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TIC10024-Q1: Schematic review request

Jeffrey Chung1
Expert 2705 points
Part Number: TIC10024-Q1

Dear Team,

I'd like to request the schematic review of TIC10024-Q1 for automotive application. Also, please check the component's values such as capacitor and resistor. Please refer to the attached file below.

Schematic_TIC10024-Q1.pdf

Regards,

  • 0
    TI__Mastermind 23050 points

    Hi Jeffrey,

    The decoupling capacitors on VS, VDD, CAP_A, CAP_PRE, and CAP_D look correct.  I would recommend having a larger capacitor value on the board closer to the supply for VS and VDD which I assume will be included in the design, but just not shown in this schematic.

    The SPI circuitry looks ok and it appears

    Reset is not used in this application, so pulling it low is correct.

    I'm not sure of the dual connection on the /INT pin between the C_SWITCH_INT and O_SWITCH_WAKE ports.  The /INT pin is an open drain that will pull low in the case of an interrupt.  There is a pullup resistor on the C_SWTCH_INT side of the blocking diode isolating the O_SWITCH_WAKE port.  I can't verify the purpose or accuracy of this from the portion of the schematic shared.

    It is common to have a series resistor values in the value of 100 ohms.  The 100nF capacitors seem a bit larger than I usually see and for example 0.015uF caps were used on the EVM.  However, without any information about your switches or device configuration, I can't verify their values will work with your desired configuration.  The inputs can be configured for sourcing or sinking current in different amounts and for different amounts of time.  The resistor, capacitor, and switch will create an RC filter that will change the amplitude of the pulse measured by either the comparator or ADC.  But since there are different threshold levels that can be set, there is a lot of flexibility.  But if the caps are too large, the voltage levels may fail to charge within the polling period resulting in low pulse voltage amplitude.  If you can provide additional configuration and switch information, I can provide more specific comments.

    Regards,

    Jonathan

  • 0 in reply to Jonathan Nerger
    Expert 2705 points

    Hi Jonathan,

    This device is used on the Integrated Central Control Unit for switching of door lock/unlock, seatbelt, trunk, tailgate, and etc. What is your recommended input capacitor value or range when input resistor value is 100ohm? 15nF to 47nF?

    Also, I will let you know after checking the dual connection on /INT pin.

    Regards,

  • 0 in reply to Jeffrey Chung1
    TI__Mastermind 23050 points

    Hi Jeffrey,

    The proper component values will need to be determined based upon the system level requirements and should be selected in such a way as to ensure the stability and accuracy of the measurement. 

    There are many factors that may need to be considered such as the resistance of the switch, the type of switch and whether it "bounces" as it is closed, the wiring between the switch and the MSDI device, whether the switch is to GND or to a supply, the amount of current used, the polling pulse width and the frequency of the pulses, etc.

    I would say that capacitors in the range of 15nF to 47nF would be more common that the 100nF caps shown in the schematic and these should be acceptable for the application you describe.  However, this needs to be determined by the customer and adjusted for their actual system application.

    Regards,

    Jonathan

  • 0 in reply to Jonathan Nerger
    Expert 2705 points

    HI Jonathan,

    I appreciate your kind explanation. It will help me understand this case.

    Regards,