Figure 14 Baseband Frequency Response For Low-Gain And High-Gain Stages; Table 2 Baseband Amplifier To Mcu Pin Connections; Table 3 Baseband Amplifier Components And Settings - Infineon BGT24LTR11 Manual

Distance2GoL (Software-Controlled FMCW) low-power radar shield using
BGT24LTR11 for range detection and human tracking
Hardware description: BGT24LTR11 Shield
The offset of the low-gain signal equals the static offset of the BGT output signals. Due to the DC block at the
beginning of the second stage, the offset of the high-gain signal matches the reference voltage of 1.65 V. As
shown in Figure 14, the first gain stage provides a gain of up to 30 dB (low-gain stage) and both the stages
together provide a gain of up to 57 dB (high-gain stage).
Figure 14 Baseband frequency response for low-gain and high-gain stages
Figure 14 shows the frequency response of the low- and high-gain stages. The BGT24LTR11 Shield allows the
user to select either the low-gain (first stage only) or high-gain (first stage + second stage) mode depending on
the target RCS and distance to be detected. The low-gain output is referenced to the individual mixer output
bias voltage (1.6 to 2.0 V), and the high-gain stage is AC coupled and referenced to V
Table 2 lists the MCU pins (on the Radar Baseboard XMC4700) associated with each of the gain stages. Use the
graphical pin select tool in the DAVE™ software to select the appropriate pins for signal processing.
Table 2 Baseband amplifier to MCU pin connections
XMC4700 – port pin
P14.6 (VADC.G0CH6)
P14.7 (VADC.G0CH7) / P14.3 (VADC.G1CH3)
P14.14 (VADC.G1CH6) / P15.3 (VADC.G2CH3)
P14.15 (VADC.G1CH7) / P15.9 (VADC.G3CH1)
The gain and bandwidth of the IF stages can be manually configured by the user by changing the resistor and
capacitor values specified in Table 3.
Table 3 Baseband amplifier components and settings
IF stage
Stage 1
(low gain)
Application Note
Designator Gain
U5A 30 dB
Pin label
IF.I1
IF.Q1
IF.I2
IF.Q2
Configurable components –
I section
C16, R33, C17, R36
page 19 of 32
/2 = 1.65 V.
CC
Pin function
IFI – high gain
IFQ – high gain
IFI – low gain
IFQ – low gain
Configurable components
– Q section
C37, R65, C35, R61
2021-03-31
V1.0