XC7K325T Low cost Power management

[ali_asadzadeh]

Hi,
I want to design a new Board with this puppy I'm searching for preferably chines power solution chips for this FPGA, do you recommend any thing special or good?
I was searching LCSC and find this part JW5068A it's from JoulWatt  and can deliver 8A and it's only 0.5$, do we have some parts from a chinese manufacturer with multiple outputs or higher current with similar prices? also in this JW5068A  data sheet there is no info regarding the L and other passives calculations.

[OwO]

Above 10A you probably want to look into designing your own multiphase buck converter using a CPLD, gate drivers, and discrete FETs. It's not going to be any more expensive than using an overpriced all-in-one solution and potentially performs better (if you did your design work well).

[ali_asadzadeh]

Thanks, the space is limited and I do not have time for Designing it right now, I'm looking into cheap solutions,
Also I have found this part
RT6242A, it's a 12A puppy, I have no price info, But maybe it's under 1$

[tszaboo]

Thanks, the space is limited and I do not have time for Designing it right now, I'm looking into cheap solutions,
Also I have found this part
RT6242A, it's a 12A puppy, I have no price info, But maybe it's under 1$

Are you that desperate to design with a 1 dollar chip for a 800 dollar digikey price FPGA? What if you blow up one chip, because poorly documented transients on that JW5068A or just having the wrong capacitor in the loop filter? Are we really having this race to the bottom? Instead of placing a 5 dollar module from TI on it, and concentrating the engineering where it actually matters.

[OwO]

xc7k325t is around $100 on LCSC and cheaper on the market. TI power management ICs are known to be poorly designed and have an above average tendency to blow up: https://www.eevblog.com/forum/projects/psa-do-not-use-the-tps61099-boost-reg-in-your-designs/

[asmi]

That "puppy" can consume up to 12 Amps of power on the Vccint rail, and that rail is also required to be extremely precise (3%) and extremely low ripple (<10 mVpp over 0-20 MHz). No way your cheap Chinese crap is going to deliver this. Nor do you unless you have an extensive experience in DC-DC converter designs. I will just say one word - thermals, that thing is almost never properly designed in by typical wannabe designers.
Also K325T requires paid Vivado license to build designs - do you have that? Or you're going to do it the usual Chinese way - i.e. use pirated version?

[ali_asadzadeh]

Guys thanks for sharing,

Also K325T requires paid Vivado license to build designs - do you have that? Or you're going to do it the usual Chinese way - i.e. use pirated version

I have the license , Please do not worry.

Are you that desperate to design with a 1 dollar chip for a 800 dollar digikey price FPGA? What if you blow up one chip, because poorly documented transients on that JW5068A or just having the wrong capacitor in the loop filter? Are we really having this race to the bottom? Instead of placing a 5 dollar module from TI on it, and concentrating the engineering where it actually matters.

This project is for mass production and we can get it under 100$ from china, so the winner is the one that can do the job @ lower price.

[asmi]

Above 10A you probably want to look into designing your own multiphase buck converter using a CPLD, gate drivers, and discrete FETs. It's not going to be any more expensive than using an overpriced all-in-one solution and potentially performs better (if you did your design work well).

It won't be unless you have a lot of experience in that area. Infact it will probably work much better as a broadband jammer than as a DC-DC converter
So, yeah - do yourself a favor and get one pre-designed by people who know what they are doing.

[OwO]

I've designed current mode DC-DC converters before, it's really not that hard but yes you need to know what you are doing. EMI is my expertise and I have no issues designing circuits with 100dB isolation on tiny 4 layer boards. I also dispute that the designers at TI really know what they are doing since they can not even get a power supervisor working correctly, seem to have trouble designing load switches that don't randomly blow up, and battery management ICs that don't get into a state where it drains the battery.

[asmi]

EMI is my expertise and I have no issues designing circuits with 100dB isolation on tiny 4 layer boards.

We've all seen your "expertise in EMI" on that Zynq board which would radiate like there is no tomorrow Nobody who claims to care about EMI would ever place high-speed traces on external layers.

I also dispute that the designers at TI really know what they are doing since they can not even get a power supervisor working correctly, seem to have trouble designing load switches that don't randomly blow up, and battery management ICs that don't get into a state where it drains the battery.

I use their power parts almost exclusively for years and never has a single issue with them. So I have my doubts that you will ever do a better job at this than they would, especially given what I said above.

[asmi]

Every cheap consumer device (which has to pass the most strict class B EMI) is designed with high speed signals on outer layers. Many motherboard running DDR3 signal at up to 4266MT/s (2133MHz) are only 4L, with 2 center power and ground layers and 2 outer layers, running 128/144 bits of 2133MHz signal.

Do you mean the ones which are certified only when working inside a Faraday cage (a.k.a. computer case)?

[daqq]

Analog has a few very compact modules with the coil included. While they are pricier per chip, you just add a few capacitors and you are done. You save on space and the inductor and some passives.

[OwO]

Those DDR traces are on the same board as a AD9363 transceiver. If there was a noise problem I would know by now. Open up any WiFi router and you will see DDR traces on outer layers. Microstrips on 0.1mm prepreg doesn't radiate much *if* you actually keep ground planes solid and well stitched at layer transitions.

If you do decide to go with an off the shelf module stick with LTC/ADI, they actually have analog design expertise which seems to be absent at TI these days.

[ali_asadzadeh]

Are you that desperate to design with a 1 dollar chip for a 800 dollar digikey price FPGA? What if you blow up one chip, because poorly documented transients on that JW5068A or just having the wrong capacitor in the loop filter? Are we really having this race to the bottom? Instead of placing a 5 dollar module from TI on it, and concentrating the engineering where it actually matters.

If some company can make a chip, they have at least spent a lot on resources, like time and money! EEVBLOG members told me in this thread that making even samples of chips cost a lot
https://www.eevblog.com/forum/projects/fabrication-your-own-chips/

Laptops and other high volume dirt cheap devices use something called a DrMOS, with gate drivers, current sensors and high/low side FETs packaged together. You can buy some AO Semiconductor ones for a few tens of cents per 35A phase block.

Do you have any part numbers, It seems very interesting!

[ali_asadzadeh]

Visit AO's website, and find whatever the part tat you can buy on LCSC and fits your requirements.

you mean https://ao.com/? it's a washing machine website, do you have their website address.
Thanks

[ali_asadzadeh]

http://www.aosmd.com/products/power-ics/drmos

Thanks for the info.

DO they need a controller too? I checked some parts data sheet, and They only contain MOSFET and driver, what do you suggest for the controller?

[TimCambridge]

xc7k325t is around $100 on LCSC and cheaper on the market.

LCSC prices for Xilinx parts are a mystery to me. The XC6SLX9-2TQG144C (a terrible package) is available on LCSC at around $5 (31 in stock), it's $17 on Digikey.

Is that because sourcing this sort of component via LCSC is a bit of a gamble on availability?

[ali_asadzadeh]

I got price info on RT6242BHGQUF from it's company, it's around 0.35USD and it can deliver 12A, I need around 15A for the Vcore of the FPGA, Can I use two of this RT6242BHGQUF  and connect half of the Core pines to one IC and the next half to the another one!

[ali_asadzadeh]

LCSC prices for Xilinx parts are a mystery to me. The XC6SLX9-2TQG144C (a terrible package) is available on LCSC at around $5 (31 in stock), it's $17 on Digikey.

Is that because sourcing this sort of component via LCSC is a bit of a gamble on availability?

you should not buy from Digikey then!

[OwO]

Before designing in any part always check taobao. If there are many sellers selling it it's usually safe even if it's long discontinued. I designed the cmy210 RF mixer into a new design when it was already discontinued at all major distributors, but right now many years later I can still get it on taobao below 1CNY/pc.

No you can not feed different Vccint pins with separate buck converters. The pins are all internally shorted in the FPGA package.
RT6242 and JW5068A are only good up to 6A. The efficiency is 90% and you simply can not dissipate more than about 0.6W in that package.

[OwO]

Have you designed Artix/Kintex boards before? If not, I highly recommend practicing with a Artix XC7A100T. The power distribution layout design is going to be the hard part for most people. See also https://www.eevblog.com/forum/repair/how-to-test-salvageable-xilinx-ultrascale-board-from-ebay/

I will be playing with these soon (please don't go and buy a bunch of them and drive the price up):

[ali_asadzadeh]

Have you designed Artix/Kintex boards before? If not, I highly recommend practicing with a Artix XC7A100T. The power distribution layout design is going to be the hard part for most people. See also https://www.eevblog.com/forum/repair/how-to-test-salvageable-xilinx-ultrascale-board-from-ebay/

I will be playing with these soon (please don't go and buy a bunch of them and drive the price up):

Yes, I have done it before for ARTIX (XC7A100T) and I have used a TI part LMZ31710, So for this Kinetis, I want to use low priced parts.

[ali_asadzadeh]

Unfortunately, Taobao does not open to other people, it needs registration and needs a cell phone for registration, which I do not have a chinese phone number

[tszaboo]

xc7k325t is around $100 on LCSC and cheaper on the market.

LCSC prices for Xilinx parts are a mystery to me. The XC6SLX9-2TQG144C (a terrible package) is available on LCSC at around $5 (31 in stock), it's $17 on Digikey.

Is that because sourcing this sort of component via LCSC is a bit of a gamble on availability?

Or they bought a partial reel remaining from someone, and have 0 guarantee to have the parts again.
Or they are selling it below their cost, because they want to get rid of a stock.
Or they found a reel of it in a corner of a warehouse with unknown origin and want to sell it.
You dont build a business on LCSC. Or even digikey for that matter.

[TimCambridge]

xc7k325t is around $100 on LCSC and cheaper on the market.

LCSC prices for Xilinx parts are a mystery to me. The XC6SLX9-2TQG144C (a terrible package) is available on LCSC at around $5 (31 in stock), it's $17 on Digikey. Is that because sourcing this sort of component via LCSC is a bit of a gamble on availability?

Or they bought a partial reel remaining from someone, and have 0 guarantee to have the parts again.
Or they are selling it below their cost, because they want to get rid of a stock.
Or they found a reel of it in a corner of a warehouse with unknown origin and want to sell it.
You dont build a business on LCSC. Or even digikey for that matter.

Digikey gives you a starting point, then you negotiate - a skill that we all have

I've just looked up the LCSC prices for the old Cypress FX2 ( CY7C68013A, 8051 based! ). There's a price spread of 4:1 between the package options, and all cheaper than list price ! Has this part been cloned?

More seriously, is there a broker service that navigates taobao for foreigners?