BMA020 Bosch Sensortec, BMA020 Datasheet - Page 44

• Manufacturer Part Number: BMA020
• Description: 3-AXIS ACCELEROMETER DIGITAL I/F
• Manufacturer: Bosch Sensortec

Specifications of BMA020

• Axis: X, Y, Z
• Acceleration Range: ± 2g, 4g, 8g
• Sensitivity: 256LSB/g, 128LSB/g, 64LSB/g
• Voltage - Supply: 2 V ~ 3.6 V
• Output Type: Digital
• Bandwidth: 3kHz
• Interface: I²C, SPI
• Mounting Type: Surface Mount
• Package / Case: 12-LGA
• For Use With: 828-1014 - BMA020 TRIBOX DEMO BOARD W/USB828-1008 - BMA020 DAUGHTERCARD FOR DEV KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 828-1000-2

output can be generated and trigger the system master. The wake-up mode is used for ultra-low
power applications where inertial factors can be an indicator to change the activity mode of the
system.
The following table shows values calculated for the average current consumption during the
wake-up mode of the BMA020. The power consumption in wake-up mode is dependent on the
duration of the interrupt algorithm (number of data acquisitions) and the bandwidth (for more
details on setting of the bandwidth please refer to chapter 3.1.3).
Table 13: Average current consumption in self wake-up mode using high-g or low-g interrupt
Pause [ms]
Durations of the pause values can vary for about ±30% due to the accuracy of the ultra-low-
power oscillator implemented within the sensor.
For estimating the typical current consumption in wake-up mode the following formula can be
applied:
i_self_wake_up = (i_DD · t_active + i_DDsbm · wake-up-pause) / (t_active + wake-up-pause)
With the approximation:
With the following parameters:
Rev. 1.2
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Note: Specifications within this document are subject to change without notice.
2,560
360
20
80
t_active = 1ms + 0.333ms · (4
i_DD
i_DDsm
wake_up_pause
n
Bandwidth
(@ 1,500Hz)
16.3
5.1
1.9
1.1
Current consumption during BMA020 wake-up mode [µA]
(depending on bandwidth, calculated using typical values)
Current in normal mode
Current in sleep mode
Setting of wake-up pause
number of data points in any-motion logic
(n=0 for high-g threshold and low-g threshold interrupt,
n=3 for any-motion logic)
Setting of bandwidth (750-25 Hz),
for 1500Hz t_active = 1ms + 0.333ms · (1500/bandwidth) · n
Digital, triaxial acceleration sensor
(@ 750Hz)
21,8
6.6
2.3
1.2
⋅
750 / bandwidth) + 0.333ms · (1500 / bandwidth) · n
Data sheet
BMA020
Page 44
(@375Hz)
31.8
9.7
3.0
1.3
(@190Hz)
48.4
15.4
4.4
1.5
(@100Hz)
71.6
25.0
6.9
1.9
(@50Hz)
Bosch Sensortec
102.9
42.3
12.0
2.6
30 May 2008
(@25Hz)
134.7
68.4
21.3
4.1