Tiny Low-Dropout Regulator Delivers Negative Voltages

Intended for battery-operated equipment where a small package, low noise and low-power operation are critical, the MIC5270 supplies regulated negative voltages with current of up to 100 mA. The device comes in the IttyBitty SOT-23-5 package and is capable of operating with smaller, less expensive external capacitors than traditional LDOs.A common application is for power amplifiers in cellular phones. The GaAs MESFETs typically employed require a negative gate bias. The MIC5270 fits the bill handily for such space-limited applications.Precisely trimmed to 2% output tolerance, the device has a low quiescent current of 80 µA. Dropout voltage is 600 mV maximum at 100 mA of output current. The part is well protected with current limit and thermal shutdown capabilities. In addition, a -20V (maximum) input voltage range ensures that the regulator will survive power supply spikes that can kill other LDO regulators.