The internal charge pump of the LTC3260 and LTC3261 function in either low quiescent current Burst Mode® operation or low noise constant frequency mode at up to 88% efficiency. In Burst Mode operation the charge pump output regulates to –0.94 • VIN. Also, in Burst Mode operation the LTC3261 draws only 60μA of quiescent current, while the LTC3260 draws only 100uA with both LDOs enabled. Constant frequency operation offers low input and output ripple; in this mode the charge pump produces an output equal to –VIN and operates at a fixed 500kHz or to a programmed value between 50kHz to 500kHz using an external resistor. Other IC features include low external parts count with ceramic capacitor stability, soft-start circuitry to prevent excessive current flow during start-up, plus short circuit and thermal protection. The LTC3260 and LTC3261 are well-suited for a variety of applications such as low noise bipolar/inverting supplies from a high voltage input, industrial/instrumentation low noise bias generators, portable medical equipment and automotive infotainment systems.
The LTC3260 is available in a low-profile (0.75mm) 3mm x 4mm 14-lead DFN package and a 16-lead MSOP package, both with a backside thermal pad. The LTC3261 is available in a 12-lead MSOP package with backside thermal pad. For both devices, the E- and I-grade operating junction temperature is -40°C to +125°C. 1000-piece pricing for the E grade starts at $3.40 each for the LTC3260 and $2.87 each for the LTC3261. Both devices are available from stock.