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Original question:

TXS02324: Circuit Check

TXS02324: VDDIO and setting Question

Julian Chen
Expert 2550 points
Part Number: TXS02324

Hi E2E,

1. The power domain of Pin9~17 is refer to VDDIO(1.7V~3.3V). But the VIH(Max) of these pins is only 1.9V, does it means that these pins only support 1.8V(Class C) input voltage?
If baseband could supply 3V VDDIO(Class B) then it does not make sense that Pin9~17 are limited to 1.9V Max input voltage.
If we need to support 3V(Class B), the VDDIO and Pin9~17 should be supplied in 3V, right?

2.
The System default would start in 1.8V mode, but while the baseband is configuring in 2.95V, there is lack of communication between the baseband and the SIM card, so does the TXS02324 will configure itself to 2.95V automatically or need baseband to control I2C and assert B1=1 in the SIM interface Control Register to finish this voltage transfer?

Does the setting up SIM interface sequence shown as below all depend on Baseband to change register bits to be properly setup?

Thanks!

  • 0
    TI__Guru 58320 points
    hi Julian,

    The Vih is given as the min spec only without any max and yes, the max should be the Vcc supply.
    Since the control and the IO ports are overvoltage tolerant, you can have max at 3.3V even with Vddio at 1.7V.

    The baseband controls the communication and configuring the 2.95V selection through the B1 bit.
  • 0 in reply to ShreyasRao
    Expert 2550 points

    Hi Shreyas,

    Thanks for you rebply.

    About my question and your reply,
    Q: "The System default would start in 1.8V mode, but while the baseband is configuring in 2.95V, there is lack of communication between the baseband and the SIM card, so does the TXS02324 will configure itself to 2.95V automatically or need baseband to control I2C and assert B1=1 in the SIM interface Control Register to finish this voltage transfer?"
    A: "The baseband controls the communication and configuring the 2.95V selection through the B1 bit."

    The reply means TXS02324 will auto detect baseband's voltage and control B1 to set 2.95V OR baseband need to set(Control from baseband) B1 to 2.95V?

  • 0 in reply to ShreyasRao
    Expert 2550 points
    Soft Remind!
    Thanks!
  • 0 in reply to Julian Chen
    TI__Guru 58320 points
    Hi Julian,

    The baseband needs to set B1 to 2.95V.