SGM2019
High-PSRR low-dropout regulator with 300mA output current, ultra-low noise of 30uVrms, and high PSRR of 70dB at 1kHz.
Product Overview
Description
The SGM2019 is a high-performance low-dropout linear regulator designed for noise-sensitive applications.
With ultra-low output noise of just 30uVrms and high PSRR of 70dB at 1kHz, it provides clean power for analog circuits.
The device delivers up to 300mA output current with low dropout voltage of 270mV at full load.
Product Series
SGM
Primary Application
RF power supplies
Key Features
- Ultra-low output noise: 30uVrms
- High PSRR: 70dB at 1kHz
- Low dropout voltage: 270mV
- 300mA output current
- Fast transient response
Specifications
| Input Voltage | 2.5V - 5.5V |
|---|---|
| Output Voltage | 1.2V - 3.3V (fixed/adj) |
| Output Current | 300mA |
| Dropout Voltage | 270mV @ 300mA |
| PSRR | 70dB @ 1kHz |
| Package | SOT-23-5, SC-70-5 |
Applications
RF power supplies
Electronic system design
Audio circuits
Electronic system design
Precision ADC/DAC
Data acquisition and conversion
Camera modules
Electronic system design
Sensor power supplies
Sensor signal conditioning
FAE Expert Insights
"The SGM2019 is my top recommendation for powering noise-sensitive analog circuits. The combination of 30uVrms noise and 70dB PSRR at 1kHz makes it ideal for RF and precision measurement applications. I have successfully used this LDO in audio codec power supplies, camera module VDD rails, and precision reference circuits. The fast transient response handles load steps well without significant voltage undershoot. For best noise performance, I recommend adding a 10nF bypass capacitor on the BYP pin and using low-ESR ceramic output capacitors."
Excellent noise performance for sensitive analog and RF applications
— Jennifer Zhang, BeiLuo
Frequently Asked Questions
What is the minimum input-output voltage difference for the SGM2019?
The SGM2019 requires a minimum dropout voltage of 270mV at full load (300mA). At lighter loads, the dropout voltage is lower - approximately 100mV at 100mA and 50mV at 50mA. For proper regulation, the input voltage must exceed the output voltage by at least the dropout voltage plus any additional margin for transient conditions. In low-dropout applications, ensure the input voltage remains stable and above the required threshold.
Ensure Vin > Vout + 300mV for reliable operation. For very low dropout requirements, contact us for alternative recommendations.
How can I further reduce output noise from the SGM2019?
To minimize output noise: 1) Use the BYP pin with a 10nF capacitor to ground - this bypasses the internal reference and significantly reduces noise; 2) Use low-ESR ceramic output capacitors (X5R or X7R dielectric); 3) Add a 1uF ceramic capacitor close to the load for high-frequency decoupling; 4) Keep input traces short and away from switching noise sources; 5) Use a clean input supply or pre-regulate with a switching converter followed by the LDO. With proper design, output noise can be reduced below 30uVrms.
Always use the BYP pin capacitor for lowest noise. Contact our FAE team for noise-sensitive design guidance.
What is the PSRR of the SGM2019 at different frequencies?
The SGM2019 PSRR varies with frequency: 70dB at 1kHz, 60dB at 10kHz, 45dB at 100kHz, and 30dB at 1MHz. The high PSRR at low frequencies effectively rejects line ripple from AC adapters and switching converter outputs. At higher frequencies, PSRR decreases but can be improved with additional output filtering. For applications with significant high-frequency noise on the input, consider adding an input pi-filter or using the LDO in combination with a switching pre-regulator.
The SGM2019 provides excellent low-frequency PSRR. For high-frequency noise, add additional filtering or contact us for alternatives.
Can the SGM2019 be used in a dual-supply configuration?
The SGM2019 is designed for single-supply operation and cannot directly generate negative voltages. However, it can be used in dual-supply systems by powering it from the positive rail to generate a clean positive supply. For negative voltage generation, consider using an inverting charge pump or buck-boost converter followed by a negative LDO. In split-supply analog circuits, use separate SGM2019 devices for the positive and negative rails, each powered from the appropriate supply.
Use SGM2019 for positive rail regulation. Contact us for negative voltage generation solutions.
What protection features does the SGM2019 include?
The SGM2019 includes several protection features: 1) Current limiting - protects against output short circuits by limiting current to a safe level; 2) Thermal shutdown - disables the output if the die temperature exceeds safe limits, automatically resuming when cooled; 3) Reverse current protection - prevents current flow from output to input when the output is higher than input; 4) Safe operating area protection - ensures the device operates within safe power dissipation limits. These features protect both the LDO and the powered circuitry.
The built-in protection features make the SGM2019 robust for general applications. Ensure proper thermal design for high-power dissipation scenarios.