In applications that need to run from a small battery cell for longer periods,
you want to make the application average power consumption as low as possible.
These applications will often run in sleep mode most of the time,
and are only active for short periods.
To minimize the power consumption in sleep mode,
you need to selects parts with very low quiescent current,
and this is where Richtek low Iq LDOs are really suitable.
LDO Iq or LDO quiescent current is the current
that is consumed by the IC internal feedback control and drive circuits.
It is normally measured by measuring the current
that flows out of the LDO ground pin.
The quiescent current of standard LDOs
ranges from 25µA up to 1mA.
In applications that need to run from batteries,
this can be too high,
because even if the LDO output has zero load current,
the battery is slowly drained by the LDO quiescent current.
The Richtek Low Iq LDO portfolio
contains LDOs with quiescent currents down to 1µA,
which extends battery life considerably.
Here is a typical battery powered application
where a micro controller periodically sends out data via an RF link.
In order to ensure long battery life,
the micro controller is in sleep mode most of the time,
consuming only 10µA.
When the micro controller and RF section become active,
the load momentarily goes up from 10µA to 25mA.
The Low Iq LDO RT9063 provides a stable 2.8V supply to the micro controller,
and the LDO ground current stays relatively constant at 1µA in the low load range,
there by prolonging battery life.
But at higher load currents, the ground current increases.
This is done to improve the dynamic behavior of the LDO
when a sudden high load is encountered,
the internal control circuit uses more energy to regulate the output voltage.
To show this be havior,
here is a transient measurement with a fast load step from 10µA to 25mA
due to the LDO's use of dynamic quiescent current,
the LDO can react quickly to the load step.
The LDO output does not drop more than 1.2%,
ensuring stable micro controller operation.
The Richtek LDO portfolio contains many low Iq parts.
In different packages, with or without an Enable pin
and input voltage ranging from 6V up to 36V.
For more information, please click the link at the left side,
or visit the Richtek website at www.richtek.com