LDO Powers Automotive Modules

STMicroelectronics’ LDO40L 400-mA low-dropout (LDO) linear regulator delivers quiet and efficient power for always-on automotive modules and noise-sensitive loads. Specifying a 45-µA quiescent current, the AEC-Q100 qualified LDO40L reduces the demand on vehicle batteries to run loads such as body and interior functions that are active when the ignition is off. In addition, the device can be disabled to achieve a shutdown current of 1µA.


The internal circuity operates from an input voltage as low as 3.5V and combined with the low dropout voltage of 36 mV at 100 mA load, or 140 mV at full load, they enable the LDO40L to maintain power to the load as the input dips during cold cranking. Output noise is 20 µV, power-supply rejection ratio (PSRR) is 70d B at 1 kHz, and protection features include current limit and thermal shutdown.

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Device variants give a choice of fixed 3V, 3.3V, 5V, or 8.5V output voltage, regulated within ±3% including line, load and temperature variation. Only two capacitors are needed to complete the application circuit. An adjustable-output version is also available, which allows designers to set a desired output voltage down to 2.5V minimum using an external resistor divider. All versions are housed in a 3 mm x 3 mm DFN6 package with wettable flanks, which is smaller than the DPAK outline of typical competing devices yet maintains high thermal performance and excellent reliability in relation to heatsink size.


The LDO40L series is in full production now, priced from $0.62 each/1,000. For more info, checkout the datasheet.

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