LDOs double the power rejection of competing devices

The ldos are designed to achieve low noise of 35µVrms at 1.8V output. Operating from an input voltage between 2.3 and 5.5V and providing up to 500mA of output current down to a 0.8V output, the units also feature a low quiescent current of 210µA and a 130mV dropout voltage at a 500mA load, designed to further improve portable equipment operating efficiency over a wide input voltage range. "Designing for portable products requires a small solution size, low power dissipation and high power supply rejection for the best mixed signal processing performance," said Walt Heinzer, product line manager, Analog Devices. "By offering a superior 60dB psrr, these high performance ldos are 30dB - or 30X better on a logarithmic scale - when compared to commodity ldos that offer 25 or 30 dB. They surpass competitive alternatives by offering the best combination of low dropout, low noise and high power supply rejection ratio at a competitive price." The ADP124 offers 31 fixed output voltage options from 1.75 to 3.3V. In addition, the ADP125 provides an adjustable output voltage between 0.8 and 5V using an external voltage divider. Both of the devices are designed for stable operation with small 1µF ceramic input and output capacitors to meet the requirements of high performance, space constrained applications.