A111 Pulsed Coherent Radar (PCR)

Datasheet, v2.8

© 2022 Copyright by Acconeer

2022-06-22

Page 24 of 35

9.2 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 9.2 provides the required power supply ripple specification for

VIO_3.

Frequency (Hz)

Min.

Typ.

Max.

Unit

10 000

18.7

mVpp

100 000

2.6

mVpp

1 000 000

0.26

mVpp

3 000 000

0.09

mVpp

10 000 000

0.23

mVpp

100 000 000

3.0

mVpp

Table 9.2. Required power supply ripple specification for VIO_3.

LC filter solution

When the VIO_3 voltage source is connected to a switching power supply, a post LC filter as

displayed in Figure 9.3 can be designed satisfy the ripple specification. The exact values for LC filter

depend on switching frequency and ripple amplitude of the supply regulator. Be aware of LC filter

peaking at the series resonance frequency f=1/(2π

√������������). A small snubber resistor, 250 mΩ in the

example filter, can be inserted to lower the Q factor.

VIO_3a,b

22uF

2.2uH

250 mΩ

Supply

100nF

Figure 9.3. LC supply filter.