• State Resolved
  • Locked Locked
  • Replies 8 replies
  • Subscribers 17 subscribers
  • Views 2549 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.

TS3A227E: clock generated internally?

Ryuji
Guru 20090 points
Part Number: TS3A227E
Other Parts Discussed in Thread: TS3A225E, TS3A226AE

Hi, 

Is the clock generated internally in the TS3A227E?
Is there a possibility of becoming a noise source giving RF sensitivity suppression?

In the customer, when using a USB/Audio SW IC of competitor , there is a charge pump and ring oscillator inside the IC, and the sensitivity suppression has occurred in the DTV band due to the influence.
They would like to confirm that there are concerns.

Best Regards,
Ryuji

  • 0
    TI__Mastermind 23485 points

    Hello Ryuji,

    If I understand correctly your customer intends to use this switch in some system for digital television(DTV). DTV can operate in the VHF, UHF, and SHF frequency bands ranging from 30MHz to 30GHz. Could you provide a little more detail as to what specific range of frequencies they are concerned about?

    The TS3A227E does have a charge pump and it also has an oscillator. However, the oscillator in this switch operates in the low KHz range while we suspect the competitor switch's ring oscillator operates at a much higher frequency.

  • 0 in reply to Patrick Simmons
    Guru 20090 points
    Hi Simmons san,

    Thank you for the reply.
    I'm checking the concerned frequencies. The application is smartphone. They are interested in the following TI design. www.tij.co.jp/.../tidub66.pdf

    The competitor switch's frequency is about 11MHz.

    Could you please let me know more detail of internal oscillator frequency ?

    Best Regards,
    Ryuji
  • 0 in reply to Ryuji
    Guru 20090 points
    Hello Simmons san,

    Please see the concerned frequency range as following.

    DTV： 470MHz ~ 710MHz
    Band17: 736.5MHz ~ 741MHz
    Band5: 26:859.7MHz ~ 893.3MHz

    Best Regards,
    Ryuji
  • 0 in reply to Ryuji
    Guru 20090 points
    Hello Simmons san,

    I got additional questions.
    Is the Internal oscillator always active if the device powered on?
    Is the charge pump used for? Please let me know if possible.

    Also, is the following audio switches have internal oscillator too?

    TS3A26746
    TS3A225E
    TS3A226AE

    Since the TS3A227E have Key press detection function.
    I think that if the charge pump was used for key press detection function, above devices don't have internal oscillator.

    Best Regards,
    Ryuji
  • 0 in reply to Ryuji
    TI__Mastermind 23485 points
    Hello Ryuji,

    The TS3A227E's oscillator is active as long as the device is powered. It is used for passing information among the device's internal registers. The frequency of operation is 32kHz.

    The other devices have different architectures and the role of charge pump and frequency of the oscillators may be different. Currently I am still trying to get a little more information with regard to those.
  • 0 in reply to Patrick Simmons
    Guru 20090 points
    Hello Simmons san,

    Thank you for your support.
    I'm looking forward to the information.

    Best Regards,
    Ryuji
  • 0 in reply to Ryuji
    Guru 20090 points
    Hello Simmons san,

    I am sorry, but I have additional questions.

    (1)
    From your reply, the internal oscillator is used for passing information among the device's internal registers.
    Is this mean the internal Charge pump is used for internal registers?

    (2)
    What pin is near the internal oscillator?

    Currently our customer check the noise spectrum of TS3A227E on the EVM.
    They don't connect the EVM to the MCU.
    They want to know the location of the internal oscillator to check the precise noise level.

    Best Regards,
    Ryuji
  • 0 in reply to Ryuji
    TI__Expert 6395 points

    Hello Ryuji-san

    1) The internal oscillator is on when the device is not in sleep mode, when an accessory is plugged in or in manual control mode.  I cannot give more information on the charge pump use case as this is proprietary IP of TI.

    2) I cannot give this information on our device.

    I can tell you that this is a low power device and as such the operating frequency of these components is no where near your application use case.  We take great care to ensure that our internal components have no effect on the external I/O pins, especially as this is an audio device and any noise is immediately heard by the end user.

    Hope this helps.

    Regards,

    Andrew