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Part Number: TPS735
I use TPS73501DRVR in my design, I want to the output delay when power on,the delay time is 20~30ms.
The input power is 5V, the output is 3.3V,I add the RC on the EN of TPS73501DRVR ,R=100k, C=1uF.
Since the VEN(HI)=1.2V, The delay time is calculated as follows:
Is the delay time calculation formula correct when power on?
Is there any other delay time need to add when power on?
Could you help to review the SCH as attachment, please give your comments,
This would not be reliable as the 1.2V threshold is the minimum in which we guarantee that the device will be enabled. The datasheet shows the following:
So above, 1.2V, we say it will definitely be ON, and below 0.4V it is definiely OFF. Betwen these two thresholds, it could be in either state.
Using a device like the TPS3840 would be a way to precisely control the enable delay timing.
Does this answer your question?
John Cummings 蔣康明Texas Instruments 德洲儀器Johncummings@ti.com
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In reply to JCHK:
Thank you for your support.
I will add precisely control the enable delay timing in my design.
I want to know the delay time from EN(>1.2) to the output rise up to 3.3V, I can't find the delay time on the datasheet?
Could you help to calculate this delay time ?Please refer to the SCH.
Which factors will affect this delay time?Is the delay time stable when I power on and power off repeately？
In reply to kevin p:
We do not test this in production, but we do show a typical rise tine from EN going high to VOUT being in regualtion:
so you are lookng at ~60us from Enable going high. This chart also highlight how the quickstart circuit help to maintain the statup time with different output capacitors.
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