Which 1.8V Ultra-Low Quiescent Current LDO for battery prj.

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Hi all,

Which 1.8V Ultra low quiescent current LDO for battery project. Battery voltage is quite high (12V-15V) AcidLed Battery and will be charged with 20W sollar panel.

I am adding my board to existing power source I can't use 6V battery or AA batteries.

I wish use AVR 8bit MCU on 1.8V and 1Mhz (verry low power consumption)
MCU will drain in Idle or PowerDown mode few uA but I can't find suitable LDO with SOIC/TO package which has ultra low quiescent Current and so big Vin.

Thank's for any suggestions.

I dont wan't use hundry LDO which will drain more then MCU.

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I needed something like this last project. I believe we looked at the MCP1703. If I recall correctly it has 5uA with no load out. Input to 16V. There must be more out there like this.

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Also found an AS1360-18-T at digikey that claims 3uA quiescent. However, it requires an electrolytic or tantalum capacitor. I believe the MCP1703 is happy with ceramic. YMMV. Good luck!

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LT3007 Series - 3μA IQ, 20mA, 45V Low Dropout Fault Tolerant Linear Regulators (Linear Technology)
Its press release was April 2 2013.

"Dare to be naïve." - Buckminster Fuller

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I love LT. Missed this one. They use ceramic also it seems.

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MAQ5283: 120VIN, 150mA, Ultra-Low IQ, High-PSRR Linear Regulator (Micrel)
has an automotive rating, much greater ripple rejection than LT3007, but does not have LT3007's reverse capabilities.

"Dare to be naïve." - Buckminster Fuller

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I thought LDO meant Low DropOut meaning it can run on an input voltage very close to the output voltage. In your case you dont need an LDO in my opinion.

Also be sure you know where most power is dissipated in your schematic.
When your uP dissipates eg 10uA @ 1V8 (18uW), even a perfect voltage regulator with 0uA quiescent current connected to 12V input would dissipate 10uA * (12V-1V8) is 102uW.
To solve this, you'd probably be better off with a step-down converter.

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or MIC5205-3.3YM5 TR

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Yes, LDO mean "Low drop Out". This usually mean that the design allows the input to be no more than a few hundred mV above the output. Sometimes down to 50mV or less.

You PAY for this capability. One cost is capacitors. Some places, like Linear Tech, have no "normal" regulators - it is LDO or nothing. But, for really low quiescent current, it is usually necessary to go LDO. Many companies do not make LDOs with very high input voltages (though a few like LT do).

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net