New high voltage charge pumps have been released by Linear Technology Corporation. The LTC3261 is a high voltage inverting charge pump that is able to achieve up to 100mA of output current. The LTC3260 has the same charge pump, but also includes both positive and negative LDO regulators that can source up to 50mA output current each.

The negative LDO post regulator is powered from the inverting charge pump output. The positive and negative LDO output voltages can be adjusted down to 1.2V and -1.2V, respectively using external resistor dividers. Both devices operate over a wide 4.5V to 32V input voltage range.

The internal charge pump of the two devices  function in either low quiescent current Burst Mode operation or low noise constant frequency mode at up to 88 percent 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.

Both devices can be applied to 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) 3mmby 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.

Linear Technology Corporation

www.linear.com/product/LTC3260

www.linear.com/product/LTC3261