TLV840: Timing Clarification

Abigail Leonardi

Part Number: TLV840

Tool/software:

Hi,

My customer is using the TLV840. The timing in question is tD on the datasheet and is the delay from MR to Reset release. If we are using a 1uF, 10% capacitor connected to pin 5 (CT) and the datasheet indicates this has a tD of 619 mS typical, or 680mS with 1.1uF.

However, we're seeing about 700mS delay instead of 619ms. Are there min and max conditions for the tD that I should expect? The reason for asking is that the in-circuit test needs to have bounds on the timing.

2 months ago

0 Jesse Villanueva 2 months ago

TI__Mastermind 18980 points

Hi Abigail,

What type of capacitor are you using when testing? Also, what is the ambient temperature of the board?

Jesse

0 Abigail Leonardi 2 months ago in reply to Jesse Villanueva

TI__Expert 3550 points

The capacitor is a MLCC (Kemet C0603C105K4RACTU for example) and this has been at room temperature, around 22 deg C.

0 Jesse Villanueva 2 months ago in reply to Abigail Leonardi

TI__Mastermind 18980 points

Hi Abigail,

Are you able to share the schematic that you are using?

Jesse

0 Abigail Leonardi 2 months ago in reply to Jesse Villanueva

TI__Expert 3550 points

I just sent over a message to you, but is there any other information we can send over with the ask for schematic?

For example, if we are able to confirm if there are min and max conditions for the tD that they should expect?

+1 Jesse Villanueva 2 months ago in reply to Abigail Leonardi

TI__Mastermind 18980 points

Hi Abaigail,

We can calculate the Min and Max for their current setup.

taking the values to account, we have the min/max values below.

typ log	0.29
min log	0.36
max log	0.26
cap (uf)	1
typ	0.000001
min	0.0000009
max	0.0000011

Time (s)
typ	0.6189872
min	0.3218701
max	0.8002117

I have also reviewed their schematic and everything looks good there as well.

Jesse

0 Abigail Leonardi 2 months ago in reply to Jesse Villanueva

TI__Expert 3550 points

Thanks Jesse!

0 Abigail Leonardi 2 months ago in reply to Abigail Leonardi

TI__Expert 3550 points

The customer asked for some clarification as to where the min and max log values of 0.36 and 0.26 come from. Are those from the TLV840 or from the circuit/capacitor?

+1 Jesse Villanueva 2 months ago in reply to Abigail Leonardi

TI__Mastermind 18980 points

Hi Abigail,

That would be from the internal current source that is charging the capacitor.

Jesse

Power management

Power management forum

TLV840: Timing Clarification