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TPS659037: OSC16MIN inqueries

Kazuki Itoh
Genius 9375 points
Part Number: TPS659037

Hi team,

1. Does TPS6590379ZWSR work without 16.384MHz or 32kHz clock when OSC16MIN is grounded?

2. Could you let me know the definition of the bypass mode of OSC16MIN in pin functions section in the datasheet?


To tell you the detail and background, my customer saw TPS6590379ZWSR outputting the voltage correctly when OSC16MIN is grounded.
However, from the datasheet 6.2.2.9, it looks like the device is not supposed to work without the external 16.384MHz clock.

> Please note that if the OSC16M_CFG OTP bit is set to 0, a 16-MHz crystal must be present for the proper operation of the device.

My customer found the similar question on E2E.
https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1122692/tps659037-internal-oscillator-setting-osc16m_cfg/


> How can we enable 32kHz internal oscillator whereas OSC16M_CFG is R only?
The OSC16M_CFG bit is automatically set by the OTP configuration so there is no way to change it.

TPS6590379ZWSR is OTP 97 version.
OTP 97's OTP bits are described in the thread below.

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1170454/tps659037-pmic-ic-default-output-voltages/

My customer would like to make sure which one is correct, measurement or datasheet or E2E thread.


3.Instead of supplying clock to OSC16MIN and OSC16MOUT with the crystal, is it OK to input the clock from the oscillator operating with 1.8V which is same as VRTC?
The E2E thread below rejected 3.3V oscillator and recommended to use crystal.
https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/788699/tps659037-regarding-the-connection-of-the-oscillator-not-the-crystal

But 1.8V oscillator use case is not discussed, so my customer would like to check if it works.


Best regards,
Kazuki Itoh

  • 0
    TI__Genius 9880 points

    Hi Kazuki,

    the device expert was out last week but is back now and should give you a reply on Monday or Tuesday.

    regards,

    Niko

  • 0 in reply to Niko Alatalo
    TI__Mastermind 35490 points

    Hi Kazuki,

      I need more time to check some documents and maybe other team members; and then reply you tomorrow. 

    Thanks!

    Phil

  • +1 in reply to Phil Yi40
    TI__Mastermind 35490 points

    Hi Kazuki,

      My feedback are listed below:

    1. If the application does not require an accurate system clock for the processor, then providing one to the PMIC is not required. This option produces a lower quiescent current as seen in Section 4. In this configuration, the OSC16MIN pin should be grounded, while the OSC16MOUT and OSCMCAP pins can be left floating.
    2. The when OSC16MIN is grounded; the RTC function is in bypass mode. The 16-MHz crystal is not required for operation of the TPS659037 device with the OSC16M_CFG OTP bit is set to 1. 
    3. Yes; it's OK to input the clock from the oscillator operating with 1.8V.

    Thanks!

    Phil