LM74700D-Q1: RPP only

I found Lm74801-Q1 support RCP only mode. Is this the lowest solution from TI to support 48V with ISO21780 (abs max >70V)?

To achieve that, do we just need to leave C-pin floating? Would you please let me know full recommended circuit on this usecase?

regards,

Hi Yuto,

What is the max voltage that you are looking for?

Regards,

Shiven Dhir

Hi Shiven,

As I mentioned at first, to support ISO21780(70V/40ms survive) is needed.

Q1: Can we use LM74700D-Q1 for only RPP without RCB?

Q2: Can we use LM7450x for ISO21780 required application?

Q3: I found LM74801-Q1 supports the all requirements. Is this the lowest cost solution from TI?

Q4: Can you share me the full schematics to achieve RPP only with LM74801-Q1? Do we need just to leave float the C-pin?

Best regards,
Yuto Kitamura

Hi Yuto,

1. LM74700D cannot be used for RPP only. This means RCB cannot be disabled.

2/3. LM74500 has similar architecture as LM74700D and hence the abs-max of 70V can be sustained by LM74500 as well.

4. I will get back to you with this.

Regards,

Shiven Dhir

HI Dhir,

Thanks for comment.

1. Clear, thank you.

2/3. I cannot find such information on datasheet. Can you tell me where I can find it? Or do we need system solution like external TVS? or will the datasheet be updated to SOURCE to GND 70V_abs max?

4. Thanks, please check and update to me.

best regards,
Yuto

Hi Yuto,

2/3. There isnt a change planned in datasheet.

4. Yes, you just need to keep the "C" pin floating.

Regards,

Shiven Dhir

Hi Shiven,

Thanks.

2/3. Then how can we understand LM74500-Q1 can support 70V? Please let me know. If not, LM74801-Q1 will be the solution. 

4. Clear.

Warm regards,
Yuto Kitamura