LTC3539/-2 can deliver up to 900mA of continuous output current (at 3.3V) from dual alkaline cells or 900mA of continuous output current (at 5V) from a single-cell Li-Ion battery. Synchronous rectification enables efficiencies up to 94 per cent, while Burst Mode operation lowers quiescent current to only 10uA, providing extended battery run-time in handheld applications. The combination of a 2mm x 3mm DFN-8 package and a constant switching frequency of 1MHz (2MHz for the LTC3539-2) minimise both inductor and capacitor sizes, providing a tiny solution footprint required in handheld applications.
LTC3539/-2 have internal switches with an RDS(ON) of 0.09 Ohm (N-Channel) and 0.125 Ohm (P-Channel) to deliver efficiencies as high as 94 per cent, Linear claimed. The output disconnect feature allows the output to be completely discharged in shutdown. It also limits the inrush of current during start-up, minimising surge currents seen by the input supply.
LTC3539/-2 will also regulate the output voltage when the input voltage exceeds the output voltage, making the device compatible with any battery chemistry. For applications demanding the lowest possible noise operation, LTC3539/-2 can be set via an external pin to operate in a continuous frequency mode.
This version runs in continuous mode at all current levels to minimise possible interference of switching noise with noise-sensitive circuitry slightly reducing light load efficiency. Additional features include anti-ringing control, short-circuit protection, soft-start and thermal protection.
LTC3539EDCB and LTC3539EDCB-2 are both available in 8-lead 2mm x 3mm DFN packages. 1,000-piece pricing starts at $2.50 each. |
