During shutdown, the battery input is connected to the output through the inductor and the internal synchronous rectifier of the MAX8569. This allows the input battery (rather than a separate backup battery) to provide backup power for devices such as an idled microcontroller, SRAM, or real-time clock, without the usual diode forward drop. Drive SHDN to VOUT (logic-high) to enable the IC for normal operation.
If the voltage rail sourced by the boost regulator (VOUT) needs to be controlled, and completely switched off , there are two methods to accomplish this:
Insert a load switch or simple P-FET in series between VBOOST and the Load.
Select a Boost Regulator with TRUE SHUTDOWN.
Maxim has a number of High-Efficiency, Synchronous Boost Regulators with TRUE SHUTDOWN :
MAX17220-MAX17225 for Nanopower Iq applications
MAX17250 for 18V and below applications
MAX20471-MAX20473 for 5.25V and below applications
MAX77231 for low current, ultra-low noise and low ripple
MAX8815A and MAX1947 for ultra-high efficiency and simplicity from a very low input voltage, to name a few.