The TPS61098x is an ultra-low power solution optimized for products powered by either a one-cell or two-cell alkaline, NiCd or NiMH, one-cell coin cell battery or one-cell Li-Ion or Li-polymer battery. To simplify system design and save PCB space, the TPS61098x integrates an LDO or load switch with a boost converter (different configurations for different versions) to provide two output rails in a compact package. The boost output V_(MAIN) is designed as an always-on supply to power a main system, and the LDO or load switch output V_(SUB) is designed to power peripheral devices and can be turned off.

The TPS61098x features two modes controlled by MODE pin: Active mode and Low Power mode. In Active mode, both outputs are enabled, and the transient response performance of the boost converter and LDO/load switch are enhanced, so it is able to respond load transient quickly. In Low Power mode, the LDO/load switch is disabled, so the peripherals can be disconnected to minimize the battery drain. Besides that, the boost consumes only 300 nA quiescent current in Low Power mode, so up to 88% efficiency at 10 μA load can be achieved to extend the battery run time. The TPS610982 is an exception. Its LDO is always on in both Active mode and Low Power mode. The main differences between the two modes of the TPS610982 are the quiescent current and performance. Refer to Section 8.4.1 for details.

The TPS61098x supports automatic pass-through function in both Active mode and Low Power mode. When V_IN is detected higher than a pass-through threshold, which is around the target V_(MAIN) voltage, the boost converter stops switching and passes the input voltage through inductor and internal rectifier switch to V_(MAIN), so V_(MAIN) follows V_IN; when V_IN is lower than the threshold, the boost works in boost mode and regulates V_(MAIN) at the target value. The TPS61098x can support different V_(MAIN) target values in Active mode and Low Power mode to meet various requirements. For example, for TPS61098, the set value of V_(MAIN) is 4.3 V in Active mode but 2.2 V in Low Power mode.