• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 32 subscribers
  • Views 93 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

SN65HVD231: Supply current

Ram Sivanehru
Prodigy 10 points
Part Number: SN65HVD231

Hi,

Under section 8.5 electrical parameters, the maximum supply current is 17mA, does it mean,  even at  the highest CAN speed and for all operating temperature range this value won't go higher than 17mA.

Kind Regards

Siva

  • 0
    TI__Mastermind 48215 points

    Hi Siva,

    The specified currents in this section refer only to the current consumed by the transceiver itself (no load on the CAN bus). This does not include the current required to drive a differential across the termination resistance on the CAN bus. In a typical system containing a total differential load of 60-ohms, the driver current required to drive a 2V differential will be 33mA. In this dominant state, the Vcc pin of the transceiver will draw the current required to drive the differential (33mA) and the quiescent current for the transceiver (17mA max). Keep in mind that the recessive state of the driver requires far less current (negligible compared to quiescent) because no differential is driven across the bus load. The transceiver will spend roughly half of the time in each of these drive states while actively driving the bus, and remain only in the the recessive state when idle (not transmitting data). Therefore, the average power consumption can be estimated as the average of these currents:

    Pavg(transmitting) = (Idom + Iq  +  Irec + Iq) / 2 = (33mA + 17mA  +  0mA + 17mA) / 2 = 33.5mA

    This is still a fairly simplified explanation as this topic is fairly complex. This E2E post goes into more detail. 
    https://e2e.ti.com/support/interface-group/interface/f/interface-forum/246035/wattage-requirements-for-can-bus-terminating-resistor-with-sn65hvd233?tisearch=e2e-sitesearch&keymatch=SN65HVD255 

    Let me know if you have any more questions.

    Regards,
    Eric Schott