LKS_PMIC_5V_500
500mA 5V LDO with low dropout, thermal protection, and enable control for MCU power supply.
Product Overview
Description
The LKS_PMIC_5V_500 is a 500mA 5V LDO regulator designed for MCU and digital circuit power supply.
Featuring low dropout voltage of 350mV at 500mA and comprehensive thermal protection, this LDO provides reliable operation.
The enable pin allows power sequencing and system-level power management.
Product Series
LKS
Primary Application
MCU power supply
Key Features
- 500mA output current
- Low dropout 350mV
- Wide input voltage range
- High PSRR 70dB
- Thermal shutdown protection
- Enable control pin
- Low quiescent current
Specifications
| Output Voltage | 5V fixed |
|---|---|
| Output Current | 500mA max |
| Dropout Voltage | 350mV @ 500mA |
| Input Voltage | 5.5V to 20V |
| Quiescent Current | 2mA |
| PSRR | 70dB @ 1kHz |
| Package | SOT-223 |
| Temperature | -40°C to +125°C |
Applications
MCU power supply
Power conversion and supply
Digital circuit power
Electronic system design
Sensor power
Sensor signal conditioning
Reference voltage
Electronic system design
Post-regulation
Power conversion and supply
FAE Expert Insights
"The LKS_PMIC_5V_500 is a solid general-purpose LDO for motor control systems. The 350mV dropout at 500mA is competitive - you can operate from 6V input with 5V output even at full load. I've used this extensively for MCU supplies in 12V and 24V motor drive systems. The 70dB PSRR at 1kHz provides clean power for analog circuits and ADC references. One important consideration: power dissipation at high input voltage - at 24V input, 5V output, 100mA load, you're dissipating 1.9W. Make sure your PCB thermal design can handle it. The SOT-223 package needs copper area for heatsinking. For very high input voltages or currents, consider using a buck converter instead. Overall, reliable and cost-effective for typical applications."
Low dropout and high PSRR make it ideal for MCU supply in motor control systems
— Lisa Huang, BeiLuo
Frequently Asked Questions
What input capacitor is recommended for this LDO?
Input capacitor recommendations for LKS_PMIC_5V_500: (1) Minimum capacitance - 10uF ceramic for stability; (2) Type - X5R or X7R ceramic capacitor, 25V or higher rating; (3) Purpose - supplies transient current during load steps, filters input noise; (4) Placement - close to input pin with short traces; (5) Additional - add 100nF ceramic in parallel for high-frequency decoupling; (6) ESR - ceramic capacitors have very low ESR, ideal for LDOs. If input source is distant or has high impedance, increase capacitance to 22-47uF. Input capacitor prevents oscillation and improves transient response. Always follow datasheet minimum requirements.
Use 10uF X5R/X7R ceramic minimum. Add 100nF for high frequency. Place close to input pin.
How does the enable pin work and how should I use it?
Enable pin operation and usage: (1) Function - turns LDO on/off, active high typically; (2) Threshold - enable voltage > 1.2V turns on, < 0.4V turns off; (3) Current - minimal current required, can be driven directly from MCU GPIO; (4) Sequencing - use for power-up sequencing in multi-rail systems; (5) Shutdown current - typically < 1uA when disabled, important for battery applications; (6) Soft-start - internal soft-start when enabled prevents inrush current. Usage examples: (1) MCU control - GPIO controls LDO for power management; (2) Power sequencing - enable 5V before 3.3V; (3) System shutdown - disable non-critical rails in standby. Leave enable floating or tie to input if not used.
Connect to MCU GPIO for power management. Use for power sequencing in multi-rail systems.
What is PSRR and why does it matter?
PSRR (Power Supply Rejection Ratio) explained: (1) Definition - measure of how well LDO rejects input voltage variations, expressed in dB; (2) Higher is better - 70dB means input ripple is attenuated by 3000x; (3) Frequency dependent - typically high at low frequencies, decreases at high frequencies; (4) Importance - prevents input noise from affecting output, critical for analog circuits and ADC references; (5) Motor control - switching noise from motor drive can couple to supply, high PSRR maintains clean MCU power. The LKS_PMIC_5V_500's 70dB PSRR at 1kHz provides excellent noise rejection for motor control applications. Check PSRR vs frequency curve for your application's noise spectrum.
High PSRR important for analog circuits and ADC references. 70dB provides excellent rejection.
How do I calculate the maximum allowable ambient temperature?
Maximum ambient temperature calculation: (1) Formula - Tambient_max = Tj_max - Pd × Theta-JA; (2) Example - Tj_max = 125°C, Pd = 0.7W, Theta-JA = 50°C/W: 125 - 0.7 × 50 = 90°C; (3) Theta-JA - depends on package and PCB design, SOT-223 typically 40-60°C/W with minimal copper, 20-30°C/W with good heatsinking; (4) Power dissipation - Pd = (Vin - Vout) × Iout, use worst-case values; (5) Margin - keep 10-20°C margin below calculated maximum. If calculated Tambient is too low for your application: increase copper area, add heatsink, reduce load current, reduce input voltage, or use DC-DC converter instead.
Calculate Tambient_max = Tj_max - Pd×Theta-JA. Add copper area if temperature too low.
Can I use this LDO for battery-powered applications?
Battery application considerations: (1) Dropout voltage - 350mV at 500mA means battery can discharge to 5.35V before losing regulation; (2) Quiescent current - 2mA is moderate, will drain battery over time; (3) Shutdown current - < 1uA when disabled, good for standby; (4) Efficiency - poor for large Vin-Vout differences, e.g., 12V to 5V is only 42%; (5) Use cases - good for short battery life or when efficiency not critical; not ideal for long-life battery applications. For battery applications: use if battery voltage close to output (e.g., 6V battery to 5V), use shutdown mode when not active, consider switching to buck converter for better efficiency. The low dropout helps maximize battery life by allowing deeper discharge.
OK for battery if Vin close to Vout. Use shutdown mode. Consider buck for efficiency-critical apps.