Linear Technology's LTC3240-2.5/3.3, regulated buck-boost charge pumps, the LTC3240-2.5/3.3 are capable of output currents as high as 150 mA from a wide ranging input of 1.8 V to 5.5 V. When the input voltage exceeds the output voltage, the device operates in low-dropout regulator (LDO) mode. If the input voltage drops to within 100 mV of the output voltage, the device automatically switches into a boost mode. For light loads it operates in a high-efficiency, low power Burst Mode to extend battery life.
When boosting higher loads the LTC3240 automatically switches into low noise constant frequency operation. Its patented constant-frequency architecture offers both low input and low output ripple and its high 1.2-MHz switching frequency enables the use of tiny external ceramic capacitors.Featuring a regulated output, the LTC3240 is well suited for a variety of applications such as 2- to 3-AA cell alkaline/NiMH or 1-cell Li-Ion battery to 2.5V/3.3V step-up/step-down conversion in portable products. The device's low ripple performance makes it ideal for applications sensitive to variable-frequency operation such as audio and RF supplies. The LTC3240EDC-2.5 and LTC3240EDC-3.3 are available in a 6-lead DFN 2-mm x 2-mm x 0.75-mm package. 1000-piece pricing starts at $1.60 each.