SLM3500
Silan SLM3500 low-dropout linear regulator with ultra-low noise and high PSRR for sensitive analog and RF applications.
Product Overview
Description
The SLM3500 is a high-performance low-dropout (LDO) linear regulator designed for noise-sensitive applications.
Features ultra-low output noise of 15μVrms and high power supply rejection ratio (PSRR) of 75dB at 1kHz.
Ideal for powering RF circuits, precision ADCs, and audio applications where clean power is critical.
Product Series
SLM
Primary Application
RF power supplies
Key Features
- Ultra-low output noise: 15μVrms (10Hz-100kHz)
- High PSRR: 75dB at 1kHz, 50dB at 100kHz
- Low dropout voltage: 250mV at 500mA
- Wide input voltage range: 2.5V to 5.5V
- Adjustable output: 1.2V to 4.5V
- Fast transient response
- Thermal shutdown and current limit protection
Specifications
Applications
RF power supplies
Electronic system design
Precision ADC/DAC reference
Data acquisition and conversion
Audio circuits
Electronic system design
Camera sensors
Sensor signal conditioning
Communication modules
Communication and interface
FAE Expert Insights
"The SLM3500 is my go-to LDO for noise-sensitive applications. I've used this part in RF transceiver power supplies where the 75dB PSRR effectively rejects switching noise from upstream DC-DC converters. One 5G small cell project used the SLM3500 to power the RF front-end, achieving excellent EVM performance. The 15μVrms noise figure is excellent for this class of device - comparable to premium brands at a fraction of the cost. The dropout voltage of 250mV at 500mA allows efficient operation from a 3.3V rail down to 3.0V output. For best noise performance, I recommend using a 10μF ceramic output capacitor with X7R dielectric. The adjustable version provides flexibility for various voltage rails. Overall, an excellent choice for post-regulation after switching converters."
Ultra-low noise LDO with excellent PSRR for RF applications
— 刘建国, BeiLuo
Frequently Asked Questions
What makes SLM3500 suitable for RF applications?
The SLM3500 is ideal for RF applications due to: (1) Ultra-low output noise of 15μVrms - minimizes phase noise in RF oscillators and mixers. (2) High PSRR of 75dB at 1kHz - effectively rejects ripple from upstream switching converters at frequencies where RF circuits are most sensitive. (3) Fast transient response - maintains stable output during rapid load changes common in burst-mode RF transmission. (4) Clean startup - soft-start prevents voltage overshoot that could damage sensitive RF components. (5) Wide bandwidth PSRR - maintains >50dB PSRR up to 100kHz, covering common switching frequencies. For RF applications, place the LDO close to the RF circuit and use adequate output capacitance for best performance.
Use SLM3500 for RF circuits requiring clean power; place close to load for best results.
How do I minimize output noise from SLM3500?
To achieve lowest output noise from SLM3500: (1) Output capacitor - use 10μF ceramic capacitor (X7R) for lowest noise. Larger capacitors reduce noise further. (2) Bypass capacitor - add 100nF ceramic close to the load for high-frequency noise filtering. (3) Input supply - provide clean input voltage; use upstream filtering if necessary. The PSRR helps but clean input is still important. (4) PCB layout - place LDO close to the load, minimize trace length between LDO output and load. Use ground plane for return path. (5) Load current - noise is typically specified at nominal load; very light or very heavy loads may have different characteristics. (6) Temperature - noise performance is specified at 25°C; expect slight variation over temperature range.
Use 10μF output capacitor, place close to load, keep traces short for lowest noise.