Adjustable low-noise positive and negative-output charge pump with integrated LDO

The Texas Instruments LM27762 delivers very low-noise positive and negative outputs that are adjustable between ±1.5V and ±5V. Input-voltage range is from 2.7V to 5.5V, and output current goes up to ±250mA. With an operating current of only 390µA and 0.5µA typical shutdown current, the device provides ideal performance for power amplifier and DAC bias and other high-current, low-noise negative voltage needs. The device provides a small solution size with few external components. Negative voltage is generated by a regulated inverting charge pump followed by a low-noise negative LDO. The inverting charge pump of the device operates at 2MHz (typical) switching frequency to reduce output resistance and voltage ripple. Positive voltage is generated from the input by a low-noise positive LDO. Positive and negative outputs of device have dedicated enable inputs. These outputs support independent timing for the positive and negative rails for specific system power-sequence needs. Enable inputs can be also shorted together and connected to the input voltage. The device has an optional Power Good feature.