FXLS8471Q
Rev. 3.0 — 13 June 2019
3-Axis, Linear Accelerometer
Product data sheet
1
General description
FXLS8471Q is a small, low-power, 3-axis, linear accelerometer in a
3 mm x 3 mm x 1 mm QFN package. FXLS8471Q has dynamically selectable
acceleration full-scale ranges of ±2
g/±4 g/±8 g
and 14 bits of resolution. Output data
2
rates (ODR) are programmable from 1.563 Hz to 800 Hz. I C and SPI serial digital
interfaces are provided along with several user programmable event detection functions
that can be used to reduce the overall system power consumption by off-loading the host
processor. FXLS8471Q is guaranteed to operate over the extended temperature range of
–40 °C to +105 °C.
2
Features and benefits
•
•
•
•
•
•
1.95 V to 3.6 V VDD supply voltage, 1.62 V to 3.6 V VDDIO voltage
±2
g/±4 g/±8 g
dynamically selectable acceleration full-scale ranges
Output Data Rates (ODR) from 1.563 Hz to 800 Hz
Low noise: typically 99 μg/Hz in low-noise mode @ 200-Hz bandwidth
14-bit ADC resolution: 0.244 mg/LSB in ±2
g
full-scale range
Embedded programmable acceleration event functions
–
Freefall and motion detection
–
Transient detection
–
Vector-Magnitude change detection
–
Pulse and tap detection (single and double)
–
Orientation detection (portrait/landscape)
Programmable automatic ODR change using Auto-Wake and return to Sleep functions
to save power
192-byte FIFO buffer, capable of storing up to 32 samples of X/Y/Z data
2
Supports SPI interface at up to 1 MHz; I C Normal (100 kHz) and Fast modes
(400 kHz)
Integrated self-test function
Integrated temperature sensor with 8-bit output resolution
•
•
•
•
•
3
Typical applications
Automotive convenience and security
•
Tilt sensing, orientation detection, vibration sensing
•
Navigation applications
Industrial IOT
•
Asset tracking
•
Equipment monitoring: vibration analysis, machine health
NXP Semiconductors
3-Axis, Linear Accelerometer
Medical
•
Patient and activity monitors
Consumer devices
•
Wearables
•
Portable electronics
FXLS8471Q
4
Ordering information
Temperature range
–40 °C to +105 °C
Package
Name
Description
Version
VQFN16
plastic, very thin quad flatpack; no leads; 16 terminals; SOT1676-1
0.5 mm pitch; 3 mm x 3 mm x 1 mm body
Table 1. Ordering information
Type number
FXLS8471Q
5
Block Diagram
Figure 1. Block diagram
FXLS8471Q
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© NXP B.V. 2019. All rights reserved.
Product data sheet
Rev. 3.0 — 13 June 2019
2 / 86
NXP Semiconductors
3-Axis, Linear Accelerometer
FXLS8471Q
6
Pinning information
6.1 Pinning
VDD
14
RST
16
1
2
3
4
5
6
7
SDA/MOSI
SA0/MISO
n.c.
8
n.c.
15
pin 1
index area
VDDIO
BYP
Reserved
SCL/SCLK
GND
13
12
Reserved
GND
INT1
SA1/CS_B
INT2
FXLS8471Q
11
10
9
aaa-031461
Transparent top view
Figure 2. Pinning
6.2 Pin description
Table 2. Pin Description
Symbol
VDDIO
BYP
Reserved
SCL/SCLK
GND
SDA/MOSI
SA0/MISO
n.c.
INT2
SA1/CS_B
INT1
GND
Reserved
VDD
N/C
RST
[1]
[2]
[1]
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Description
Interface power supply
Internal regulator output bypass capacitor connection
Test reserved, connect to GND
I C Serial Clock/SPI Clock
Ground
I C Serial Data/SPI Master Out, Slave In
I C address selection bit 0/SPI Master In, Slave Out
Internally not connected
Interrupt 2
I C address selection bit 1 /SPI Chip Select (active low)
Interrupt 1
Ground
Test reserved, connect to GND
Power supply
Internally not connected
Reset input, active high. Connect to GND if unused
2
[2]
2
2
2
The SA0 pin is also used to select the desired serial interface mode during POR and also after a hard/soft reset event. See
Section 10.2.3
for more
information
2
See
Table 4
for I C address options selectable using the SA0 and SA1 pins.
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2019. All rights reserved.
FXLS8471Q
Product data sheet
Rev. 3.0 — 13 June 2019
3 / 86
NXP Semiconductors
3-Axis, Linear Accelerometer
FXLS8471Q
7
Orientation
Figure 3. Product orientation and axis orientation
8
Electrical connections
Device power is supplied through the VDD pin. Power supply decoupling capacitors
(100 nF ceramic plus 4.7 μF bulk) should be placed as close as possible to pin 14 of the
device. The digital interface supply voltage (VDDIO) should be decoupled with a 100 nF
ceramic capacitor placed as close as possible to pin 1 of the device.
The digital control signals SCL, SDA, SA0, SA1 and RST are not tolerant of voltages
exceeding VDDIO + 0.3 V. If VDDIO is removed, these pins will clamp any logic signals
through their internal ESD protection diodes.
The function and timing of the two interrupt pins (INT1 and INT2) are user programmable
2
2
through the I C/SPI interface. The SDA and SCL I C connections are open drain and
therefore require a pullup resistor as shown in the application diagram in
Figure 4.
The INT1 and INT2 pins may also be configured for open-drain operation. If they are
configured for open drain, external pullup resistors are required.
FXLS8471Q
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2019. All rights reserved.
Product data sheet
Rev. 3.0 — 13 June 2019
4 / 86
NXP Semiconductors
3-Axis, Linear Accelerometer
FXLS8471Q
Figure 4. Electrical connection
9
Terminology
9.1 Sensitivity
Sensitivity is represented in mg/LSB; the accelerometer sensitivity changes with the full-
scale range selected by the user. Accelerometer sensitivity is 0.244 mg/LSB in 2
g
mode,
0.488 mg/LSB in 4
g
mode, and 0.976 mg/LSB in 8
g
mode.
9.2 Zero-g offset
Zero-g offset describes the deviation of an actual output signal from the ideal output
signal while the sensor is stationary. A sensor stationary on a horizontal surface will
measure 0
g
in X-axis and 0
g
in Y-axis, whereas the Z-axis will measure 1
g.
A deviation
from an ideal value in this case is called
Zero-g offset.
Offset is, to some extent, a result
of stress on the MEMS sensor. Therefore, the offset can slightly change after mounting
the sensor onto a printed circuit board, or after exposure to extensive mechanical stress.
9.3 Self-test
Self-test can be used to verify the transducer and signal chain functionality without the
need to apply an acceleration stimulus. When the accelerometer self-test is activated, an
electrostatic actuation force is applied to the sensor, simulating a small acceleration. In
this case the sensor X, Y, and Z outputs will exhibit a change in DC levels related to the
selected full-scale range (sensitivity). When self-test is activated, the device output level
is given by the algebraic sum of the signals produced by the acceleration acting on the
sensor and by the electrostatic self-test force.
FXLS8471Q
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2019. All rights reserved.
Product data sheet
Rev. 3.0 — 13 June 2019
5 / 86
