IDG-650 INVENSENSE, IDG-650 Datasheet - Page 7

• Manufacturer Part Number: IDG-650
• Description: GYRO, DUAL (X+Y) AXIS, +/-2000 DEG/S
• Manufacturer: INVENSENSE

Specifications of IDG-650

• No. Of Axes: 2
• Sensor Case Style: QFN
• No. Of Pins: 28
• Supply Voltage Range: 2.7V To 3.3V
• Operating Temperature Range: -20°C To +85°C
• Sensitivity Per Axis: 0.5mV / ° / S
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

6.4
The scale factor of the gyroscope depends on the amplitude of the mechanical motion and the trim setting of
the internal programmable gain stages. The oscillation circuit precisely controls the amplitude to maintain
constant sensitivity over the temperature range. The capacitors (0.22µF ±10%) connected to Pin 6 (XAGC)
and Pin 15 (YAGC) are compensation capacitors for the amplitude control loops.
6.5
Rotating the sensor about the X- or Y-axis results in a Coriolis force on the corresponding X- or Y-rate
sensor. The Coriolis force causes the mechanical structure to vibrate in-plane. The resulting vibration is
detected by measuring the capacitance change between the mechanical structure and fixed electrodes. This
signal is converted to a voltage waveform by means of low-noise charge integrating amplifier and
amplification stages.
6.6
The output of the Coriolis sense is an amplitude modulated waveform. The amplitude corresponds to the
rotation rate, and the carrier frequency is the mechanical drive frequency. The synchronous demodulator
converts the Coriolis sense waveform to the low-frequency, angular rate signal.
6.7
After the demodulation stage, there is a low-pass filter. This filter attenuates noise and high frequency
artifacts before final amplification.
6.8
The Auto Zero function is used to reduce DC offset caused by bias drift. The use of this function will vary by
application requirement. Pin 24 (AZ) is used to set the Auto Zero function, resetting the bias to approximately
VREF.
6.9
A built-in Proportional-To-Absolute-Temperature (PTAT) sensor provides temperature information on Pin 23.
6.10 Charge Pump
The on-chip charge pump generates the voltage required to oscillate the mechanical structure.
6.11 Memory Trim
The on-chip memory is used to select the gyro‟s sensitivity, calibrate the sensitivity, null DC offsets and
select the low-pass filter option
6.12 Scale Factor
The Rate-Out of the gyros is not ratiometric to the supply voltage. The scale factor is calibrated at the factory
and is nominally independent of supply voltage.
6.13 Reference Voltage
The gyro includes a bandgap reference circuit. The output voltage is typically 1.35V and is nominally
independent of temperature. The zero-rate signal is nominally equal to the reference value.
6.14 Analog Outputs
The IDG-650 gyro has two X-outputs (X-OUT and X4.5OUT), and two Y-outputs (Y-OUT and Y4.5OUT), with
scale factors and full-scale sensitivities that vary by a factor of 4.5, as detailed in Section 8.2.7.
Having two sensitivities and two full-scale ranges per axis allows the end user to have one output that can be
used for faster motions (over a full scale range of ±2000º/sec), and a second output that can be used for
slower motions (over a full scale range of ±440º/sec). Thus a lower-resolution analog-to-digital converter
(ADC) may be used to digitize the motion, with the gain of 4.5 in the X4.5OUT and Y4.5OUT outputs
effectively giving the user an additional two-plus bit of resolution.
Amplitude Control
Coriolis Sense
Demodulator
Low-Pass Filter
Auto Zero
Temperature Sensor
IDG-650 Dual-Axis Gyroscope
Product Specification
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PS-IDG-0650B-00-05
Release Date: 05/20/10