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SBC recommendation

Other Parts Discussed in Thread: TCAN4550-Q1, TCAN1162-Q1, TCAN4550

Hi,

I got a inquiry about recommendation of SBC in LDM.

Could you please recommned some SBC devices that is fit on their requirements?

Requirements:

Max supply current : larger than 80mA

The channel of HS CAN : more than 1

Functions : Watchdog, Wake up

Could you recommend some devices?

Thank you.

Best Regards,

Kevin Shin

  • Kevin,

    For the Max supply current, you're referring to an integrated power supply that can output 80mA, correct?

    The best fully-released option we have right now is the TCAN4550-Q1. It has an integrated LDO that supplies the CAN bus, but can also support 70mA output, only has one CAN channel, watchdog, and wake up features. It also comes with a controller integrated, so this would probably be over-designed for what is needed.

    The next best option would be the TCAN1162-Q1 which is sampling, but this does not include watchdog and only has one CAN channel.

    We have another device on the way, but it is still early in the development cycle. It has watchdog, wake up, LDO capable of 100mA, but again, only one CAN channel. You can email me directly if you want more specific information on this device.

    Please let me know if you have any other questions.

    Regards,

  • Hi Eric,

    Thank you for your recommendation.

    So you recommended TCAN4550-Q1. I have a question about this device.

    Can MLCC be used to output of LDO in TCAN4550-Q1?

    If it is possible, what is the value of MLCC capacitance you recommend?

    And is there any short circuit protection to the output of integrated LDO?

    Thank you.

    Best Regards,

    Kevin Shin

  • Hi Kevin,

    I am a colleague Eric's and will help you out while he is out of the office.

    Yes, MLCC capacitors can be used on the output of the LDO. 

    The TCAN4550 has a 5V LDO that provides power for the integrated CAN transceiver and the VCCOUT pin for a total available current of 125 mA.  The amount of current that can be sourced is dependent upon the CAN transceiver requirements during normal operation.  When a bus fault takes place that requires all the current from the LDO, the device is not able to source current to external components.  During sleep mode this regulator is disabled and no current is provided.  Once in the other active modes the regulator is enabled for normal operation.  This pin requires a 10 uF external capacitor (minimum) as close to the VCCOUT pin as possible.  See the Power Supply Recommendations section in the datasheet for more information.

    The only short circuit protection feature on the LDO output is the Thermal Shutdown feature of the device.  This is a device preservation event.  If the junction temperature of the device exceeds the thermal shut down threshold, the device turns off the internal 5 V LDO for the CAN transceiver thus blocking the signal to bus transmission path as well as turning off the ability to source current and voltage to the VCCOUT pin.  A thermal shut down interrupt flag is set and an interrupt is inserted so that the microprocessor is informed.  If this event happens, other interrupt flags may be set.  If this event happens the digital core and SPI interface are still active.  After a time of approximately 300 ms, the device checks the temperature of the junction.  The thermal shutdown (TSD) timer starts when TSD fault event starts and exits to standby mode when a TSD fault is not present when the TSD timer is expired.  While in thermal shut down protected mode a SPI write to change the device to either Normal or Standby mode is ignored while writes to change to sleep mode is accepted.  If a thermal shut down event happens while the device is experiencing a VIO under voltage event the device enters sleep mode.

    Regards,

    Jonathan