dc2dc buck

Hi Lazer,

Please create separate post for different devices. Then each support engineer will see the post and help you.

I only support TPSM8S6C24, I would recommend 4 phases in stack for 100A application since TPSM8S6C24 the max output current is 35A with is pretty close to 100/3=33.3A. The device temperate is very higher if you don't have forced airflow. If you really want 3ph, I can provide the reference design schematic.

Thanks,

Nancy 

hi nancy 

first thanks 

regard utilize this component TPSM8S6C24 to support 100amp, I have more voltage to support 0.85v 100amp , 0.9v 30amp , 1.2v 30amp ,3.3v 30amp 

I think for production it more convenient to have one part in the BOM to support all, and I will need 75-80amp but to be in safe side I design to get 100amp  

regard efficiency, when I set the module to 0.85v I get efficiency ~77%, I understand it create heat and for that need to good air flow 

how can I increase the efficiency, but without spoil the output voltage ? 

one more issue and to be sure,

I need to set the module to correct power without PMbus, do I able to do so? later when the board is working I will have PMbus ...

thanks

lazer 

Hi Lazer,

1. For 75A-80A, you can use 3ph stack. 

2. Where did you get efficiency ~77% for 0.85V? Your own board or TI EVM? What is the switching frequency setting and DCR of output inductor? From the Figure 7-2 in the datasheet, we can get 80% efficiency for 0.8V, 0.85V should be higher than 80%.

3. Yes, you can set the correct configuration with pinstrap only and no PMBus. You can have three PMBus lines (CLK/DATA/ALERT) to access PMBus during debug stage or needed.

4. Do you have schematics for 0.85V/100A, 0.9V/30A, 1.2V/30A, 3.3V/30A? Do you want me to create those reference design schematic for you?

Hope this helps,

Thanks,

Nancy

hi Nancy 

o.k. 

one by one 

I run the WEBbanch (0.85v, 35amp, 650Khz) and got this 77.3%, also I try 25amp and got 82%.

means 35amp X 0.85v X (100%- 77%) /100% = ~6.8watts   

means 25amp X 0.85v X (100%- 82%) /100% = ~3.8watts   

as you said, we need a good air flow a

yes, can you send schematic for the 0.85v 100amp ,0.9v 30amp 1.2v 30amp .3.3v 30amp includes the resister that define the output voltage 

regard production 

since this module is new, can I assume, the longevity for this is 10years from 2023, means it will be till 2033?

what is the MOQ, lead time ?

regard the price I understand for Israel, I can buy them from digikey, mouser, do you have others? 

thanks

lazer 

Hi Lazer,

1. Could you give me the detail design requirement for each rails? Efficiency target, output ripple and load transient etc? I recommend set 550kHz switching frequency to increase efficiency. I can generate the reference design schematic, BOM and calculation tools in a few days after receiving your requirement. You may send the detail to my email. nancy_zhang@ti.com. We can discuss offline.

2. TI products are not eligible for obsolescence if the product has any current customer demand. 

3. I am not sure about the MOQ lead time and price. I suggest you work with your salesperson or TI support at Customer support center – Homepage - Customer Support (service-now.com) for non-design questions.

4. The device can be purchased through TI or TI store directly. Please refer to items as above.

Hope this helps,

Thanks,

Nancy

hi Nancy

the project contains Intel agilex 7 and from there I take those number. 

all parameters are (+) (-), those parameters are for the module, then I need to add some because of routing.pcb ... 

voltage    cornet       Accuracy    Ripple       total 

0.85v      100amp        0.5%        2.0%         2.5%   

0.9v          30amp        0.5%        2.0%         2.5%

1.2v          30amp        1%           3.0%          4%

3.3v          30qmp        1%           3.0%          4%

for the 0.85v I think to take 4 modules, because the total dissipation goes down from 20w to 15w 

for other voltage/module, do I need to open the same session. 

thanks

lazer 

Hi Lazer,

Does total means total tolerance including load transient? Could you load transient spec for each rails? including load step and slew rate. The load transient step and slew rate affect output capacitance selection.

Thanks,

Nancy

hi 

the total mean for example    0.85v      100amp        0.5%  +  2.0%  =  2.5%  from the nominal voltage 

regard load time they (intel) ask the power will come up in smooth way without "plato" 

from what I see in the example design they its around 3-5ms, 

also they require power sequence but this on me 

other thing, since the major clint for this device is intel FPGA, the real demand for power will be after all power rail are o.k. 

only then we start load the "running code", when finish load the fpga start working, than the module need to support the full power

thanks

lazer  

Hi Lazer,

The load transient step and slew rate is not 3-5ms duration. For example, 0.85V at some scenarios, load change from 0A to 25A at 1us (25A/us slew rate). This sudden change may cause output voltage overshoot and undershoot due to loop response delay. So need to add more output capacitance to support. Intel should have the requirement for overshoot/undershoot, load step and slew rate. If you don't have that number, I will assume 25% load change for each rails to generate the schematic. You may fine tune on your validation stage. 

What do you think?

Thanks,

Nancy