A111 Pulsed Coherent Radar (PCR)
Datasheet, v1.8
Page 25 of 34
2019-06-12
© 2019 Copyright by Acconeer
8.4 Power supply
The A111 sensor has got three power supplies where the VIO_3 power supply is sensitive to power
supply ripple. Power supply ripple on VIO_3 may degrade performance since VIO_3 supplies the
internal clock generation blocks. Table 8.4 provides the required power supply ripple specification for
VIO_3.
Frequency (Hz)
Min.
Typ.
Max.
Unit
10 000
18.7
mV
pp
100 000
2.6
mV
pp
1 000 000
0.26
mV
pp
3 000 000
0.09
mV
pp
10 000 000
0.23
mV
pp
100 000 000
3.0
mV
pp
Table 8.4: Required power supply ripple specification for VIO_3
Low-cost LC filter solution
Acconeer provides recommended low-cost LC filter solution, the recommended filter is displayed in
figure 8.2. The values of the component demonstrate an example filter design, exact values depend on
switching frequency and ripple amplitude of the supply regulator. However, be aware of LC filter
peaking at the series resonance frequency 1/(2π*sqrt(LC)). A small resistor, 250 m
Ω
in the example
filter, can be inserted to lower the Q factor of the filter. In certain applications, where disturbances at
the series resonance frequency is present, the filter may not be an optimal solution and an external
LDO such as TPS7A8801 or equal is recommended to use instead of the low-cost LC filter.
VIO_3a,b
22uF
2.2uH
250 m
Ω
Supply
100nF
Figure 8.2: Low cost LC supply filter
