This article will help the automotive designer on limiting the inactive or idle current on battery powered equipment has to remain working while the automobile is turned off. In particular is the digital circuits that need low core voltages and quiescent power that has to keep running.

By using the MAX16999, the application data can show how it can give the needed low quiescent power for very low voltages to keep the electronic circuit systems alive. This micro power linear regulator has some of the features that will answer these low voltage or micro voltage requirements. Devices that need sustained battery power like cell phones, information and entertainment consoles or personal navigation devices on the car should have the proper amount of power to keep their needed functions alive; this is a big challenge particularly for automobile designers.

Integrated digital circuits have low core voltages that need two kinds of power rails required in an application namely, interface and core rails. So it is not sufficient to make available one low quiescent interface supply rail to keep the system alive. An added low quiescent power is also needed by the microprocessor core or a RAM chip is required also.

This is what the MAX16999 can provide, the additional rail that can supply output voltages below 1,2V @ 12uA which is necessary for very low loads. It operates with an input voltage or 2.5 to 5.5V and provides stable load current not greater than 100mA. The voltage output is preset to .5 to 3.3V in 100mV linear steps. The dynamic low release drain restore output continues at this state for a programmable break delay by using an external capacitor linked to the CRES, after the output voltage attains regulation. This characteristic eases up power supply sequencing.

Electrical devices that have need of a load current with core rail to exceed 100mA during operation. On this scenario, the output of the MAX16999's and reset stage are calibrated to be on high-impedance state when the device is put out of action.

http://www.maxim-ic.com/appnotes.cfm/an_pk/4251