ADM7172ACPZ-1.8-R7

Overview

The ADM7172ACPZ-1.8-R7 is a fixed-output low dropout linear regulator manufactured by Analog Devices Inc., providing a regulated 1.8 V output with a maximum load current of 2 A. It operates within an input voltage range of 2.3 V to 6.5 V and features ultralow noise performance, delivering 5 µV rms in the 100 Hz to 100 kHz bandwidth. The device achieves high power supply rejection ratio (PSRR) of 60 dB at 100 kHz and fast transient response, settling within 1.5 μs for a 1 mA to 1.5 A load step. Quiescent current is 0.7 mA at no load, dropping to 0.25 μA during shutdown. It includes precision enable, adjustable soft start, and thermal overload protection, housed in an 8-lead 3 mm × 3 mm LFCSP package.

Feature Summary

• Ultralow noise architecture delivers 5 µV rms output noise independent of the fixed output voltage setting.
• High power supply rejection ratio maintains 60 dB attenuation at 100 kHz under heavy loading conditions.
• Fast transient response capability settles output voltage deviations within 1.5 μs following significant load steps.
• Integrated precision enable pin allows precise control over startup sequencing and shutdown states.

Applications

• Regulation for noise-sensitive analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuits
• Powering precision amplifiers and phase-locked loops (PLLs) or voltage-controlled oscillators (VCOs)
• Clocking integrated circuits requiring stable low-noise voltage rails

Procurement Notes

Verify the specific suffix -R7 indicates reel packaging when reviewing distributor listings. Confirm the 1.8 V fixed output variant matches the design requirement, as the ADM7172 family offers multiple voltage options. Ensure the 8-lead LFCSP package footprint aligns with the printed circuit board layout constraints. Check for moisture sensitivity level requirements if the component has been stored for extended periods prior to assembly.

Selection Notes

Select this component when designing systems that require high current delivery up to 2 A alongside stringent noise specifications. The fixed 1.8 V output eliminates the need for external feedback resistors, simplifying the bill of materials. Consider the small 4.7 µF ceramic capacitor stability requirement, which reduces overall system volume compared to regulators needing larger electrolytic outputs. Evaluate thermal dissipation needs based on the difference between input voltage and the 1.8 V output at full load.

Part Context

This part belongs to the ADM7172 series of CMOS low dropout linear regulators from Analog Devices. The series is designed for high-performance analog and mixed-signal applications, offering superior line and load transient response compared to standard LDOs. It shares architectural similarities with the ADM7170 and ADM7171 but provides higher current capacity. The device supports both fixed and adjustable output configurations within the broader product line.

Replacement Considerations

The ADM7171ACPZ-1.8-R7 serves as a lower-current alternative within the same package, rated for 1 A output. For applications requiring higher efficiency, switching regulators like the ADP2371ACPZ-1.8-R7 may be considered, though they differ fundamentally in topology and noise characteristics. Direct pin-compatible replacements should be verified against datasheet electrical parameters to ensure compatibility with existing decoupling capacitors.