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FAQ High performance MEMS Gyros

GENERAL

What is the status of GYPRO® products regarding Dual-use regulations?

The main legal basis for controls on dual-use goods is the European Union Dual-Use Regulation, also known as Council Regulation (EC) No 428/2009 and associated legal amendments. This legislation is directly applicable in all European Union countries, including France. As such, GYPRO® products are not dual-use products.

Where are GYPRO® products manufactured?

GYPRO® products are manufactured and tested in France, Europe.

Do you provide a Certificate of Compliance for your products?

Each sensor is serialized and delivered with a Certificate of Compliance indicating the following test results :

  • Scale factor nonlinearity at room temperature
  • Scale factor variation over temperature
  • Bias variation over temperature
  • RMS noise [1-100Hz] at room temperature.

Is there an analog output on GYPRO® products?

No, our Gyro is fully digital with a 24-bit SPI output.

What is the MTBF of GYPRO® products?

The reliability of GYPRO® products have been assessed by High Temperature Operating Life Test (HTOL) and High Temperature Storage Life Test (HTSL).
The MTBF for operation at 85°C is 270 000 hours (≈ 30 years).
The MTBF for storage at 100°C is 1,700,000 hours (≈ 200 years).
Additional information can be provided upon request.

Are GYPRO® products sensitive to magnetic fields?

GYPRO® products are silicon-MEMS gyros and as such are not affected by magnetic fields.


INPUT RANGE

Is it possible to adjust the measurement range of the sensor?

For all GYPRO® product, the calibration is performed over ±300 °/s. Nevertheless, as the sensor is using a closed-loop architecture, the excellent linearity of the sensor is maintained over the whole range, even for a lower range or higher range level. If you want to optimize the sensor for a specific measurement range, it is possible to perform a new calibration and store the coefficients inside the IC according to the datasheet.

What is the maximum range of GYPRO® product?

Even if the sensor is specified over a range of ±300°/s, GYPRO® are capable of measuring above this value:
For GYPRO2300 and GYPRO2300LD, the digital output is clamped to ±600°/s
For GYPRO3300, the digital output is clamped to ±838°/s

What is the resolution of GYPRO® products?

Thanks to the 24 digital output, the scale factor is fixed to 10,000 LSB/°/s during manufacturing, corresponding to a resolution of 10-4°/s/LSB, i.e. 0,36 °/h/LSB.


FILTERING / BANDWIDTH / DATA RATE / LATENCY

What are the typical latency of GYPRO® products?

Typical latency is given in respective product datasheet, down to 1ms on the GYPRO3300, ideal for stabilization requirements.

Are the bandwidth and the data rate selectable on GYPRO® products?

No, the bandwidth and the data rate of GYPRO products are fixed during manufacturing and cannot be changed by the customer. However specific needs can be addressed upon request.

Is the data rate exactly 200Hz for GYPRO2300, 1600Hz for GYPRO2300LD and 1800Hz for GYPRO3300?

As the ASIC is self-clocked on the drive frequency of the MEMS resonator, the data rate can vary a bit from one device to another due to the dispersion in the MEMS manufacturing process.

For maximum and minimum values, please refer to the corresponding product datasheet.

What are the different stages of the filtering chain?

On GYPRO2300, the filtering applied on the over sampled sigma delta modulator output is composed of 3 sections :

  • A CIC filter to decimate the input.
  • A Half bandwidth and a drop correction filter to down sample by a factor of two

On GYPRO2300LD and GYPRO3300, only the CIC filter to decimate the output is used. The half bandwidth filter and the drop correction filter are bypassed to reduce the latency of the sensor.


INTEGRATION ON PRINTED CIRCUIT BOARD (PCB)

GREF capacitor

What is the GREF pin voltage?

The typical voltage value for GREF pin is 4,4V.

What is the recommended rate voltage for GREF capacitor?

For reliability reasons, we recommend to use at least a rate voltage of 10V for the GREF capacitor

What is your recommendation about the kind of capacitor?

We recommend to use a tantalum capacitor.

What happens if we don’t connect the GREF capacitance?

GREF is the reference voltage used for excitation and actuation of the proof masses. If the filtering capacitance is not connected, the noise will increase considerably.


PLL filter

What is the PLLF pin voltage?

The PLL pin voltage range is between 0.15V and 1.65V. This value varies with temperature.

5,6µF is not a standard value for a capacitor and I have some difficulties to source it. Is it possible to use a 4,7µF capacitor instead of 5.6µF capacitor?

Yes it is possible to use a 4,7µF capacitor even if the optimized value is 5,6µF. In general reducing the capacitor size will increase the PLL Bandwidth which increases the noise contribution, but the difference between these two values is limited.

Will the sensor performance be affected by the PCB mounting?

During factory calibration, each sensor is already temperature-compensated over the operating temperature range. Soldering to the PCB can lead to minor errors in the bias and scale factor over the operating temperature range.

To achieve optimal performances over temperature, it is recommended to perform a new compensation at the system level.

GYPRO products run from a 5V supply, but I would like to interface with a 3.3V microcontroller. How I can proceed?

All the GYPRO digital pins work on a 5V voltage level, so you need to add a level shifter. For example, the level shifter used on Tronics Evaluation board is a TXB0108PWR.

Do you have a 2D or 3D model for GYPRO2300 and GYPRO3300?

A 3D model (.step) is available on our web site (link)
2D model (.dxf) are also available upon request.


PRODUCT COMPATIBILITY

What is the difference between GYPRO2300, GYPRO2300LD and GYPRO3300?

The only difference between GYPRO2300 and GYPRO2300LD is the configuration of the IC. Some filtering stages have been bypassed on the GYPRO2300LD in order to reduce the latency down to 2ms.

The GYPRO3300 has been designed to improve the sensor behavior under strong vibration condition.

Is it possible to switch a GYPRO2300 into a GYPRO2300LD?

No, the IC configuration has been programmed on the OTP (One Time Programmable) memory of the sensor and it not possible to change it anymore.

I have developed a system with GYPRO2300 and I want to evaluate the GYPRO3300. Is GYPRO3300 compatible with GYPRO2300 hardware and software?

The answer is yes.
The hardware is compatible, but there are two changes on the pinout, as described below:

CLCK400K is not available on GYPRO3300, but there is no issue if you have connected this pin in your system.
DRY is a digital output which generates a pulse when a new data is available. There is no issue if you haven’t connected this pin in your system.

In term of software, the basic SPI command to read the angular rate data and temperature data are the same. Nevertheless, there are some differences regarding advanced SPI commands (please refer to the product datasheets).