LPS33HW - XREA(エクスリア)axisdevice.s601.xrea.com/uploader/gif/Water proof design...
Transcript of LPS33HW - XREA(エクスリア)axisdevice.s601.xrea.com/uploader/gif/Water proof design...
LPS33HWMechanical Design reference & Measurement results
Sept 2017
MEMS Sensor Division
LPS33HW Package Detail 2
Analog, MEMS and Sensors Product Group 26 September 2017
LPS33HW Package Details
• 3.3 x 3.3 x 2.9 mm (max) CCLGA-10L package
• Metal Lid with diameter 1.6mm vent hole size
CCLGA-10L,
3.3 x 3.3 x 2.9mmceramic
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Analog, MEMS and Sensors Product Group 26 September 2017
LPS33HW Mechanical dimension
Water Proof Design Reference 4
Analog, MEMS and Sensors Product Group 26 September 2017
Simulated to to check enough contact pressure between O-ring and two contacts (metal lid
& plastic case) for hydrostatic pressure of 10 bar.
PCB
O-ring
LPS33HW with O-ring
2.98mm ± 0.03mm
O-ring
• Commercial O-ring
• 1.8mm inner diameter
• 1.0mm thickness
Reference of Water proof sealing
We recommend that O-Ring outer diameter (inner diameter + 2 x thickness) has overthan 3.15mm considering 2.98mm of inlet diameter. O-Ring diameter need to be widerthan inlet of IC.
Set-Up of Sealing STUDY 5
Comsol Model set up for contact pair FEM analysis ( cross section)
contact pairs
P=1[MPa] hydrostatic
press
0,95 mm
0,750 mm
1,7 mm
FR4
SS
Ste
el
FIXED boundary
O-Ring : NBR 7090
6Simulation Result
1.45Mpa contact pressure
Simulation Result with LPS33HW after assembly
7Summary
In simulation, estimated surface contact pressure between O-Ring and two contact sides
(Lid of LPS33HW & Plastic CASE) is 1.45Mpa.
Sealing against 10bar water is guaranteed in this case because:
Fluidic_hydrostatic_pressure < Contact_pressure (i.e 10bar (1Mpa) ≤ 1.45Mpa)
O-ring life time is preserved if groove depth is 70% of O-ring Section diameter
Contact pressure : 1.45Mpa
Water Pressure 1Mpa (10bar)
Overpressure Stress Test
Analog, MEMS and Sensors Product Group 26 September 2017
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10 bar short time, 10sec and 60sec 9
Test condition : 1.5 / 3 / 5 / 10 bar over pressure for 10sec & 60sec
Recovery time analysis for becoming less than 0.5hPa
Less overpressure stress time makes the faster recovery time & result summary in below
Recovery time 0.7min @ 5bar for 10sec
Recovery time 1.2min @ 10bar for 10 sec Air pressure was used
1010 bar short time, 2 sec
10min
Assuming swimming use case: Short and repeated over-pressure
Air pressure was used
Water removal
and drying while
Device on
Zoom in
Takes several to come back to baseline.
No physical & electrical damage 10 bar over-pressure for 24hr
10 bar long time, 24hrs
Sensing part was covered by water,
and it was pressed through air.
Chemical testChlorine, Bromine and Salt Water
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User Condition TestChlorine, Bromine and Salt Water
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LPS33HW Test trial on real user Test @ Hot Chlorine or Bromine for case of swimming in the pool with each disinfectant.
Test @ Salt Water for case of swimming in the sea.
Test under each bottle of Chlorine , Bromine
and Salt water
Test strip using to confirm test condition.
Aqua check strip & measurement scale
Chlorine : 4ppm
Bromine : 5ppm
Ph : 8~8.2
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Test procedure of 1 cycle 10pcs samples in each water solution with 30’C (+/-1’C) for Chlorine & Bromine , 21’C(+/-1’C) for salt
water solution.
Leave this condition for 6hr
Take out the samples from each water and put in climatic Chamber @ 60’C/60%rH for 18hr
Test Points every 6 cycle (last round after 10 cycles) Electrical check of pressure reading.
Microscope inspection for verifying any possible damage at the end of last round.
User Condition Test Chlorine, Bromine and Salt Water
Summary - Test Result
• 10 device of LPS33HW were tested under Chlorine, Bromine and Salt
water solution up to 34 cycles (34days, 1cycle = 24hr)
• No physical damage confirmed by Microscope inspection & No
electrical accuracy drift problem after test with each disinfectant & salt
water condition .
• The result means No damage & electrical problem are predicted
under condition with swimming pool and sea as real user case.