TPS65910 with AM3352

Hirotaka Matsumoto

Other Parts Discussed in Thread: TPS65910, AM3352, TPS65910A

Hello,

We'd like to ask about TPS65910.

<Question1>
On the document 「am335x_evm_15X15 baseboard.dsn」, why doesn't the VDD3(SW3) connect to Vbus of AM3352?
So, the source VDD3(SW3) is DC-DC voltage, does't it fit for USB power?

<Question2>
On the document 「TPS65910Ax User's Guide for AM335X processor」,
pull up resistanse of SCL and SDA is 1.2kΩ.

When we use only Fast mode or slave mode, how much value of resistance should we use?
In case of only using Fast mode (400 Kbps) : XXkΩ
In case of only using slave mode(100 Kbps) : XXkΩ

<Question3>
We could not find out the content of rush current of the TPS65910A.
If the value of the rush current is higher than the value of over rated current, what will the device behave?

Kind regards,

Hirotaka Matsumoto

over 11 years ago

0 Biser Gatchev-XID over 11 years ago

TI__Guru**** 393215 points

Hi Matsumoto-san,

Q1: SMPS3 is rated for 100mA maximum output current, which makes it unsuitable for VBUS source. Note that the AM335X VBUS pin is a sense input only.

Q2: 1.2kOhm to 4.7kOhm are used on different AM335X reference designs. See http://processors.wiki.ti.com/index.php/AM335xBoards for schematics.

Q3: You can turn to the http://e2e.ti.com/support/power_management/pmu/f/43.aspx forum for more precise TPS65910A information.

0 Hirotaka Matsumoto over 11 years ago in reply to Biser Gatchev-XID

Guru 27585 points

Biser San,

Thank you for your prompt reply.

We'd like to confirm about Q1.
We mentioned that Vbus means USB's Vbus of AM335X.
Will the answer become the same?

Kind regards,

Hirotaka Matsumoto

0 Biser Gatchev-XID over 11 years ago in reply to Hirotaka Matsumoto

TI__Guru**** 393215 points

For Host mode the AM335X board must be able to source 500mA on the USB connector. This is done through a power switch controlled by the USBx_DRVVBUS signal. VBUS from the connector is fed back to the USBx_VBUS processor pin.

For Device mode VBUS is sourced from the USB connector and is tied to the USBx_VBUS pin.

0 Hirotaka Matsumoto over 11 years ago in reply to Biser Gatchev-XID

Guru 27585 points

Biser San,

Thank you for your prompt reply.

Q1 : We understood your saying.

Q2 :  1.2kOhm to 4.7kOhm are used on different AM335X reference designs.
        Our customer will use AM3352 processor.
        How much value of resistance should we use?
           - In case of only using Fast mode (400 Kbps) : XXkΩ
           - In case of only using slave mode(100 Kbps) : XXkΩ
        We could find out these on the WEB-site.

Q3 : We will check about Q3 on TPS65910 forum.

Kind regards,

Hirotaka Matsumoto

0 Biser Gatchev-XID over 11 years ago in reply to Hirotaka Matsumoto

TI__Guru**** 393215 points

Q2: Pullup resistor values calculation for I2C is described in the I2C specification, which can be freely downloaded from a lot of sources on the Internet.

0 Hirotaka Matsumoto over 11 years ago in reply to Biser Gatchev-XID

Guru 27585 points

Biser San,

Thank you for your updata.
We see the data sheet.

Kind regards,

Hirotaka Matsumoto

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TPS65910 with AM3352