions are shown in mm and are nominal unless otherwise stated.
See individual data sheets