ADP7156ARDZ-1.8-R7

Overview

The ADP7156ARDZ-1.8-R7 is a fixed-output linear regulator providing 1.8 V at up to 1.2 A load current. It operates from an input voltage range of 2.3 V to 5.5 V with a typical dropout voltage of 120 mV at full load. The device features ultralow noise, delivering 0.9 µV rms integrated noise (100 Hz to 100 kHz) and 1.7 nV/√Hz spectral density (10 kHz to 1 MHz). Power supply rejection ratio reaches 80 dB from 1 kHz to 100 kHz. Quiescent current is 4.0 mA at no load and 7 mA at 1.2 A. Initial output accuracy is ±0.6% at 25°C, expanding to ±1.5% over line, load, and temperature ranges.

Feature Summary

• Ultralow noise architecture optimized for RF applications
• High power supply rejection ratio across wide frequency bands
• Precision enable pin with defined logic thresholds
• Stable operation with standard ceramic capacitors

Applications

• Phase-locked loops (PLLs)
• Voltage controlled oscillators (VCOs)
• Communications infrastructure
• Backhaul and microwave links

Procurement Notes

Verify the specific suffix RD-8-4 against the latest datasheet revision G ordering guide to confirm package and tape/reel specifications. Confirm that the automotive qualification status aligns with system requirements if applicable. Ensure input and output capacitor selections meet the minimum capacitance and ESR requirements specified in the application information section to maintain stability.

Selection Notes

Select this component when low noise and high PSRR are critical for sensitive analog or RF circuits. The fixed 1.8 V output eliminates external resistor networks. Verify that the input voltage remains within the 2.3 V to 5.5 V range under all operating conditions. Consider thermal dissipation capabilities based on the PCB layout and ambient temperature to ensure junction temperature limits are not exceeded during peak load currents.

Part Context

The ADP7156 belongs to Analog Devices' family of high-performance RF linear regulators. It shares architectural similarities with the ADP7157 and ADP7158 but offers distinct current ratings and noise profiles. The device utilizes a proprietary P-channel MOSFET pass transistor design to achieve superior transient response and noise performance compared to standard LDOs.

Replacement Considerations

ADP7157ACPZ-1.8-R7

FAQ

What is the recommended bypass capacitor value for the BYP pin?

A 1 µF capacitor is typically connected between the BYP pin and ground to filter the reference buffer. Capacitors as small as 0.1 µF can be used, though this increases output noise.

How does the EN pin control the regulator state?

Driving the EN pin high turns on the VOUT output, while driving it low turns it off. For automatic startup, the EN pin can be tied directly to VIN.

What type of capacitors are recommended for stability?

X5R or X7R dielectric ceramic capacitors are recommended. Y5V and Z5U dielectrics are not recommended due to poor temperature and DC bias characteristics.