TPS55289: Request for Circuit Review and Technical Clarifications

Hi Jeong,

Thank you for reaching out. I will look into this later today.

Regards,

Mulin

Hi Mulin

I accidentally clicked "Solve" earlier...

Can you mark the value and rated voltage for each part? I cannot find some of the part number.
   -> ex) RC1005J105 : 1005 size 100Kohm
   -> ex) CS1005X5R105 : 1005 size 1uF

Can you provide datasheet of the output caps?
   -> Are you asking for the datasheet of the MLCCs?
   -> Except for the tantalum capacitor, all other capacitors are MLCCs.

What is the input voltage range? Is output rnage 5-9V, 3A? Is this a PD application?
   -> I am considering 12V for the input. Would 24V input also be possible?
   -> For the output, I am considering a maximum of 9V.
   -> Yes, this is a PD application. I plan to control it via I2C communication with the PD controller.

Usually we don't recommend to use tantalum capacitor because of large ESR. Do you consider to use a hybrid capacitor
   -> I am not currently using hybrid capacitors. Previously, I used tantalum capacitors to resolve ringing issues when using another company's PD Buck Boost IC.
   -> Is a high-capacitance capacitor essential in this case?

Regards.
Jeong.

Hi Yongki,

Yongki Jeong1 said:

 -> ex) RC1005J105 : 1005 size 100Kohm

I think 105 refers to 1Mohm? Can you generate schematic with the valuw?

Yongki Jeong1 said:

   -> Are you asking for the datasheet of the MLCCs?

Yes, I want to check effective capacitance, so I need the part number or datasheet.

Yongki Jeong1 said:

I am considering 12V for the input. Would 24V input also be possible?

It is possible, we only need to verify the loop parameters. What is the error range of the fixed voltage?

Yongki Jeong1 said:

   -> I am not currently using hybrid capacitors. Previously, I used tantalum capacitors to resolve ringing issues when using another company's PD Buck Boost IC.
   -> Is a high-capacitance capacitor essential in this case?

Do you have low temperature requirement? If not 300mohm ESR of the T-Cap is ok. Recommend to reserve the high-capacitance for better transient performance.

Regards,

Mulin

Hi Mulin

1. Sorry, my mistake. 1M is correct.
The schematic values ​​are calculated values.

2. For 12V input, the dropout is around 0.6V, and for 24V input, it’s about 1V.

3. I am considering an operating range of 0–45°C.
I will also consider using products with low ESR.

Are there any other issues with the schematic?

Regards.
Jeong.

Hi Yongki,

1.Make sure SCK and SDA are pulled up.

2.MODE pin and COMP pin connection are wrong. Connect R10958 and R10962 to MODE pin. Connect compensation network to COMP pin. Recommend to to add a cap parallel to C10314 and R10961.

3. Add RC filter between ISN and ISP.

4.Add RC snubber in SW1 and SW2.

Yongki Jeong1 said:

Is it necessary to separate AGND? Does AGND apply only to analog components?

• I am using audio, but the distance is over 50mm.

Yes, recommend to use separate AGND. Only for signal pins of TPS55289. Please refer to layout guideline.

4201.TPS55289 Layout Guideline.pdf

Yongki Jeong1 said:

Are the BOM components of the EVB in inch units?

Yes.  The left column.

Yongki Jeong1 said:

Can I use 0.5mm vias under TPS?

For reference, EVM use 0.4572mm diameter and 0.2mm for hole size. 0.5mm is ok.

Yongki Jeong1 said:

For the blue line shown in the picture, how much spacing is recommended?

For reference, EVM use 0.2286mm distance.

Regards,

Mulin

Hi Mulin

Thank you for your kind response.

When running Webench, neither the snubber nor the parallel capacitor was included.

- Is the snubber circuit mandatory, or is it just reserved space for debugging?

- Can I refer to the EVB for the parallel capacitor values?

- I would like to request a review regarding replacing the tantalum capacitor with an electrolytic capacitor.

  - 100uF, 50V, J10, ESR 0.25 ohm

BXJ.pdf

- Please refer datasheet of MLCC

SAMSUNG MLCC.pdf

- Do you have a USB PD reference circuit that uses the 55289?

   I am confused about the connection between AGND and PGND.

          > How do you connect the separated GND from the USB-C connector?

          > Does DGND, which includes the USB IC, also fall under AGND?

Regards.
Jeong.

Hi Yongki,

Due to bandwidth limitation, I will look into this later.

Regards,

Mulin

Hi, Mulin

I would like to request your review to confirm if both products shown in the attached images are compatible.

If possible, I prefer to use the 6045 product.

Regards.

Jeong.

Hi Jeong,

For TPS55289, recommend to use inductor with Isat>8A since average inductor current limit is 8A. In some transient occasions like start up and load transient, inductor current will rise. If Isat is not enough, it may saturate and cause damage.

Regards,

Mulin

Hi, Mulin

I am considering a USB PD specification with a maximum charging current of 3A.

Using this specification, I ran Webench and reviewed the recommended materials as shown below.

Is an Isat of 8A mandatory in this case?
If so, the inductor becomes significantly larger.

Regards.

Jeong.

Hi Jeong,

Webench simulation is for reference. Recommend to follow my advice and choose 8A inductor.

Regards,

Mulin

Hi Mulin

I found a TPS55287 product with the same package for 4A output.

When changing to 55287,

1) Can I use the inductor I asked about before?
2) Is it possible to change Pin to Pin without changing the circuit?

Regards,

Jeong

Hi Mulin

Thank you for your kind guidance.
I wish you success in everything you do!

Best regards,
Jeong