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TPS62080A Snooze Mode

Ignacio Linares
Expert 1655 points
Other Parts Discussed in Thread: TPS62080A, TPS62740

I have customer having the issue below.  I need some suggestions on how to resolve this issue:

I have been chasing down a 150mV 16KHZ ripple on my 3.0V supply. The supply is sourced by a TPS62080A.  My load is around 100mA. I found the problem was the snooze mode, disabling that dropped the ripple to <10mV. My question is at 100mA load, why  is snooze mode kicking in? Or is that noise expected at any load?

Mode pin is pulled high when I see the problem. My understanding is by enabling it, it will only snooze when the load is light, which it is not right now. The load is light when the CPU goes to sleep (it currently is not in sleep) and so I wanted to have the snooze mode enabled because eventually the CPU will spend 99% of its time in sleep, so wanted better efficiency at light loads.

  • 0
    TI__Genius 13700 points

    Hello Iggy,

    Looking through the datasheet for the TPS62080A on Pg. 13 of the datasheet in one of the sections that discusses "Snooze Mode" form my interpretation it is irrespective of the load and entirely dependent on the MODE pin.

    Do they have a schematic of the device? I would think that having a pull up resistor on the MODE pin so that when the CPU is sleeping that pin can float high but when the CPU is active having it actively pull the pin down causing the TPS62080A to leave sleep mode. This operation is described at the bottom of the excerpt below.

  • 0 in reply to Ryan May
    TI__Guru*** 144230 points

    Yes, Ryan is correct.  You need to disable snooze mode by pulling MODE low.  Please limit the load current in snooze mode to less than 2mA per the D/S.

    A brand new, more efficient, though lower power, device is the TPS62740.