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TPS54061: TPS54061 - Iq - how to interpret it

Sunset
Genius 13395 points
Part Number: TPS54061
Other Parts Discussed in Thread: LM5165,

Hello Team,

in the datasheet of the TPS54061  is written that Iq is 90uA (typ) under the following condition: Operating – Non switching.

What does it means Operating but not switching?

the datasheet describes:

The TPS54061 has a default startup voltage of approximately 4.5 V. The EN pin has an internal pullup current
source that can be used to adjust the input voltage UVLO threshold with two external resistors. In addition, the
pullup current provides a default condition. When the EN pin is floating the device will operate. The operating
current is 90 μA when not switching and under no load. When the device is disabled, the supply current is 1.4
μA.

what is the use case of being operating but not switching rather than being disabled?

The only thing that comes in my mind is that I have an high side switch following the DC-DC converter and it disables the circuitry following it.

I find that the way Iq is specified by the LM5165 is more comprehensive, simply from the description and not from the scenarios that it covers.

For consistency on the LM5165 I would have used "no load" and "with load" but also active let me think about loading the device.

  • The TPS54061 Iq is the one that the LM5165 specifies as Iq sleep?
  • What is the TPS54061 Iq typ. while the device output is loaded?

Having less specified parameters may let the TPS54061 being more cost efficient than the LM5165, but the description may be misleading.

thanks,

SunSet

  • 0
    TI__Mastermind 25590 points

    SunSet,

    We usually spec non-switching Iq when the part has frequency foldback / pulse skipping at light loads. This is so that the reader has an idea of the lower-bound of operating currents when the part switches at an extremely reduced frequency from nominal.

    • You are correct, "TPS54061 Iq Operating - Non switching" is the same as "LM5165 Iq_SLEEP"
    • The TPS54061EVM-142 Iq is as follows (with 3.3VOUT, 400kHz set (with pulse skipping), no load):

    VIN Iq
    12V 243uA
    24V 251uA
    48V 336uA

    -Sam

  • 0 in reply to Samuel Jaffe
    TI__Genius 13395 points

    thanks for the info.

    SunSet