TPS25830A-Q1: SPICE Model for Simulation

Hello Seong,

In the absence of SPICE model, can i use RDS_ON (4.3ohm) value for simulation? Along with RDS_ON, CIO_ON also include?

Provide a circuitry between DP/DM_IN to DP/DM_OUT.

This may helpful for our simulation.

Thanks,

Mani M

Hello Manikandan,

Yes, 4.3Ω is RDS_on for the DP and DM switch on-resistance. CIO_on, the DP/DM switch on-state capacitance is 10pF.

See the Functional Block Diagram for the DP/DM circuitry below.

• While in CDP mode, the data switches are ON, even during CDP handshaking.
• The data line switches are OFF if EN/UVLO is low.
• The data line switches are OFF if OVP is detected on data line

Hope this helps,

Seong

Hello Seong,

Ideally i used 4.3ohm resistance in USB lines, anyway i will use Cio capacitance also.

Additionally, in datasheet i saw the insertion loss is -3dB near 800MHz, i hope this large loss chances of degrade the eye diagram, when using USB cable (roughly 1.6m). Is there anyway to improve the performance of eye diagram or any other TI parts recommended with lesser insertion loss?

Thanks,

Mani M

Hello Seong,

Thanks for your updates.

Regarding LC network to DP/DM lines, how to choose those values? Whether the LC value depends on the USB cable?

For Eg., if i use 1.5m, 2m & 5m cable, the LC value constant for all USB cable length?

Thanks,

Mani M

HI Seong Yong Kim

Would you be able to generate the Spice model or S-parameter for this IC ?

Thanks!

Hello Seong,

In datasheet, the insertion loss mentioned as -3dB near 800MHz. How to include this data transmission loss in Simulation. Since i considered only RDS_ON value only. 

How the insertion loss plot derived? Can you share more information about this.

Thanks,

Mani M

Hello Aptiv team,

Unfortunately, I won't be able to help when it comes to generating a Spice model for this device. 

I believe a network analyzer was used to measure the insertion loss. I will see if I can reproduce the same measurement for DP and DM, and if successful, I will try to generate an SxP file to be used for simulation. However, it may take up to about a week before I can deliver this. Will two S2P files (one for DP and one for DM) or an S4P file work for you?

BR,

Seong

Hello Seong,

I need S4P file. The simulation model quite urgent & stopped our simulation.

Thanks,

Mani M

Hello Manikandan,

Noted. I will keep you posted.

BR,

Seong

Seong Kim said:

Noted. I will keep you posted.

This is 3years old request, where TI has commented S-parameters model is available.

https://e2e.ti.com/support/interface-group/interface/f/interface-forum/973652/tps25830-q1-ibis-model-s-parameter?tisearch=e2e-sitesearch&keymatch=TPS25830-Q1#

We believe both parts have similar insertion loss characteristics.  Can you help to get S-Parameter model for TPS25830-Q1?

Hello Akhilesh,

Yes, based on the network analyzer shots in their datasheets, I would expect their insertion loss to be more or less the same.

If I can generate the TPS25830A-Q1's touchstone file for you, I will also generate the TPS25830-Q1's touchstone file for you as well. 

BR,

Seong

Hello Seong,

In the absence of models, I have assumed RDS_ON (4.3ohm) value in Simulation. Can you confirm our assumption is valid?

Thanks,

Mani M

Hello Seong,

In the datasheet, the data transmission loss of -3dB measured @800MHz. In this measurement regards, can you clarify below queries.

1. At what electrical condition & mode of operation, the data transmission measured?
2. If the measurement is for ideal IC operating condition means, -3dB loss more & we cant able to achieve proper eye diagram as per USB standard. In this condition, -3dB is valid or how much of IC loss we should consider for simulation?

Thanks,

Mani M

Hello Seong,

We have an urgency & awaiting Simulation data. It blocking our simulation & production. Can you help me to get model ASAP.

Thanks,

Mani M

Manikandan,

Figure 8-29 is when the device is in Active Mode. Figure 8-28 shows the eye diagram when data is passed through the TPS25830A-Q1 data switch. This signal integrity is good and is a reflection of how a -3dB loss at 800MHz does not affect the Eye Diagram test, but this is with a 10cm cable.

The problem occurs when a 1+ meter cable is connected from the USB port to a front-end head unit. The parasitics of the cable will affect the impedance, thereby the signal integrity.

I am currently in the process of sourcing two 50ohm semi rigid cables. I will let you know once I have these on hand so I can begin using a network analyzer to capture the S-Parameter measurements and generate the S4P file.

My plan is to measure each data line separately and create two S2P files for each data line. Then I believe I will need to use MATLAB or a similar software to convert the two single-ended measurements to a single S4P. Considering what must all be done to deliver this simulation file, I'm not certain how quick the turnaround will be and may take another week or so.

BR,

Seong

Hello Manikandan,

I have the semi rigid cables and have identified a 4port network analyzer I can use at our lab. Is the S4P file something you still require?

BR,

Seong

Hello Seong,

Pls share the S4P file, this may helpful for our simulation.

Thanks,

Mani M

Hello Manikandan,

I have reserved time to use a network analyzer next Monday. I will provide the S4P COB on the 24th.

BR,

Seong

Hello Seong,

Any updates on S-Parameter file, i didnt receive any inputs from you.

Thanks,

Mani M

Hello Manikandan,

I've tried measuring the S-parameters with the TPS2583XAQ1EVM-147 using a network analyzer recently, but the results were not accurate. I believe it is because of the cables I was using. The conductor side that is soldered on the USB traces are exposed without much of the GND shield (see images below).

I will try again this week by cutting the conductor shorter, but I cannot guarantee that I will be able to deliver what I've committed to. For accurate measurements, we may need to design and build a board with on-board SMA connectors connected to the data pins for this very purpose. I will keep you updated.

BR,

Seong

Hello Seong,

Any updates on S-Parameter model? Since it blocking our design verification.

Request you to provide ASAP.

Thanks,

Mani M

Hello Manikandan,

I plan to take a 2nd try at the measurement tomorrow.

I'll let you know how the measurement turns out.

BR,

Seong