I have a few step-up converter modules such as
supposedly based on the MT3608 IC:
There seem to be clones/identical ICs available, such as SX1308:
- http://www.nmj.sumomo.ne.jp/suz-avr/PMIC/SX1308-Suosemi.pdf (datasheet virtually identical to the one above)
I am aiming for a battery operated (two alkaline cells, so 3..2 V input, 3.3 V output) circuit with an "off" current of around 1 µA. According to the datasheet, the EN pin set to 0 V (GND) should achieve exactly this - however, depending on input voltage and feedback resistor divider (= output voltage) setting, this varies between 0.1 to 0.2 mA, which corresponds to the quiescent current for the PFM mode of operation.
I'm testing at Vin=4.6V, Vout=10V, no load. Input current is approx. 1 mA when EN at Vin. With EN at 0V, Vout corresponds to Vin.
From that it seems the IC does go into shutdown, but simply fails to fulfill the specs?
Of course, the feedback voltage divider causes about 50uA at that input voltage, regardless of the IC's consumption, so it's probably not suitable anyway.