TPS3808: Is there any better reset delay time accuracy solution than TPS3808?

Shinya Sawamoto

Part Number: TPS3808
Other Parts Discussed in Thread: TPS3890

Hello team,

I'm looking for a solution which has better reset delay time accuracy than TPS3808.
As described on the datasheet, TPS3808 has 40% accuracy, but I need to find <30% accuracy due to the specific application requirement.
The typical reset delay time is 800msec.
Is there any good idea to solve it?

Thanks in advance.
Shinya Sawamoto
TI Japan East area FAE

over 6 years ago

0 Michael_DeSando over 6 years ago

TI__Genius 12630 points

Shinya,

Do you know the temperature range and VDD supply voltage for your application? This will help me find a good fit for you.

-Michael

0 Shinya Sawamoto over 6 years ago in reply to Michael_DeSando

TI__Expert 5260 points

Thanks for your reply, Michael.
The temperature range is -10 to 60C.
The VDD is 3.3V.

Regards,
Shinya Sawamoto

0 Shinya Sawamoto over 6 years ago in reply to Shinya Sawamoto

TI__Expert 5260 points

No available solution..?

Regards,
Shinya Sawamoto

0 Antony Pierre Carvajales over 6 years ago in reply to Shinya Sawamoto

TI__Intellectual 1900 points

Hi Shinya,

Please take a look at the TPS3890, which has a tighter accuracy on the CT pin charge current and CT pin comparator threshold voltage

0 Shinya Sawamoto over 6 years ago in reply to Antony Pierre Carvajales

TI__Expert 5260 points

Hi Antony,
Thank you for your recommendation.
I reviewed it and found it can't satisfy the target <30% from my calculation.
If you have any other option or advice, it will very appreciated.

min typ max
C 0.612 0.68 0.748 uF (with 10%)
V 1.17 1.23 1.29 V (from datasheet)
I 0.9 1.15 1.35 uA (from datasheet)

T=CV/I
Target T 800 ms
min typ max
Calculated 530.4 727.3 1072.1 ms
Accuracy -27.1 0 47.4 %

Regards,
Shinya Sawamoto

0 Shinya Sawamoto over 6 years ago in reply to Shinya Sawamoto

TI__Expert 5260 points

Hello team,

Do you have any other good proposal?
If not, I'll give up this socket and will close this discussion.

Regards,
Shinya Sawamoto

0 Antony Pierre Carvajales over 6 years ago in reply to Shinya Sawamoto

TI__Intellectual 1900 points

Hi Shinya,

The TPS3890 is the closest solution. I did the calculation using 800ms as the nominal value and obtained +-34% which is closer to the 30% target.

If the reset accuracy has to be less than >30% they should consider using a 5% tolerance capacitor

www.digikey.com/.../60

TPS3890
MIN	Nominal	MAX
530.4	800	1072.1
-34%		34%

Ideal delay accuracy of 30%
MIN	Nominal	MAX
560	800	1040
-0.3		0.3

Regards,

Antony

0 Shinya Sawamoto over 6 years ago in reply to Antony Pierre Carvajales

TI__Expert 5260 points

Thanks Antony,
I understood TPS3890 is the best solution. I'll contact you by email when I have further question.

Regards,
Shinya Sawamoto

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TPS3808: Is there any better reset delay time accuracy solution than TPS3808?