• State Resolved
  • Replies 1 reply
  • Subscribers 34 subscribers
  • Views 28 views
  • Users 0 members are here
Support feedback
Options
Options
Related

TRS3232E: Start-up Time from VCC Power-Up to Reliable RS-232 Communication

Yuta Nishie
Mastermind 6160 points

Part Number: TRS3232E
Other Parts Discussed in Thread: TRS3222E

Hi,

I am considering power-cycling the TRS3232EIPWR by supplying VCC only when RS-232 communication is required, in order to reduce the overall power consumption of our board.

Could you please clarify the required start-up time after VCC is applied?

Specifically, I would like to know the minimum waiting time from VCC power-up until the device is ready for reliable RS-232 communication.

I could not find a power-up/start-up time specification in the datasheet. Is there a characterized value or recommended delay before starting communication after VCC is applied?

Best Regards,

Nishie

  • +1
    TI__Expert 3620 points

    Hi Nishie,

    I'd recommend taking a look at our TRS3222E which has an built in "Powerdown" logic pin that puts the device into an ultra-low power mode without having to ramp down VCC, it might be easier to implement in your system.

    Unfortunately we don't characterize the "turn on" time of either transceiver. For either one (the TRS3232E by toggling VCC or TRS3222E by toggling PWRDOWN) the point that you could consider them "ready" for communication is when the charge pumps are fully charged and active. This would be when V+ and V- hit their steady state voltage (~ +/- 6V). This depends on the ramp rate of VCC and also the stability of its voltage, and so can vary from system to system. If I had to guess it would probably end up in the single digit millisecond range, but I highly suggest testing it on your own board to confirm.

    -Ethan White