CMA3000-D01 DEMO VTI Technologies, CMA3000-D01 DEMO Datasheet - Page 12

• Manufacturer Part Number: CMA3000-D01 DEMO
• Description: KIT DEMO ACCELEROMTR CMA3000-D01
• Manufacturer: VTI Technologies

Specifications of CMA3000-D01 DEMO

• Mfg Application Notes: CMA3000 Assembly Instructions C-Code Examples for CMA3000 Accelerometer Sub-1 uA Current Consumption with CMA3000
• Sensor Type: Accelerometer, 3 Axis
• Sensing Range: ±2g, 8g
• Interface: I²C, SPI
• Sensitivity: 56, 14 count/g
• Voltage - Supply: 5 VDC, USB Powered
• Embedded: No
• Utilized Ic / Part: CMA3000-D01
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 551-1066

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VTI Technologies Oy
www.vti.fi
CMA3000 current consumption measurement with DEMO KIT
The current consumption of the CMA3000 sensor can be calculated by measuring the voltage drop
over the resistor R34 (470 Ω, 1% tolerance). Voltage drop can be measured from test points TP5
and TP6, see DEMO KIT USB interface board circuit diagram in Figure 16 (PCB design
VTI 29393 rev B0).
The offset current consumption of the DEMO KIT hardware depends on used serial communication
(SPI vs. I
in Table 3 below.
Table 3. Offset current consumption of the CMA3000 DEMO KIT HW.
The offset current consumption can also be measured by measuring the voltage drop over the
resistor R34 (TP5 and TP6, see Figure 16) when CMA3000 PWB is not connected to USB
interface board.
SCA3000 current consumption can be calculated
where V
measured offset current consumption (from TP5 to TP6, see Figure 16), alternatively the values
from Table 3 can be used. Idd is the CMA3000 current consumption in [A].
The difference in offset current consumption is due the pull up resistor in SCK/SCL line (R2 in
Figure 15). When using SPI-bus, the MCU software drives the SCK/SCL line low when there is no
communication, which results in increase in DEMO KIT offset current consumption (current through
resistor R2 in Figure 15 from DVDD to GND). When I
line when there is no communication.
Idd
Serial interface
Figure 13. SCA3000 demo output during data logging.
=
SPI
I
⎛
⎜ ⎜
⎝
2
V
C
drop
2
drop
C). The offset current consumption according to serial communication type is presented
470
is the measured voltage drop in [V] (from TP5 to TP6, see Figure 16), V
−
V
Ω
offset
Offset current consumption
~950 µA (V
~200 µA (V
⎞
⎟ ⎟
⎠
,
offset
offset
= 444 mV)
Doc.Nr. 8288400.02
= 94 mV)
2
C is used, the MCU releases the SCK/SCL
SCA3000 DEMO KIT
(1)
User Manual
offset
Rev.0.2
is the
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