XB-LD0333
Low-dropout regulator with ultra-low noise and high PSRR for sensitive analog and RF applications.
Product Overview
Description
The XB-LD0333 is a low-noise, high-PSRR LDO regulator designed for noise-sensitive applications.
It provides clean, stable power for analog circuits, RF systems, and precision sensors.
The ultra-low dropout voltage and low quiescent current make it ideal for battery-powered devices.
Product Series
XB
Primary Application
RF and communication systems
Key Features
- Ultra-low output noise 10μVRMS
- High PSRR 70dB at 1kHz
- Low dropout voltage 120mV
- Low quiescent current 50μA
- Excellent load/line regulation
- Current limit and thermal protection
- Stable with ceramic capacitors
- Small SOT-23-5 package
Specifications
| Type | Low-Dropout Regulator |
|---|---|
| Input Voltage | 2.5V to 5.5V |
| Output Voltage | 1.2V to 3.3V (fixed/adjustable) |
| Max Current | 300mA |
| Dropout Voltage | 120mV at 300mA |
| Output Noise | 10μVRMS (10Hz-100kHz) |
| PSRR | 70dB at 1kHz |
| Package | SOT-23-5 |
Applications
RF and communication systems
Communication and interface
Precision analog circuits
Electronic system design
Sensor power supplies
Sensor signal conditioning
Audio equipment
Electronic system design
Battery-powered devices
Battery and charging management
FAE Expert Insights
"The XB-LD0333 is my go-to LDO for noise-sensitive applications. The 10μV noise figure is excellent for powering precision ADCs, RF circuits, and audio equipment. The high PSRR ensures clean output even with noisy input supplies. I particularly appreciate the stable operation with small ceramic capacitors - no large tantalums needed. The dropout voltage is low enough for 3.3V output from Li-ion batteries down to 3.6V. For portable and sensitive analog applications, this LDO delivers premium performance at a competitive price."
Ultra-low noise 10μVRMS with high PSRR
— David Chen, BeiLuo
Frequently Asked Questions
What is PSRR and why is it important?
PSRR (Power Supply Rejection Ratio) measures how well an LDO rejects noise and ripple on the input supply. Higher PSRR means less input noise appears at the output. This is critical for sensitive analog circuits like ADCs, DACs, and RF systems where supply noise can degrade performance. XB-LD0333's 70dB PSRR at 1kHz means input noise is attenuated by 3000x. PSRR is typically highest at low frequencies and decreases at higher frequencies.
Select high PSRR LDOs for sensitive analog circuits. XB-LD0333 excellent for RF and precision applications.
Can XB-LD0333 operate with input voltage close to output voltage?
Yes, XB-LD0333 has a low dropout voltage of 120mV at 300mA, meaning it can maintain regulation with input just 120mV above output. At lighter loads, dropout is even lower (50mV at 100mA). This makes it suitable for battery applications where input voltage drops as battery discharges. For example, it can maintain 3.3V output from a Li-ion battery down to about 3.45V.
XB-LD0333 excellent for battery applications. Calculate dropout at max load current.
What output capacitor should I use with XB-LD0333?
XB-LD0333 is stable with ceramic capacitors as small as 1μF. Recommended: 2.2-4.7μF X5R or X7R ceramic capacitor. Place the capacitor close to the output pins for best transient response. Larger capacitors (10μF) improve transient response but increase startup time. Use low-ESR ceramic capacitors for best noise performance. Avoid tantalum or electrolytic capacitors unless specifically required.
Use 2.2-4.7μF ceramic capacitor. Place close to output pins.
How does the enable pin work on XB-LD0333?
The ENABLE pin controls the LDO on/off state. Drive ENABLE high (>1.2V) to turn on the LDO, low (<0.4V) to shut down. In shutdown, quiescent current drops to <1μA. The enable threshold is compatible with standard logic levels. An internal pull-down resistor ensures the LDO remains off if ENABLE is left floating. Use ENABLE for power sequencing, power saving, or soft-start control in multi-rail systems.
Use ENABLE for power control and sequencing. Compatible with standard logic levels.
Is XB-LD0333 suitable for RF power supply applications?
Yes, XB-LD0333 is excellent for RF power supplies due to its ultra-low noise (10μVRMS) and high PSRR. RF circuits are sensitive to power supply noise which can appear as spurious signals or phase noise. The XB-LD0333's noise performance rivals much more expensive RF-specific LDOs. Use it to power VCOs, PLLs, mixers, and ADCs in communication systems. Add a small ferrite bead and capacitor for additional high-frequency filtering if needed.
XB-LD0333 excellent for RF applications. Consider additional filtering for critical circuits.