LPR550AL Datasheet, PDF (8/12 Pages) STMicroelectronics – MEMS motion sensor: dual axis pitch and roll ±500°/s analog gyroscope

Application hints
4
Application hints
LPR550AL
Figure 3. LPR550AL electrical connections and external component values
10nF ^C2
10kOhm
470nF
GND GND
Vdd
+Ω _Y
+ Ω_X
R1
C1
Not amplified
filtered output Y
100 nF 10 µF
GND
16
1
14
13
LPR550AL
(Top View)
(TOP VIEW)
DIRECTION OF THE
DETECTABLE
ANGULAR RATES
HP
PD
Not amplified
ST
filtered output X
R2
C2
C1
R1
5
6
GND
Vref
Recomended Optional
Low-pass filter High-pass filter
Typical values:
R1 = 1MOhm
C1 = 4.7 µF
R2 = 33kOhm
C2 = 2.2 nF to 2.2 µF
89
C1
R1
R2
C2
Vref
GND
Power supply decoupling capacitors (100 nF ceramic or polyester + 10 µF Aluminum)
should be placed as near as possible to the device (common design practice).
The LPR550AL allows band limiting the output rate response through the use of an external
low pass filter (suggested) and/or high pass filter (optional) in addition to the embedded low
pass filter (f_t = 140 Hz).
4xOUTX and 4xOUTY are respectively OUTX and OUTY amplified outputs lines, internally
buffered to ensure low output impedance.
If external high pass or low pass filtering is not applied it is mandatory to short-circuit
respectively pad 4 to pad 5 and pad 9 to pad 10 when amplified outputs are used.
When only not_amplified outputs are used (OUTX/Y), it is suggested to set pads 5 and 9 to
fixed reference voltage (GND/Vref).
When high pass filter is applied to not amplified output (OUTx), it is recommended to buffer
the line before entering ADC for performance optimization.
The LPR550AL IC includes a PLL (phase locked loop) circuit to synchronize driving and
sensing interfaces. Capacitors and resistors must be added at the FILTVDD and VCONT
pins (as shown in Figure 3) to implement a low-pass filter.
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Doc ID 15813 Rev 2