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BGT60ATR24C ES shield
XENSIV™ 60 GHz radar system platform
Hardware description
3
Hardware description
This section of the document presents a detailed overview of the BGT60ATR24C shield's hardware specifications.
It covers BGT60ATR24C considerations, as well as the power supply, oscillator and board interfaces.
3.1
Overview
Figure 2
Top and bottom views of the BGT60ATR24C shield
The dimensions of the BGT60ATR24C shield are 26 mm x 16 mm. The BGT60ATR24C sensor is mounted on top
of the PCB, while on the bottom patch antennas have been located. The current design of the shield uses two
Rogers laminate layers for top and bottom (RO3003 top and RO4350B bottom). More details of the PCB stackup
are mentioned in section 3.6.
To provide the correct level shifter voltage for the MCU board, the 1.8 V
refer to "Level shifters" section of application note AN599 [1]. When the shield is plugged into the Radar
Baseboard MCU7, the sensor's supplies are initially deactivated. Only the EEPROM is powered. The
microcontroller will read the content of the EEPROM's memory to determine which sensor is plugged into the
sensor interface. Actually, it is not mandatory to use this EEPROM with the BGT60ATR24C, as it has an internal
chip ID which can be read by SPI directly. The EEPROM is only for ensuring compatibility with other Infineon
chips that do not have the chip ID feature.
Radar sensors are very sensitive to noise and cross-talk on the supply domains. Therefore, the different supply
domains must be decoupled. On the BGT60ATR24C shield, this is realized by a pi-shaped low-pass filter on each
supply domain (and the oscillator supply). Communication with the radar sensor is mainly performed via a
serial peripheral interface (SPI) bus. Additionally, two more digital lines are required for operation. One line
signals the microcontroller when new data needs to be fetched. The other allows the microcontroller to
perform a hardware reset of the sensor. Furthermore, an LED indicator is mounted on the board. This allows
the microcontroller to signal (for example) if the sensor is activated or deactivated at that time.
3.2
Sensor supply
Since radar sensors are very sensitive to supply voltage fluctuations or cross-talk between different supply
domains, a low-noise power supply with properly decoupled supply rails will prove vital. The Radar Baseboard
MCU7 provides a low-noise supply (see section 2.2 of application note AN599 for further details). Figure 3
depicts the schematics of the pi-shaped low-pass filters employed to decouple the supplies of the different
Application note
Top view
26 mm
supply line is connected with V
sensor
5
Bottom view
Revision 1.10
–
digital
2023-02-14
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