From Maxim Integrated Products, the MAX8569A and MAX8569B are step-up dc-dc converters with a built-in synchronous rectifier and up to 95% efficiency. The converters consume only 7 µA of quiescent supply current to extend battery life in handheld battery-operated applications, such as glucose meters and digital cameras.
The devices have a 1.5-V to 5.5-V input voltage range and can deliver up to 200 mA at 3.3 V with a 2-V input supply. When in shutdown, the output voltage connects to the input voltage through a low-resistance switch (and not a full drop of a diode), allowing the main battery to be used for backing up the system. This feature eliminates the need for a separate backup battery, saving board space and system cost.
The MAX8569A has an adjustable 2-V to 5.5-V output. The MAX8569B is available in 3.0-V and 3.3-V fixed output voltages, and has a reset output to indicate when the system is in regulation. The MAX8669A and MAX8569B are offered in 6-pin SOT23 and TDFN packages. Prices start at $1.52 each in quantities of 1000.