Tiny LDO Extends Battery Life In Portables


Low drop out (LDO) regulators are widely used in portable electronic gadgets due to the stringent demands for long battery life and small size in these applicatons. Examples include smartphones and tablets, smart watches, audio or media devices, wearables, etc.

However, designers generally face a trade-off between parameters like quiescent current, output power, dynamic response, and package size.

To give designers extra freedom, STMicroelectronics has announced a new low-dropout (LDO) voltage regulator that offers a right combination of attributes, making it ideal for use in battery-powered consumer products like smartphones and tablets, smart watches, audio or media devices, and wearables.


As claimed by ST, “the STLQ020 draws just 300nA quiescent current (Iq), and is capable of supplying up to 200mA to the load with excellent regulation, power-supply rejection (PSRR), and transient response. The chip is available in a choice of compact packages as small as a 0.8mm x 0.8mm flip-chip.”

The chip works with an input voltage ranging from 2 V to 5.5 V. The typical dropout voltage at the maximum load is 160 mV.

ST said that the device utilizes an adaptive biasing circuit and low-power design to be able to provide fast transient response and good PSRR performance and stable output.

The ultra-low quiescent current, which is just 0.3 μA at no load, extends battery-life of applications requiring very long standby time. These include IoT endpoints such as smart meters and wireless sensors, healthcare devices like wearable monitors, and industrial applications such as factory automation or sensor networking.

Enable pin puts the STLQ020 in shutdown mode, reducing total current consumption to 1 nA. This helps to extend the interval between coin-cell replacements in low-duty-cycle applications like remote sensors.

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A dropout voltage as low as 160mV (typical) at maximum load allows longer equipment runtimes as the battery discharges.

An input voltage range of 2.0V-5.5V allows the STLQ020 to be powered directly from a suitable battery voltage (VBAT) or logic rail. The output voltage can be set between 0.8V and 4.5V, with either fixed-output or adjustable-output versions available. The fixed output voltages are selectable in 50mV increments.

The STLQ020 is in production now, and available as a 2mm x 2mm DFN6, 0.8mm x 0.8mm flip-chip4, or 2.1mm x 2.0mm SOT323-5L, priced from $0.168 for orders of 1000 pieces.

ST has also developed a quad-LDO evaluation board (STEVAL-LDO001V1) based on STLQ020 and 3 other low-dropout (LDO) voltage regulators, which can be ordered for $9.68.

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