Analog Devices, Inc. (ADI) has introduced two low-quiescent-current LDOs (low-dropout linear regulators), which it claims will deliver supply-rejection performance to help battery-operated portable equipment run longer and more efficiently.  ADI announced that the ADP124 and ADP125 LDOs have excellent PSRR (power-supply-rejection ratio) performance of 60 dB at 100 kHz, which is twice that of the nearest competing LDOs, and achieve low noise of 35 µVrms at 1.8-V output. Operating from an input voltage between 2.3 V and 5.5 V and providing up to 500 mA of output current down to a 0.8-V output, the LDOs also feature a low quiescent current of 210 μA and a 130-mV dropout voltage at a 500-mA load, which further improves portable equipment operating efficiency over a wide input-voltage range.

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The ADP124 offers 31 fixed-output voltage options from 1.75 V to 3.3 V. The ADP125 LDO provides an adjustable output voltage between 0.8 V and 5.0 V using an external voltage divider. The ADP124 and ADP125 are specifically designed for stable operation with tiny 1-μF ceramic input and output capacitors to meet the requirements of high-performance, space-constrained applications. The LDOs are available in a compact 2- by 2- by 0.55-mm lead frame chip scale packaging (LFCSP) or an eight-lead exposed paddle mini small outline package (MSOP).

According to ADI, the regulators’ 60-dB PSSR at 100 kHz keeps higher frequencies from mixing into RF (radio frequency) loads resulting in improved phase-noise performance. They also have an initial 1% accuracy that provides tight tolerances for core voltage rails in FPGA applications and a very-low-dropout voltage of 130 mV at 500 mA that minimizes power loss and allows operation further down the battery discharge curve. They also provide a clean power supply to high-performance analog-to-digital converters without the addition of extra output bypass capacitors. They are very stable as well, with 1-µF Cout ceramic capacitors that maintain compact footprint for space sensitive applications.

The ADP124 and the ADP125 both cost $0.42 in thousand-unit quantities.

Analog Devices