Schematic - Broadcom AFBR-S50 Reference Design

AFBR-S50 Time-of-Flight (ToF) Sensor Family Application Note
The MKL17Z256VFM4 MCU has the following mechanical characteristics:
32 QFN

5 × 5 × 0.65 mm (W × L × H)

0.5-mm pitch
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Link to the data sheet:
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CAUTION! Laser Class 1 operation depends on the correct system integration and configuration of the software. Without
the correct configuration or before the integration has been completed, the module can emit at higher levels
and is rated as the Laser Class 3B device!

2.1 Schematic

Figure 2 shows the schematic of the AFBR-S50-RD.
The input voltage for the AFBR-S50-RD is 5V, and it is distributed to the circuit via the pin 1 of the J1 connector
(FTS-111-02-F-S, a single-row 11-pin header with 1.27-mm/50-mil pitch).
However, the operating voltage of the Kinetis KL17Z MCU is within the range from 1.7V to 3.6V. To facilitate the power
requirements of the Kinetis KL17Z MCU, an additional low-dropout voltage regulator (LDO) must be used. For this purpose,
the AFBR-S50-RD uses the TPS79901-EP, an ultra-low noise LDO from Texas Instruments, configured to reduce the voltage
from 5V to 3.3V. It can deliver up to 200 mA with a negligible voltage drop of 100 mV, which is more than enough for the
proper operation of the Kinetis KL17Z MCU. The 100-nF and 10-nF bypass capacitors on both VDD (pin 15) and VDDA
(pin 7) power supply pins positioned next to the MCU itself provide the additional MCU voltage stabilization.
Two open-drain, active LOW nIRQ and nRESET signal pins (pin 17 and pin 19, respectively) are pulled up to the 3.3V supply
rail using 10-kΩ resistors. Other pin definitions and functions of the Kinetis KL17Z MCU are listed in the system connection
overview table in Section 2.3, System Connections
The ARGUS-S50 (AFBR-S50MV85G) ToF sensor uses 5V for its operation, so it does not require additional voltage
reduction. However, due to the dynamic power consumption nature of its VCSEL driver, the sensor may introduce significant
voltage ripple and noise while operating. If not properly filtered, this might cause the power supply noise to be coupled back
to the application circuit and the sensor module itself. The filtering network consists of several bypass capacitors and a ferrite
bead, forming a pi filter. Minimum electrical xtalk values can be achieved by shorting GND and GNDL. The filtering network
is designed according to the circuit and layout recommendations from the AFBR-S50MV85G data sheet (the Application
Circuit and Layout Recommendations chapter).
The AFBR-S50MV85G data sheet can be downloaded from the following location:
https://docs.broadcom.com/docs/AFBR-S50MV85G-DS
Broadcom
https://www.nxp.com/docs/en/data-sheet/KL17P64M48SF6.pdf
Overview.
Reference Design
AFBR-S50-RD-AN100
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