DS90UB954-Q1: schematic questions

Betty Guo

Part Number: DS90UB954-Q1

Hi team,

customer refer to the UB954 EVM scheamatic, they have some quesitons:

1. in 954 EVM sch, for POC, some components is hide. Is it unnecessary in the design?

2. for crystal oscillator, EVM use active crystal, and passive crystal oscillator is hide. can we use passive crystal instead of active?

attached customer schematic, can you help to review and give some comments? Ser is 953, Deser is 954

thank you

2311.DS90UB954.pdf

over 3 years ago

0 Hamzeh Jaradat over 3 years ago

TI__Guru* 94360 points

Hello Betty,

1) Can you specify which component do you mean?

Note that, on the EVM there are two types of PoC, one for 4G and another for 2G.

2) You can use either Oscillator or Crystal. This is descriped in the d/s.

For schematic review, please allow few days.

0 Betty Guo over 3 years ago in reply to Hamzeh Jaradat

TI__Expert 7300 points

Hi Hamzeh,

for question 1, I didn't find the POC type description on the 954 EVM user guide, only find there have two POC circuit for 953 and 933. I mentioned the component are L10 , L12, and R95.

0 Hamzeh Jaradat over 3 years ago in reply to Betty Guo

TI__Guru* 94360 points

Hello Betty,

L12 is a CMC, which could be useful if the customer is using differential pair and STP. For Coax it is not needed.

L10 is required only in the 2G PoC (when using with 933).

0 Betty Guo over 3 years ago in reply to Hamzeh Jaradat

TI__Expert 7300 points

thank you Hamzeh.

please also help to reivew the schematic, share your comments. thanks again.

0 Casey McCrea over 3 years ago in reply to Betty Guo

TI__Guru** 103215 points

Hello Betty,

Hamzeh will take a look at your schematic and share feedback within 2-3 days

Best Regards,
Casey

0 Hamzeh Jaradat over 3 years ago in reply to Casey McCrea

TI__Guru* 94360 points

Hello Betty,

I have reviewed your schematic and here are my comments:

- GPIO3/INTB pin required a 4.7k pull-up to VDDIO.

- If using Single Ended, RIN+ and - can't have the same capacitor value. Please refer to table 228.

- IDx pin: for an address of 0x3D, you need to change the resistors combination as per table 15.

- MODE pin: The resistors combination you are using is not valid. Please refer to table 2.

- PDB pin: please use a 10K instead of 36K PU.

- For VDD11_xxx pins, please replace all 10uF with 4.7uF caps.

- on VDD18_xxx pins and VDDIO pin, please use FB with DCR≤25mOhm; Z=120ohm@100MHz

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DS90UB954-Q1: schematic questions