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Low-Noise LDOs deliver PSRR performance of 60 dB at 100 kHz.

Press Release Summary:

Achieving 35 µVrms noise at 1.8 V output and 60 dB power supply rejection ratio at 100 kHz, ADP124 and ADP125 help battery-operated portable equipment run longer and more efficiently. LDOs operate from 2.3-5.5 V and provide up to 500 mA output current. While ADP124 offers 31 fixed-output voltage options from 1.75-3.3 V, ADP125 provides adjustable output voltage from 0.8-5.0 V. Quiescent current of 210 µA and 130 mV dropout voltage at 500 mA load further extends device battery life.

Original Press Release:

500-mA LDOs Double the Power Rejection of Competing Devices to Improve Portable and Battery-Powered Equipment Performance

Analog Devices'ADP124 and ADP125 high-performance low-dropout regulators provide low noise and high 60-dB power-supply-rejection ratio at 100 kHz.

NORWOOD, Mass.-- Analog Devices, Inc. (ADI), a global leader in high-performance semiconductors for signal-processing applications, today introduced two low-quiescent-current LDOs (low-dropout linear regulators) that deliver outstanding supply-rejection performance to help battery-operated portable equipment run longer and more efficiently. The new 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 (micro-volts per root mean squared) 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 new 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. To download the datasheet, please visit or

"Designing for portable products requires a small solution size, low power dissipation, and high power-supply rejection for the best mixed-signal processing performance, particularly during instances where the power supply is a hidden source of noise," said Walt Heinzer, product line manager, Power Management Group, Analog Devices. "By offering a superior 60-dB PSRR, these high-performance LDOs are 30 dB--or 30X better on a logarithmic scale--when compared to commodity LDOs that offer 25 dB or 30 dB. They surpass competitive alternatives by offering the best combination of very-low dropout, low noise, and high power-supply-rejection ratio at a very competitive price."

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 mm x 2 mm x 0.55 mm LFCSP package or an 8-lead exposed paddle MSOP package.

Key Features and Benefits
  • 60-dB PSSR at 100 kHz keeps higher frequencies from mixing into RF (radio frequency) loads resulting in improved phase-noise performance.
  • An initial 1 percent accuracy provides tight tolerances for core voltage rails in FPGA applications.
  • Very-low-dropout voltage of 130 mV at 500 mA minimizes power loss and allows operation further down the battery discharge curve.
  • Low noise of 35 µVRMS at 1.8Vout provides clean power supply to high-performance A/D converters without the addition of extra output bypass capacitors.
  • Stability with 1 µF Cout ceramic capacitors maintains compact footprint for space sensitive applications.
    Availability and Pricing

    Product Availability Vout Price Each Package Options
    ADP124 Volume production now Fixed per 1,000 3 mm x 5 mm
    1.75 V to 3.3 V $0.42 8-Lead EP MSOP
    2 mm x 2 mm LFCSP-8

    ADP125 Volume production now Adjustable $0.42 3 mm x 5 mm
    0.8 V to 5 V 8-Lead EP MSOP
    2 mm x 2 mm LFCSP-8

    Redykit(TM) Evaluation Kits are available to simplify product evaluation. The kits contain evaluation boards and additional devices with other voltage options. In addition, a linear regulator tool can be downloaded from the ADIsimPower Resources and Tools for Power Management tab on ADI's power management website. The tool generates a bill of materials with complete operating conditions to finish the full circuit design.

    ADI in Power Management
    Analog Devices brings world-class signal processing prowess to a portfolio of innovative power management ICs that complement high-performance signal processing functions in a wide range of portable and fixed-power applications in consumer electronics, medical equipment, industrial and instrumentation, and communications infrastructure. By supporting signal chain design requirements, such as dynamic range, transient performance, and reliability, ADI helps customers solve complex power challenges easily and quickly, differentiate their products and get to market faster. Learn more about ADI's power management solutions at

    About Analog Devices
    Innovation, performance, and excellence are the cultural pillars on which Analog Devices has built one of the longest standing, highest growth companies within the technology sector. Acknowledged industry-wide as the world leader in data conversion and signal conditioning technology, Analog Devices serves over 60,000 customers, representing virtually all types of electronic equipment. Celebrating over 40 years as a leading global manufacturer of high-performance integrated circuits used in analog and digital signal processing applications, Analog Devices is headquartered in Norwood, Massachusetts, with design and manufacturing facilities throughout the world. Analog Devices' common stock is listed on the New York Stock Exchange under the ticker "ADI" and is included in the S&P 500 Index.

    Redykit(TM) is a trademark of a Analog Devices, Inc.

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