Hardware description
5
SLLU216 – July 2019
Copyright © 2019, Texas Instruments Incorporated
SPI to CAN FD SBC + LIN Transceiver BoosterPack User's Guide
The board uses a 30-V Zener diode as protection from excessive supply voltages, along with a reverse-
blocking Schottky diode and other EMC-filtering components on this supply voltage commonly found in
system applications. The board refers to the raw voltage supplied to the board as V
BAT
to correspond with
a system battery voltage, and the voltage after the supply filter as V
SUP
which is the actual voltage supplied
to the device pins. It is common to supply both a supply voltage and the bus communication through a
single wire harness and this supply voltage can be supplied through pin 9 of the DB9 connector J7, or
from a standalone supply through the DC barrel jack J2. Header J1 allows a shunt to be placed between
the center pin and the selected voltage source.
2.1.2
TCAN4550-Q1
2.1.2.1
V
SUP
Pin
The TCAN4550-Q1 is powered through the V
SUP
pin and supplies the internal regulators for the digital
core, CAN transceiver, and optional V
CCOUT
. A 330-nF capacitor is required on the LDO Filter pin FLTR for
proper operation as described in the data sheet and seen in the schematics.
2.1.2.2
V
IO
Pin
The V
IO
pin provides the digital I/O voltage to match the MCU I/O voltage to prevent the need for level-
shifting of signals across different MCUs. The V
IO
pin supports the SPI I/O pins, GPIO1 and GPO2 pins,
as well as the oscillator block supporting the crystal oscillator or CLKIN pins.
2.1.2.3
V
CCOUT
Pin
The TCAN4550-Q1 devices provide up to 70 mA of current on the V
CCOUT
pin from the 5-V internal LDO
without impacting the CAN transceiver performance, except when in sleep mode and when the regulator is
disabled. This voltage can be used to power an MCU or other supporting circuitry that is not needed
during sleep mode. At least 10 µF of capacitance to ground is required on the V
CCOUT
pin, as described in
the data sheet and seen in the schematic.
2.1.2.4
GND Pin
The thermal pad and pin 13 of the TCAN4550-Q1 device are ground and are connected to the ground
plane of the board to support heat dissipation.
2.1.3
TLIN2029-Q1
2.1.3.1
V
SUP
Pin
The TLIN2029-Q1 is powered through the V
SUP
pin which is typically connected to the battery through an
external blocking diode (D1) and is included in this design. If there is a loss of power on the board, or the
board is put into Sleep Mode, the device has extremely low leakage from the LIN pin and does not load
the bus down. This is optimal for LIN systems in which some of the nodes are unpowered (ignition
supplied) while the rest of the network remains powered (battery supplied).
2.1.3.2
GND Pin
GND is the TLIN2029-Q1 ground connection. The device can operate with a ground shift as long as the
ground shift does not reduce the V
SUP
below the minimum operating voltage. If there is a loss of ground at
the ECU level, the device has extremely low leakage from the LIN pin, and does not load the bus down.
This is optimal for LIN systems in which some of the nodes are unpowered (ignition supplied) while the
rest of the network remains powered (battery supplied).
