Key Selection Information
| Selection Parameter | Confirmed Information |
|---|---|
| Input voltage | 2.3 V to 6.5 V |
| Fixed output | 3.3 V |
| Maximum load current | 2 A |
| Output noise | 5 µV rms, 100 Hz to 100 kHz |
| PSRR | 60 dB at 100 kHz |
| Dropout | 172 mV at 2 A, VOUT = 3 V family condition |
| Accuracy | ±1.5% over line, load, and temperature |
| Output capacitor | Stable with 4.7 µF ceramic |
| Package | 8-lead 3 mm × 3 mm LFCSP, CP-8-21 |
| Operating temperature | −40°C to +125°C |
Product Overview
ADM7172ACPZ-3.3-R7 is the fixed 3.3 V version of the ADM7172 2 A low-noise CMOS LDO. Although the family accepts inputs down to 2.3 V, a 3.3 V output requires VIN to stay above 3.3 V by enough headroom for regulation at the intended load.
The fixed-output order code provides the family low-noise and high-PSRR architecture without an external feedback divider. It is suited to high-current 3.3 V analog rails where supply cleanliness matters more than conversion efficiency alone.
Key Features
- Fixed 3.3 V output with up to 2 A load current.
- 5 µV rms output noise.
- 60 dB PSRR at 100 kHz.
- Stable with a 4.7 µF ceramic output capacitor.
Functional Highlights
The -3.3-R7 suffix fixes the output voltage; the related ACPZ-R7 part without the voltage suffix is adjustable.
At high current, LDO loss becomes heat. The voltage dropped from VIN to 3.3 V, multiplied by load current, sets the main thermal burden.
Application Fit
- 3.3 V supplies for ADC and DAC circuits.
- Precision amplifier and clocking rails.
- PLL/VCO and mixed-signal supply filtering.
- Instrumentation and communications circuitry.
Design Considerations
- Do not use the adjustable-version feedback divider; this model is internally fixed at 3.3 V.
- Verify VIN headroom above 3.3 V across load, line, and temperature.
- Calculate thermal dissipation and use the exposed pad/PCB copper appropriately.
- Meet the 4.7 µF output-capacitor requirements and keep sensitive nodes away from switching noise.
Product Status
Manufacturer status: RECOMMENDED FOR NEW DESIGNS
Analog Devices currently marks the ADM7172 family RECOMMENDED FOR NEW DESIGNS.
Related Engineering Resources
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