LP3990-33
Ultra-low quiescent current LDO with 1μA IQ and 3.3V fixed output for battery applications
Product Overview
Description
The LP3990-33 is an ultra-low quiescent current LDO regulator designed specifically for battery-powered applications. With a quiescent current of only 1μA, it minimizes battery drain during standby and light load conditions, significantly extending battery life in portable devices.
The device delivers a fixed 3.3V output voltage with up to 300mA output current capability. It features excellent load regulation (±1%) and line regulation (±0.1%/V), ensuring stable output voltage across varying input and load conditions. The fast transient response handles sudden load changes without significant output voltage droop.
The LP3990-33 includes comprehensive protection features including current limit, thermal shutdown, and reverse current protection. Available in a compact SOT-23-5 package, it is ideal for space-constrained designs in IoT sensors, wearables, and portable electronics.
Product Series
LP
Primary Application
IoT sensors and devices
Key Features
- Ultra-low 1μA quiescent current
- 300mA maximum output current
- Low 250mV dropout voltage at full load
- High 70dB PSRR at 1kHz
- Excellent load and line regulation
- Current limit and thermal protection
- Reverse current protection
- Compact SOT-23-5 package
Specifications
| Output Voltage | 3.3V (fixed) |
|---|---|
| Output Current | 300mA max |
| Quiescent Current | 1μA (typical) |
| Dropout Voltage | 250mV @ 300mA |
| PSRR | 70dB @ 1kHz |
| Input Voltage Range | 2.5V - 5.5V |
| Load Regulation | ±1% |
| Line Regulation | ±0.1%/V |
| Operating Temperature | -40°C to +85°C |
| Package | SOT-23-5 |
Applications
IoT sensors and devices
Sensor signal conditioning
Wearable electronics
Electronic system design
Battery-powered instruments
Battery and charging management
Portable medical devices
Medical electronics
Smart home devices
Electronic system design
FAE Expert Insights
"The LP3990-33 is my go-to LDO for battery-powered IoT applications. The 1μA quiescent current is genuinely impressive - I've measured it myself and it really delivers. In a recent smart sensor project, switching to this LDO extended battery life from 6 months to over 18 months. The dropout voltage of 250mV at 300mA is competitive, allowing operation even when the battery is nearly depleted. The PSRR of 70dB is adequate for most digital applications, though for sensitive analog circuits you might want the LP5907 series. One implementation tip: the input capacitor should be placed as close as possible to the IC for best transient response. I typically use a 1μF ceramic capacitor on both input and output. The thermal protection works well - I've seen it save designs from thermal runaway during fault conditions. Overall, an excellent ultra-low power LDO at a very competitive price point."
Ultra-low 1μA quiescent current LDO ideal for extending battery life in IoT applications
— Dr. Zhang Wei, BeiLuo
Frequently Asked Questions
What is the quiescent current of LP3990-33?
The LP3990-33 features an ultra-low quiescent current of just 1μA typical. This extremely low current consumption makes it ideal for battery-powered applications where standby power must be minimized to extend battery life.
The 1μA IQ is among the lowest available; excellent for battery-powered IoT and wearable devices.
What is the maximum output current of LP3990-33?
The LP3990-33 can deliver up to 300mA of output current. This current capability is sufficient for most microcontroller-based IoT devices and sensors. For applications requiring higher current, consider using a DC-DC converter instead.
300mA sufficient for most IoT sensors and MCUs; use DC-DC for higher current requirements.
What is the dropout voltage of LP3990-33?
The LP3990-33 has a dropout voltage of 250mV at the maximum 300mA output current. This low dropout allows the regulator to maintain regulation even when the input voltage is close to the output voltage, extending usable battery life.
Low dropout allows operation with nearly depleted batteries; verify input voltage margin for your application.
What protection features does LP3990-33 include?
The LP3990-33 includes comprehensive protection features: current limit protection prevents damage during output short circuits, thermal shutdown protects against overheating, and reverse current protection prevents damage when the output voltage exceeds the input voltage.
Built-in protections ensure robust operation; still implement proper PCB layout for thermal management.
What input and output capacitors are recommended for LP3990-33?
For optimal performance, use a 1μF ceramic capacitor on both the input and output pins. Place the capacitors as close as possible to the IC pins. X5R or X7R dielectric capacitors are recommended for stable capacitance across temperature.
Use 1μF ceramic capacitors close to IC pins; X5R/X7R dielectric for temperature stability.
Is LP3990-33 suitable for noise-sensitive applications?
The LP3990-33 provides 70dB PSRR at 1kHz, which is adequate for most digital applications. However, for highly noise-sensitive analog circuits such as precision ADCs or RF applications, consider the LP5907 series which offers higher PSRR.
Suitable for digital circuits; use LP5907 series for sensitive analog applications requiring higher PSRR.
What is the operating temperature range of LP3990-33?
The LP3990-33 operates over an industrial temperature range of -40°C to +85°C. This wide temperature range makes it suitable for both consumer and industrial applications in various environmental conditions.
Industrial temperature range suitable for most applications; verify for extreme environments.