TECHNICAL NOTE
Safran Colibrys SA
30N.EVBA V2.10.16
Av. des Sciences 13 – 1400 Yverdon-les-Bains - Switzerland
T +41 58 100 5000
www.safran-colibrys.com
page 5
F +41 58 100 5001
2.4
Electrical Schema
The corresponding detailed electrical schema is given below.
Figure 5: EVBA Electronic circuit
2.5
Power Supply
The EVBA power supply is set for +5.0V
DC
(pin8 of J1) and the 0V
DC
must be connected to all VSS pins of J1 (pin
6, pin 9, pin10).
The VS1000 series accelerometers require a +3.30VDC power supply named Vdd. The sensor outputs are
ratiometric to that Vdd voltage level. This could directly impact the accelerometer bias, scale factor, noise or
thermal performance. Therefore, a low-noise, high-stability and low-thermal drift Vdd power supply has been
implemented on the board using an Ultra-Low-Noise, High-Accuracy 3.3V Voltage Reference type ADR4533.
The Sensor Vdd line (+3.30V
DC
) is also connected to PIN 2 of the J1 and can be then used as an output signal
(VDD_S) in order to compensate any variation on the power supply voltage that may impact the accelerometer
signal (ratiometric output).
The voltage Vmid sets to a level of 0.5 x Vdd and is a voltage required by the ASIC of the sensor. For a normal
operation of the sensor this line should be left open. Checking the level shall be only reserved and limited for
debug purposes. Any impedance connected to that line could directly impact the stability, bias, scale factor and
noise figure of the VS1000 series sensors.
