Low quiescent linear Voltage Regulator


For a battery powered circuit, I need a VERY low quiescent current voltage regulator.
Input voltage is 20V lithium battery, output voltage is 5V (or 3.3V, precision not necessary) for a microcontroller circuit.
The max current, when uC is working, should be at least 50 mA.
The quiescent current of the regulator itself (when uC is in sleep mode) should be no more than 10uA.
On the battery terminals, there are transients of 40V to be expected.
Any ideas?
No automotive application, but sort of power tool. The uC, when in "sleep mode", waits for "years" until it detects a "keypressed" by the user, before starting the engine. The whole appliance is very cost sensitive, so the regulator should be in a price range of 0.1..0.2 USD @ 10K pa. If anyone has a cheap 20uA solution: welcome.

Best Answer

The TPS7A6601 has 12uA typical (20uA max) Iq, and can withstand 45V for 200ms. Pretty close.

Or make a high dropout/high voltage linear pre-regulator using a MOSFET voltage follower and one of the many low-Iq LDO CMOS regulators that can't handle high input voltage.