UM0376
Bill of materials and assembly instructions
11/17
5
Bill of materials and assembly instructions
Table 6
to
Table 15
show the bill of materials, while sections
Section 5.1
to
Section 5.3
provide additional information on assembly.
5.1
Assembly information for analog MEMS
1.
When U10 LD2980CMxx is not assembled use R100 instead. For low voltage MEMS
use a voltage regulator. The maximum supply current is around 1.5 mA per device.
2.
Operational amplifiers are optional.
a)
If they are not necessary, use resistors R80, R81, R82, R83 instead.
b)
If they are required, use operational amplifiers with the following resistor
configuration.
R80, R81, R82, R83 - not assembled
R84, R86, R88, R90 - not assembled
R85, R87, R89, R91 - assembled with 0R.
c)
To alter the gain of the operational amplifiers, use following resistor configuration.
R80, R81, R82, R83 - not assembled
The gain is determined by configuration of R84, R86, R88, R90 and R85, R87,
R89, R91.
d)
In all cases it is recommended to have assembled filtering capacitors C84, C85,
C86, C87. Default is 10 nF, but this can be changed according to the required
filtering features.
3.
Only ONE analog MEMS can be assembled. MEMS analog output pins are shared.
5.2
Assembly information for digital MEMS
1.
When U11 LD2980CMxx is not assembled, use R110 instead. For low voltage MEMS
use a voltage regulator. Maximum supply current is around 1.5 mA per device.
2. Both
I
2
C and SPI are wired.
a)
The unused interface must be selected as floating input or third state.
b)
When using I
2
C, it is recommended to have assembled resistors R01 and R02
which are 4.7 k
Ω
pull-ups.
c)
When using SPI, each device has its own chip select.
3.
The board is designed to have one MEMS assembled on the board although I
2
C and
SPI allows more devices to be used simultaneously. Care should be taken, however
with the RDY/INT pins, as they are shared.
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