LMZ22010: Design as programmable via pot or DAC

randall veitch

Prodigy 180 points

Part Number: LMZ22010
Other Parts Discussed in Thread: TPSM84A22, TPSM84A21, LM317, LMZ14203H, PTN78020W

Is this LMZ22010 module a fair candidate for a programmable supply via pot, I2C pot, DAC, etc.?

over 6 years ago

0 Michael Daimer over 6 years ago

TI__Intellectual 1155 points

Hi Randall,

what is your application, where you want to use LMZ22010?
In principle there is a way to control the output voltage with a DAC or something similar. It depends on your application, output voltage, etc...

Have a look on TPSM84A21 or TPSM84A22. These two devices could be interesting for what you have in mind.

Best regards,
Michael

0 randall veitch over 6 years ago in reply to Michael Daimer

Prodigy 180 points

Thanks for the reply Michael.

I need to design a supply for a programmable output up to 12VDC. The LMZ series seems a likely candidate for this.

TPSM series does not seem to accommodate the output range I need.

I just wanted to know if there were any negatives to using the LMZ modules in this way.

(These modules would dissipate a lot less heat than a comparable, linear LM317 type application)

Thanks,

Randy

0 Michael Daimer over 6 years ago in reply to randall veitch

TI__Intellectual 1155 points

Hi Randall,

there should not be a problem with the device, as long as specs from the datasheet are not violated.
E.g. voltage on FB pin too high etc...

What is your favorite method in programing the output voltage?
Perhaps we have a similar solution with a similar board already as a reference design.

Best regards,
Michael

0 randall veitch over 6 years ago in reply to Michael Daimer

Prodigy 180 points

Hi Michael,
I have not spent any time with the data sheet yet but I would probably be inclined to use a digital pot for Rfbb to ground. It would be great if there were an existing reference design available....for any method.

Randy

0 Michael Daimer over 6 years ago in reply to randall veitch

TI__Intellectual 1155 points

Hi Randy,

there is a reference design in work that uses a external tunable voltage source on the Rfbb to GND, just like you mentioned.
So it is possible to tune the voltage like that. Your idea goes in the right direction.

I don't know exactly, when the board, testing and the documentation is finished, but I will reach out to you as soon as I know more.

Best regards,
Michael

0 Michael Daimer over 6 years ago in reply to randall veitch

TI__Intellectual 1155 points

Hi Randy,

there is one comment I have to add.
I started some calculations for you and then I recognized that the maximum output voltage for the LMZ22010 is only 6V. So your desired 12VDC is not possible. if you also need 10A output current.

PTN78020W could fit your requirements. For less output current try the LMZ14203H, which is a 3A device.

-Michael

0 randall veitch over 6 years ago in reply to Michael Daimer

Prodigy 180 points

Thanks Michael,

The PTN78020W looks like a winner for my apps.....

I took a look at the data sheet but could not locate one particular pc of info. There is a PTN78020WAD and an PTN78020WAH available; both through-hole pkgs,

However, I cannot find a definition or the difference between the WAD and WAH suffix.

regards,

Randy

0 J Arrigo over 6 years ago in reply to randall veitch

TI__Mastermind 28020 points

Both WAH and WAD are identical.

The device was originally released as a WAH suffix, before the Pb-free initiative. The device was converted to Pb-free in ~2005 and at that time we released the WAD suffix. Since then, the WAH was also converted to Pb-free. So now both devices are identical. Both devices will continue to be supported.

0 randall veitch over 6 years ago in reply to J Arrigo

Prodigy 180 points

Thank you for the info.
Regards,
Randy

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LMZ22010: Design as programmable via pot or DAC