I have two questions about the TPS65251:
1) What is the ramp up and ramp down time on the TPS65251 power outputs ( or definable min and max )? I see that I can set the soft-start time in the datasheet page 15 but would like to know the usable min and max values in practice?
2) What is the state of the V3V pin 29, and the V7V pin 28 when I have a 12V input and EN 1-3 are asserted LOW? Can these be used to power a small load of 5mA? THis would be a neat "little trick" for me to power a very small load if possible.
Thank you,
Bryan Busacco
Regarding the 2nd Question:
From the data sheet - "The device has two built-in LDO regulators. During a standby mode, the 3.3-V LDO and the 6.5-V LDO can be
used to drive MCU and other active loads. By this, the system is able to turn off the three buck converters and
improve the standby efficiency."
A 5mA load is fine. I checked the outputs real quick and found that the LDOs will drop by 5% around 45mA of load. We don't reccomend loading exceed 10mA.
Im currently looking into the first question.
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Greg Watkins
Analog Applications
Soft start has a maximum reccomended time of 5ms.
LDO pins have a maximum reccomended loading of 10mA